CN113227210A - Optical film and flexible display device - Google Patents

Optical film and flexible display device Download PDF

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Publication number
CN113227210A
CN113227210A CN201980085975.XA CN201980085975A CN113227210A CN 113227210 A CN113227210 A CN 113227210A CN 201980085975 A CN201980085975 A CN 201980085975A CN 113227210 A CN113227210 A CN 113227210A
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formula
structural unit
group
represented
optical film
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杉山纮子
宫本皓史
池内淳一
增井建太朗
金成民
片宝蓝
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Sumitomo Chemical Co Ltd
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Sumitomo Chemical Co Ltd
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Priority claimed from JP2019213442A external-priority patent/JP2021084941A/en
Priority claimed from JP2019218189A external-priority patent/JP7365211B2/en
Priority claimed from JP2019218184A external-priority patent/JP2020125454A/en
Priority claimed from JP2019218259A external-priority patent/JP2020109154A/en
Application filed by Sumitomo Chemical Co Ltd filed Critical Sumitomo Chemical Co Ltd
Priority claimed from PCT/JP2019/050541 external-priority patent/WO2020138045A1/en
Publication of CN113227210A publication Critical patent/CN113227210A/en
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G73/00—Macromolecular compounds obtained by reactions forming a linkage containing nitrogen with or without oxygen or carbon in the main chain of the macromolecule, not provided for in groups C08G12/00 - C08G71/00
    • C08G73/06—Polycondensates having nitrogen-containing heterocyclic rings in the main chain of the macromolecule
    • C08G73/10—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
    • C08G73/14—Polyamide-imides
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
    • G09F9/30—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements
    • G09F9/301—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements flexible foldable or roll-able electronic displays, e.g. thin LCD, OLED
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2379/00—Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen, or carbon only, not provided for in groups C08J2361/00 - C08J2377/00
    • C08J2379/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
    • C08J2379/08—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Optics & Photonics (AREA)
  • Human Computer Interaction (AREA)
  • Materials Engineering (AREA)
  • Macromolecular Compounds Obtained By Forming Nitrogen-Containing Linkages In General (AREA)
  • Manufacture Of Macromolecular Shaped Articles (AREA)

Abstract

The invention provides an optical film with excellent appearance quality, which does not damage the appearance quality of the optical film even contacting with alcohol. An optical film comprising a polyamideimide-based resin having at least a structural unit represented by formula (a) derived from a tetracarboxylic acid compound, a structural unit represented by formula (b) derived from a dicarboxylic acid compound, and a structural unit represented by formula (c) derived from a diamine compound, the polyamideimide-based resin comprising at least one structural unit selected from the group consisting of a structural unit (a1) wherein Y in formula (a) is represented by formula (1) as the structural unit derived from the tetracarboxylic acid compound, and a structural unit (b1) wherein Z in formula (b) is represented by formula (1) as the structural unit derived from the dicarboxylic acid compound, the optical film being based on L in reflected light measurement*a*b*Lightness L of the chromaticity System1 *L-base of the optical film after 40 minutes of contact with ethanol in measurement of color difference of surface*a*b*Lightness L of the chromaticity System2 *Absolute value of difference Δ L*Is 0.5 or less. In the formula (a), Y represents a 4-valent organic group, in the formula (b), Z represents a 2-valent organic group, in the formula (c), X represents a 2-valent organic group, RcIndependently of each other, represents a hydrogen atom or a chemical bond. In the formula (1), RaIndependently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, RaWherein the hydrogen atoms contained in (A) are independently substituted by halogen atoms, n represents an integer of 0 to 2, R represents a bond*Represents a chemical bond in the case where Y is represented by formula (1), and represents R in the case where Z is represented by formula (1)a。

Description

Optical film and flexible display device
Technical Field
The present invention relates to an optical film containing a polyamideimide resin and a flexible display device including the optical film.
Background
At present, display devices such as liquid crystal display devices and organic EL display devices are widely used not only for televisions but also for various applications such as mobile phones and smartwatches. Conventionally, glass has been used as a front panel of such a display device. However, glass has high transparency and can exhibit high hardness depending on the type, but on the other hand, it is very rigid and easily broken, and therefore, it is difficult to use it as a front panel material for a flexible display device.
Therefore, studies have been made on flexible use of polymer materials as materials replacing glass. A front panel made of a polymer material is expected to be used for various applications because it is easy to exhibit flexibility. As one of polymer materials having flexibility, for example, an optical film using a polyamideimide resin has been studied (patent documents 1 and 2).
Documents of the prior art
Patent document
Patent document 1: japanese laid-open patent publication No. 2015-521686
Patent document 2: japanese patent laid-open publication No. 2018-119132
Disclosure of Invention
Problems to be solved by the invention
When applied to a display device, an optical film used as a front panel material of a flexible display device is required to have high appearance quality, that is, uniform color without unevenness when viewed from all viewing angles over the entire surface thereof. On the other hand, foreign matter and defects are particularly required to be small. In order to reduce foreign matter and defects, the production equipment is cleaned with alcohol such as ethanol in the production process. However, after the production equipment such as the guide roll is cleaned with alcohol, the alcohol remaining in the production equipment comes into contact with the optical film, and the appearance quality of the optical film may be degraded. In addition, in a flexible display device incorporating the optical film, a situation in which a user wipes a surface with a cleaning agent containing an alcohol component in order to clean the surface is also conceivable, and the appearance quality of the optical film may be degraded depending on the state of contact with the cleaning agent containing the alcohol component.
Accordingly, an object of the present invention is to provide an optical film which does not deteriorate the appearance quality of the optical film even when the optical film is brought into contact with an alcohol.
Means for solving the problems
The inventors of the present application have intensively studied to solve the above-mentioned problems, and as a result, have found that the L-base content in the reflection measurement before and after the contact with an alcohol, which contains a polyamideimide resin having at least a specific structural unit*a*b*The present inventors have completed the present invention by finding that an optical film having a brightness variation of a chromaticity system within a predetermined range has high appearance quality even after contact with an alcohol.
That is, the present invention includes the following preferred embodiments.
An optical film comprising a polyamideimide resin having at least a structural unit represented by formula (a) derived from a tetracarboxylic acid compound, a structural unit represented by formula (b) derived from a dicarboxylic acid compound, and a structural unit represented by formula (c) derived from a diamine compound, wherein the polyamideimide resin comprises at least one structural unit selected from the group consisting of a structural unit (a1) wherein Y in formula (a) is represented by formula (1) as the structural unit derived from a tetracarboxylic acid compound, and a structural unit (b1) wherein Z in formula (b) is represented by formula (1) as the structural unit derived from a dicarboxylic acid compound,
the optical film is based on L in reflected light measurement*a*b*Lightness L of the chromaticity System1 *L-base of the optical film after 40 minutes of contact with ethanol in measurement of color difference of surface*a*b*Lightness L of the chromaticity System2 *Absolute value of difference Δ L*Is 0.5 or less.
[ chemical formula 1]
Figure BDA0003131483550000031
[ in the formula (a), Y represents a 4-valent organic group, in the formula (b), Z represents a 2-valent organic group, in the formula (c), X represents a 2-valent organic group, RcIndependently of one another, represents a hydrogen atom or a chemical bond]
[ chemical formula 2]
Figure BDA0003131483550000032
[ in the formula (1), RaIndependently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, RaThe hydrogen atoms contained in (a) may be substituted independently of each other by halogen atoms,
n represents an integer of 0 to 2,
denotes a chemical bond, R*Represents a chemical bond in the case where Y is represented by formula (1), and represents R in the case where Z is represented by formula (1)a]
[ 2] the optical film according to [ 1], wherein L is the basis for the reflected light measurement*a*b*B of the optical film of the color system1 *B of the optical film after 40 minutes of contact with ethanol2 *Absolute value of the difference Δ b*Is 0.1 or less.
[ 3] the optical film according to [ 1] or [ 2], wherein the thickness of the optical film is 25 μm or more and 100 μm or less.
The optical film according to any one of [ 1] to [ 3], wherein the optical film has a haze of 5% or less.
The optical film according to any one of [ 1] to [ 4] above, wherein the polyamideimide resin contains the structural unit (b2) represented by the formula (2) as a structural unit derived from a dicarboxylic acid compound, and contains the structural unit (c1) represented by the formula (3) as a structural unit derived from a diamine compound.
[ chemical formula 3]
Figure BDA0003131483550000041
[ in the formula (2), Z1Represents a 2-valent aromatic group which may have a substituent, the 2-valent aromatic group being a monocyclic aromatic ring or a condensed polycyclic aromatic ring, and represents a bond]
[ chemical formula 4]
Figure BDA0003131483550000042
[ in the formula (3), X1Represents an optionally substituted 2-valent aromatic group, RcIndependently of one another, represents a hydrogen atom or a chemical bond]
[ 6] the optical film according to [ 5], wherein X in the formula (3)1Represented by formula (4).
[ chemical formula 5]
Figure BDA0003131483550000043
[ in the formula (4), RbIndependently represent an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, RbWherein the hydrogen atoms contained in (A) are independently substituted by halogen atoms, r is independently an integer of 1 to 4]
The optical film according to any one of [ 1] to [ 6] above, wherein the polyamideimide resin further comprises at least one structural unit selected from the group consisting of a structural unit (b3) wherein Z in formula (b) is represented by formula (5) as a structural unit derived from a dicarboxylic acid compound, a structural unit (c2) wherein X in formula (c) is represented by formula (5) as a structural unit derived from a diamine compound, and a structural unit (a2) wherein Y in formula (a) is represented by formula (6) as a structural unit derived from a tetracarboxylic acid compound.
[ chemical formula 6]
Figure BDA0003131483550000044
[ formula (5) wherein Ar is1Independently of each other, a 2-valent aromatic group which may have a substituent,
v represents a single bond, -O-, diphenylmethylene, a linear, branched or alicyclic 2-valent hydrocarbon group having 1 to 12 carbon atoms, or-SO2-, -S-, -CO-or-N (R)12) -, wherein the hydrogen atoms contained in the hydrocarbon group independently of each other may be substituted by halogen atoms, R12Represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom,
m represents an integer of 1 to 3, wherein when m is 2 or 3, a plurality of V may be the same or different,
represents a chemical bond ]
[ chemical formula 7]
Figure BDA0003131483550000051
In [ formula (6), Ar2Independently of each other, a 3-valent aromatic group which may have a substituent,
s represents an integer of 0 to 2,
Ar1v and Ar for formula (5)1V and x are as defined, wherein when s is 2, there are a plurality of V and Ar1Each can beThese are the same or different, and V in the formula (6) is not a single bond]
The optical film according to the above [ 7], wherein the formulae (5) and (6) are represented by the formula (7).
[ chemical formula 8]
Figure BDA0003131483550000052
[ in the formula (7), R1Independently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, R1The hydrogen atoms contained in (a) may be substituted independently of each other by halogen atoms,
R*represents R1Or a chemical bond to the substrate,
the symbol represents a chemical bond,
v represents a single bond, -O-, diphenylmethylene, a linear, branched or alicyclic 2-valent hydrocarbon group having 1 to 12 carbon atoms, or-SO2-, -S-, -CO-or-N (R)12) -, wherein the hydrogen atoms contained in the hydrocarbon group independently of each other may be substituted by halogen atoms, R12Represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom, wherein V is not a single bond when formula (6) is represented by formula (7)
The optical film according to [ 8] above, wherein the formula (7) is represented by formula (7 ') or formula (7').
[ chemical formula 9]
Figure BDA0003131483550000061
[ formula (7') wherein R*Represents a hydrogen atom or a chemical bond]
[ chemical formula 10]
Figure BDA0003131483550000062
[ in the formula (7'), represents a chemical bond ]
[ 10] the optical film according to any one of [ 1] to [ 9] above, wherein the formula (1) is represented by formula (1').
[ chemical formula 11]
Figure BDA0003131483550000063
[ formula (1'), "represents a bond, R*A chemical bond in the case where Y is represented by formula (1), and a hydrogen atom in the case where Z is represented by formula (1)]
The optical film according to any one of [ 1] to [ 10] above, which is a film for a front panel of a flexible display device.
A flexible display device comprising the optical film according to any one of [ 1] to [ 11 ].
The flexible display device according to [ 13] above [ 12], further comprising a touch sensor.
The flexible display device according to any one of the above [ 12] and [ 13], further comprising a polarizing plate.
ADVANTAGEOUS EFFECTS OF INVENTION
The optical film of the present invention has high appearance quality which is not damaged by contact with alcohol.
Detailed Description
Hereinafter, embodiments of the present invention will be described in detail. The scope of the present invention is not limited to the embodiments described herein, and various modifications can be made without departing from the spirit of the present invention.
[ optical film ]
The optical film of the present invention is an optical film comprising a polyamideimide resin having at least a structural unit represented by formula (a) derived from a tetracarboxylic acid compound, a structural unit represented by formula (b) derived from a dicarboxylic acid compound, and a structural unit represented by formula (c) derived from a diamine compound, wherein the polyamideimide resin comprises a resin selected from the group consisting of the structural units derived from a tetracarboxylic acid compound, wherein Y in formula (a) is represented by formula (1): at least one structural unit selected from the group consisting of the structural unit (a1) represented by the formula (a) and the structural unit (b1) represented by the formula (1) wherein Z in the formula (b) is a structural unit derived from a dicarboxylic acid compound,
the optical film is based on L in reflected light measurement*a*b*Lightness L of the chromaticity System1 *L-base of the optical film after 40 minutes of contact with ethanol in measurement of color difference of surface*a*b*Lightness L of the chromaticity System2 *Absolute value of difference Δ L*Is 0.5 or less. In the present specification, a structural unit represented by formula (1) for Y in formula (a) is also referred to as "structural unit (a 1)", and a structural unit represented by formula (1) for Z in formula (b) is also referred to as "structural unit (b 1)".
[ chemical formula 12]
Figure BDA0003131483550000081
[ in the formula (a), Y represents a 4-valent organic group, in the formula (b), Z represents a 2-valent organic group, in the formula (c), X represents a 2-valent organic group, RcIndependently of one another, represents a hydrogen atom or a chemical bond]
[ chemical formula 13]
Figure BDA0003131483550000082
[ in the formula (1), RaIndependently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, RaThe hydrogen atoms contained in (a) may be substituted independently of each other by halogen atoms,
n represents an integer of 0 to 2,
denotes a chemical bond, R*Represents a chemical bond in the case where Y is represented by formula (1), and represents R in the case where Z is represented by formula (1)a]
For the inventionOptical film, L-base of optical film in reflected light measurement*a*b*Lightness L of the chromaticity System1 *L-base of the optical film after 40 minutes of contact with ethanol in measurement of color difference of surface*a*b*Lightness L of the chromaticity System2 *Absolute value of difference Δ L*Is 0.5 or less. Δ L*If the amount exceeds 0.5, the optical film may be deteriorated in appearance quality by contact with ethanol. From the viewpoint of more easily improving the appearance quality,. DELTA.L*Preferably 0.3 or less, more preferably 0.2 or less, further preferably 0.1 or less, and usually 0 or more. Note that Δ L*Is the lightness L in reflected light measurement of the optical film of the present invention1 *Lightness L of the optical film after 40 minutes of contact of the optical film of the present invention with ethanol2 *The absolute value of the difference. As a method for contacting the optical film with ethanol for 40 minutes, the following method was employed: ethanol was dropped on the optical film, and a cover glass was attached to maintain the optical film in contact with the ethanol for 40 minutes. Specific examples thereof include the methods described in examples. In addition, the L-base in the reflected light measurement*a*b*Lightness L of the chromaticity System*The value can be measured using a spectrocolorimeter under the conditions described in examples, for example. As making Δ L*The method within the above range includes: a method for producing an optical film using a polyamideimide resin described later, a method for adjusting a solvent in the film by adjusting a film-forming solvent, a drying condition of the film, and a temperature, a method for providing a protective layer, and the like. The amount of solvent in the film was adjusted by adjusting the film-forming solvent, the drying conditions of the film, and the temperature so as to adjust Δ L*When the amount of the solvent is adjusted within the above range, the amount of the solvent in the film may be adjusted to 0.1% to 1.0%, for example, to adjust Δ L to the range of 0.1% to 1.0%, although the amount depends on the type of the solvent*Adjusted to within the desired range. In addition, Δ L is formed by a method of providing a protective layer*When the content is adjusted to be within the above range, Δ L may be adjusted by providing a protective layer such as a hard coat layer to which chemical resistance is imparted on the optical film*Adjusted to the above range.
In the optical film of the present invention, the structure represented by formula (1) is contained in the polyamideimide resin by including at least one structural unit selected from the group consisting of a structural unit (a1) in which Y in formula (a) is represented by formula (1) and a structural unit (b1) in which Z in formula (b) is represented by formula (1). The structure represented by formula (1) is a structure having high rigidity, and a portion having rigidity is included in the skeleton of the polyamideimide resin. As a result, surprisingly, it is considered that the alcohol resistance of the obtained optical film is improved, and the appearance quality of the optical film is easily prevented from being lowered by the contact with alcohol. Further, the polyamide-imide resin contains the above-mentioned polyamide-imide resin and has a Δ L*In the case of within the above range, high appearance quality of the optical film can be achieved. Here, for example, when the optical film is used as a front panel of a display device, a surrounding background is reflected on the optical film. Particularly in the case of using an optical film in a flexible display device, the background reflected in the optical film is viewed from various angles. If the background of the reflection looks locally unclear, for example, the user feels discomfort and the feeling of quality of the product is considered to be reduced. Such an appearance quality is a quality that can be evaluated by, for example, the method described in the examples, and specifically, a quality that a reflected background can be clearly seen without a local blur. The appearance quality can be easily and clearly judged particularly when the background is black.
Containing the polyamideimide resin described later and having a.DELTA.L*The reason why the optical film of the present invention having a thickness of 0.5 or less is improved in appearance quality is not clear, but in the present invention,. DELTA.L*The change in the reflected light on the surface of the optical film due to contact with ethanol was shown. Therefore, it is considered that even if the change caused by contact with ethanol is slight or hardly visible by visual observation, Δ L is a value*If the amount exceeds 0.5, the reflected light varies slightly, and therefore, when the optical film is incorporated into a flexible display or the like, the optical film looks white depending on the angleThe colored portion may deteriorate the appearance quality of the optical film.
L-base of the optical film of the present invention in reflected light measurement*a*b*Lightness L of the chromaticity System*The value is preferably 5 or less, more preferably 3 or less, further preferably 2.5 or less, preferably 0 or more, more preferably 0.1 or more, further preferably 0.2 or more. If L is*When the value is within the above range, the visibility is good when the optical film is used.
For the optical film of the present invention, L-base in reflectance measurement*a*b*B of the optical film of the color system1 *B of the optical film after 40 minutes of contact with ethanol2 *Absolute value of the difference Δ b*Preferably 0.1 or less, more preferably 0.08 or less, further preferably 0.05 or less, and usually 0 or more. Note that Δ b*Is b1 *And b2 *The absolute value of the difference. The method of contacting the optical film with ethanol for 40 minutes is not particularly limited, and examples thereof include the methods described in examples. In addition, the L-base in the reflected light measurement*a*b*B of the color system*The value can be measured under the conditions described in examples, for example, by using spectrocolorimetry. As a result of Δ b*The method within the above range includes a method of producing an optical film using a polyamideimide resin described later, a method of adjusting a film forming solvent, drying conditions of the film, and a temperature to adjust the amount of the solvent in the film, a method of providing a protective layer, and the like. Consider Δ b*In the case of the above range, the color tone of the reflected light is easily made uniform, and thus the appearance quality is more easily improved.
L-base of the optical film of the present invention in reflected light measurement*a*b*B of the color system*The value is preferably 2 or less, more preferably 1 or less, further preferably 0.5 or less, preferably-2 or more, more preferably-1 or more, further preferably-0.5 or more. If b is*If the value is within the above range, the reflected light does not have a yellow hueThe blue color tone tends to improve the appearance when used as an optical film.
L-base of the optical film of the present invention in reflected light measurement*a*b*A of the color system*The value is preferably 2 or less, more preferably 1 or less, further preferably 0.5 or less, preferably-2 or more, more preferably-1 or more, further preferably-0.5 or more. If a*When the value is within the above range, the reflected light does not have a red hue or a green hue, and the appearance tends to be good when the film is used as an optical film.
In one embodiment of the present invention, the content of the polyamideimide resin in the optical film is preferably 10 parts by mass or more, more preferably 30 parts by mass or more, further preferably 50 parts by mass or more, preferably 99.5 parts by mass or less, more preferably 95 parts by mass or less, per 100 parts by mass of the optical film. When the content of the polyamideimide resin is within the above range, the appearance quality, optical characteristics, elastic modulus and total light transmittance of the optical film are easily improved.
The thickness of the optical film of the present invention is preferably 25 μm or more, more preferably 30 μm or more, further preferably 35 μm or more, preferably 100 μm or less, more preferably 80 μm or less, further preferably 60 μm or less, and may be a combination of these upper and lower limits. When the thickness of the optical film is within the above range, the appearance quality and optical characteristics of the optical film are more easily improved. The thickness of the optical film can be measured using a micrometer, and can be measured, for example, by the method described in examples.
The optical film of the present invention has a yellowness index (hereinafter, may be referred to as YI value) of preferably 7 or less, more preferably 4 or less, usually-5 or more, preferably-2 or more. When the YI value of the optical film is not more than the above upper limit, the transparency becomes good, and when the optical film is applied to a front panel of a display device, high visibility can be contributed. The YI value can be calculated based on the formula of YI × (1.2769X-1.0592Z)/Y by measuring the transmittance to light of 300 to 800nm using an ultraviolet-visible near-infrared spectrophotometer to obtain the tristimulus value (X, Y, Z).
From the viewpoint of easily preventing wrinkles, scratches, and the like of the optical film, the elastic modulus of the optical film of the present invention is preferably 5.2GPa or more, more preferably 5.5GPa or more, further preferably 5.8GPa or more, further more preferably 6.0GPa or more, particularly preferably 6.2GPa or more, particularly preferably 6.4GPa or more, and usually 100GPa or less. The elastic modulus can be measured using a tensile tester (the distance between chucks is 50mm, and the tensile speed is 10 mm/min), and can be measured, for example, by the method described in examples.
The optical film of the present invention has a total light transmittance of preferably 80% or more, more preferably 85% or more, further preferably 88% or more, further more preferably 89% or more, particularly preferably 90% or more, and usually 100% or less. When the total light transmittance is not less than the above lower limit, visibility is easily improved when the optical film, particularly the front panel, is incorporated in a display device. The optical film of the present invention generally exhibits a high total light transmittance, and therefore, for example, the light emission intensity of a display element or the like required to obtain a certain luminance can be suppressed as compared with the case of using a film having a low transmittance. Therefore, power consumption can be reduced. For example, when the optical film of the present invention is incorporated in a display device, bright display tends to be obtained even when the amount of light from a backlight is reduced, and this contributes to energy saving. The total light transmittance may be, for example, a value in accordance with JIS K7361-1: 1997. the haze was determined using a haze computer. The total light transmittance may be a total light transmittance within a range of a thickness of an optical film to be described later. In the present specification, the term "excellent optical properties of the optical film" means high total light transmittance and/or low haze.
The haze of the optical film of the present invention is preferably 5% or less, more preferably 4% or less, further preferably 3% or less, further more preferably 2.5% or less, particularly preferably 2% or less, particularly preferably 1% or less, particularly preferably 0.8% or less, particularly preferably 0.5% or less, and usually 0.01% or more. When the haze of the optical film is not more than the above upper limit, the visibility is easily improved when the optical film is incorporated into a display device, particularly as a front panel. The haze may be measured according to JIS K7136: 2000. the haze was determined using a haze computer.
The pencil hardness of at least one surface of the optical film of the present invention is preferably HB or more, and more preferably F or more. When the pencil hardness of at least one surface of the optical film is equal to or higher than the above hardness, damage or the like on the surface of the optical film can be easily prevented. The pencil hardness may be measured in accordance with JIS K5600-5-4: 1999, the measurement was carried out.
[ Polyamide imide resin ]
The optical film of the present invention comprises a polyamideimide resin having at least a structural unit represented by formula (a) derived from a tetracarboxylic acid compound, a structural unit represented by formula (b) derived from a dicarboxylic acid compound, and a structural unit represented by formula (c) derived from a diamine compound, wherein the polyamideimide resin comprises at least one structural unit selected from the group consisting of a structural unit (a1) wherein Y in formula (a) is represented by formula (1) as the structural unit derived from the tetracarboxylic acid compound, and a structural unit (b1) wherein Z in formula (b) is represented by formula (1) as the structural unit derived from the dicarboxylic acid compound. In the present specification, the structural unit represented by the formula (a) derived from a tetracarboxylic acid compound is also referred to as a "structural unit (a)", the structural unit represented by the formula (b) derived from a dicarboxylic acid compound is also referred to as a "structural unit (b)", and the structural unit represented by the formula (c) derived from a diamine compound is also referred to as a "structural unit (c)".
[ chemical formula 14]
Figure BDA0003131483550000131
[ in the formula (a), Y represents a 4-valent organic group, in the formula (b), Z represents a 2-valent organic group, in the formula (c), X represents a 2-valent organic group, RcIndependently of one another, represents a hydrogen atom or a chemical bond]
[ chemical formula 15]
Figure BDA0003131483550000132
[ in the formula (1), RaIndependently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, RaThe hydrogen atoms contained in (a) may be substituted independently of each other by halogen atoms,
n represents an integer of 0 to 2,
denotes a chemical bond, R*Represents a chemical bond in the case where Y is represented by formula (1), and represents R in the case where Z is represented by formula (1)a]
The polyamideimide resin generally has a plurality of structural units (a), a plurality of structural units (b), a plurality of structural units (c), and optionally a plurality of other structural units. In the present specification, the term "polyamideimide resin contained in the optical film of the present invention contains a structural unit (a1) represented by formula (1) wherein Y in formula (a) is a structural unit (a) derived from a tetracarboxylic acid compound means that at least a part of the structural units (a) in the plurality of structural units (a) contained in the polyamideimide resin is a structural unit (a1) represented by formula (1) wherein Y in formula (a) is represented. The polyamideimide resin contained in the optical film of the present invention, which contains the structural unit (b1) wherein Z in formula (b) is represented by formula (1) as the structural unit (b) derived from a dicarboxylic acid compound, means that at least a part of the structural units (b) in the plurality of structural units (b) contained in the polyamideimide resin are the structural units (b1) wherein Z in formula (b) is represented by formula (1). The above description is also applicable to other descriptions in the present specification. The chemical bond in the formulae (a) to (c) is a chemical bond that bonds to an adjacent structural unit.
In the present invention, the polyamideimide resin includes at least a structural unit (a), a structural unit (b) and a structural unit (c), and here, the structural unit (a) derived from a tetracarboxylic acid compound and the structural unit (c) derived from a diamine compound are usually included in the polyamideimide resin so as to form an imide bond represented by the formula (D), and the structural unit (b) derived from a dicarboxylic acid compound and the structural unit (c) derived from a diamine compound are included in the polyamideimide resin so as to form an amide bond represented by the formula (E).
[ chemical formula 16]
Figure BDA0003131483550000141
[ in the formula (D), Y represents a 4-valent organic group, X represents a 2-valent organic group, and X represents a chemical bond ]
[ chemical formula 17]
Figure BDA0003131483550000142
[ in the formula (E), Z and X independently represent a 2-valent organic group and represent a bond ]
In the formula (D), Y and a moiety having 4 carbonyl groups correspond to the structural unit (a) derived from a tetracarboxylic acid compound, Z and a moiety having 2 carbonyl groups correspond to the structural unit (b) derived from a dicarboxylic acid compound, and X and a moiety having an amino group correspond to the structural unit (c) derived from a diamine compound. In the portions corresponding to the structural unit (c) derived from the diamine compound in the formulae (D) and (E), one side of the bond of X representing the 2-valent organic group is bonded to the amino group, and the other side of the bond of X represents the adjacent structural unit. When the structural units represented by the formulae (D) and (E) are repeated, the chemical bond represented by x bonded to the adjacent structural unit is bonded to the amino moiety in the formula (D) or (E). Therefore, X and the moiety having an amino group in the formula (D) and the formula (E) can be said to be a moiety corresponding to the structural unit (c) derived from the diamine compound.
In the present invention, the polyamideimide resin contains at least one structural unit selected from the group consisting of a structural unit (a1) derived from a tetracarboxylic acid compound, wherein Y in formula (a) is represented by formula (1), and a structural unit (b1) derived from a dicarboxylic acid compound, wherein Z in formula (b) is represented by formula (1). In this case, the polyamideimide resin contained in the optical film of the present invention has at least one structural unit selected from the group consisting of a structural unit (D) in which Y is represented by formula (1) and a structural unit (E) in which Z is represented by formula (1). In the formulae (D) and (E), each symbol denotes a chemical bond to an adjacent structural unit.
In the present invention, the polyamideimide resin has a structural unit (a) derived from a tetracarboxylic acid compound, a structural unit (b) derived from a dicarboxylic acid compound, and a structural unit (c) derived from a diamine compound, and may further have a structural unit derived from a monomer other than the above-mentioned monomers, as long as the polyamideimide resin contains at least one structural unit selected from the group consisting of a structural unit (a1) which is at least a part of the structural unit (a) and a structural unit (b1) which is at least a part of the structural unit (b). Specifically, the polyamideimide resin of the present invention comprises at least 1 or 2 or more kinds of structural units (a) derived from a tetracarboxylic acid compound, 1 or 2 or more kinds of structural units (b) derived from a dicarboxylic acid compound, and 1 or 2 or more kinds of structural units (c) derived from a diamine compound, wherein at least a part of the structural units (a) comprises the structural unit (a1), or at least a part of the structural units (b) comprises the structural unit (b1), or at least a part of the structural units (a) comprises the structural unit (a1), and at least a part of the structural units (b) comprises the structural unit (b 1).
The polyamideimide resin contains at least one structural unit selected from the group consisting of a structural unit (a1) wherein Y in formula (a) is represented by formula (1) as a structural unit derived from a tetracarboxylic acid compound, and a structural unit (b1) wherein Z in formula (b) is represented by formula (1) as a structural unit derived from a dicarboxylic acid compound.
[ chemical formula 18]
Figure BDA0003131483550000161
[ in the formula (1),Raindependently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, RaThe hydrogen atoms contained in (a) may be substituted independently of each other by halogen atoms,
n represents an integer of 0 to 2,
denotes a chemical bond, R*Represents a chemical bond in the case where Y is represented by formula (1), and represents R in the case where Z is represented by formula (1)a]
The polyamideimide resin contained in the optical film of the present invention may have 1 kind of structural unit (a1) in which Y in formula (a) is represented by formula (1), 2 or more kinds of structural units (a1) in which Y in formula (a) is represented by formula (1), 1 kind of structural unit (b1) in which Z in formula (b) is represented by formula (1), 2 or more kinds of structural units (b1) in which Y in formula (b) is represented by formula (1), or both of them. From the viewpoint of more easily improving the appearance quality of the optical film, the polyamideimide resin according to the present invention preferably contains at least 1 kind of the structural unit (a1) represented by formula (1) wherein Y in formula (a) is a structural unit derived from a tetracarboxylic acid compound.
R in the formula (1)aIndependently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, RaThe hydrogen atoms contained in (a) may be substituted by halogen atoms independently of each other. In a preferred embodiment of the present invention, R is a group represented by formula (1) in which the rigidity of the structure can be easily improved, the rigidity can be easily imparted to the skeleton of the polyamideimide resin, and the appearance quality, total light transmittance and elastic modulus of the optical film of the present invention can be easily improvedaIndependently of each other, the alkyl group having 1 to 12 carbon atoms, the alkoxy group having 1 to 12 carbon atoms, or the aryl group having 6 to 12 carbon atoms preferably represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, a hydrogen atom or a halogen atom, and a1 to 3 carbon atomsAlkyl, especially preferably represents a hydrogen atom.
Examples of the alkyl group having 1 to 12 carbon atoms include a linear, branched or alicyclic alkyl group having 1 to 12 carbon atoms. Examples of the linear, branched or alicyclic alkyl group having 1 to 12 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, 2-methyl-butyl, 3-methylbutyl, 2-ethyl-propyl, n-hexyl, n-heptyl, n-octyl, tert-octyl, n-nonyl, n-decyl, cyclopentyl, cyclohexyl and the like. The alkyl group having 1 to 12 carbon atoms may be a linear alkyl group, a branched alkyl group, or an alicyclic alkyl group having an alicyclic hydrocarbon structure. The number of carbon atoms of the alkyl group having 1 to 12 carbon atoms is preferably 1 to 6, more preferably 1 to 4, and further preferably 1 to 3. The alkyl group having 1 to 12 carbon atoms may be a group in which at least 1 hydrogen atom is independently substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, or a carboxyl group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Here, when the alkyl group having 1 to 12 carbon atoms is substituted with a substituent containing a carbon atom (for example, an alkyl group having 1 to 4 carbon atoms), the number of carbon atoms contained in the substituent is not included in the number of carbon atoms of the alkyl group having 1 to 12 carbon atoms. For example, the group in which the alkyl group having 1 to 12 carbon atoms is substituted with an alkyl group having 1 to 4 carbon atoms is a group in which the alkyl group having 1 to 12 carbon atoms is the main chain and at least 1 hydrogen atom of the alkyl group is substituted with an alkyl group having 1 to 4 carbon atoms. When the number of carbon atoms of the alkyl moiety which becomes the main chain is 1 to 12, the number of carbon atoms of the alkyl group as a whole may be more than 12. In the case where the number of carbon atoms of the alkyl group exceeds 12, the group in which an alkyl group having 1 to 12 carbon atoms is substituted with an alkyl group having 1 to 4 carbon atoms is also included in the definition of a branched alkyl group having 1 to 12 carbon atoms.
Examples of the alkoxy group having 1 to 12 carbon atoms include methoxy, ethoxy, propyloxy, isopropyloxy, n-butoxy, isobutyloxy, tert-butoxy, pentyloxy, hexyloxy, cyclohexyloxy, heptyloxy, octyloxy, nonyloxy, decyloxy and the like. The alkyl moiety and/or the alkylene moiety in the C1-12 alkoxy group may be any of linear, branched, or alicyclic. The alkoxy group having 1 to 12 carbon atoms preferably has 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms, and still more preferably 1 to 3 carbon atoms. The alkoxy group having 1 to 12 carbon atoms may be a group in which at least 1 hydrogen atom is independently substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, or a carboxyl group. Examples of the halogen atom include the atoms described above. When the alkoxy group having 1 to 12 carbon atoms is substituted with a substituent containing a carbon atom, the number of carbon atoms contained in the substituent is not included in the number of carbon atoms of the alkoxy group having 1 to 12 carbon atoms.
Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and a biphenyl group. The number of carbon atoms of the aryl group having 6 to 12 carbon atoms is preferably 6, 10 or 12. The above-mentioned aryl group having 6 to 12 carbon atoms may be a group in which at least 1 hydrogen atom is independently substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, or a carboxyl group. Examples of the halogen atom include the atoms described above. When the aryl group having 6 to 12 carbon atoms is substituted with a substituent containing a carbon atom, the number of carbon atoms contained in the substituent is not included in the number of carbon atoms of the aryl group having 6 to 12 carbon atoms.
RaThe hydrogen atoms contained in (a) may be substituted by halogen atoms independently of each other. Examples of the halogen atom include the atoms described above.
N in formula (1) represents an integer of 0 to 2, and n is preferably 0 or 1, and more preferably 0, from the viewpoint of easily improving the total light transmittance and elastic modulus of an optical film obtained using a polyamideimide resin.
When Y in the formula (a) is represented by the formula (1), R and x in the formula (1)*Is shown anda chemical bond in which a moiety derived from a carboxyl group (for example, an imide group moiety) is bonded in a structural unit derived from a tetracarboxylic acid compound. In the present specification, the tetracarboxylic acid compound may be a compound selected from the group consisting of a compound having 4 carboxyl groups, a carboxylic acid halide or a carboxylic acid ester of the compound, and a carboxylic acid dianhydride obtained by dehydration condensation of 2 carboxyl groups adjacent to each other, and the tetracarboxylic acid compound is preferably a tetracarboxylic acid dianhydride from the viewpoint of ease of polymerization in synthesis.
The tetracarboxylic acid compound that provides the structural unit (a1) in which Y in formula (a) is represented by formula (1) is represented by formula (8) in the case where the tetracarboxylic acid compound is a tetracarboxylic dianhydride, for example.
[ chemical formula 19]
Figure BDA0003131483550000191
[ in the formula (8), RaAnd n is as defined for formula (1)]
When Z in formula (b) is represented by formula (1), formula (1) represents a chemical bond to the carbonyl carbon in the structural unit derived from the dicarboxylic acid compound. In the present specification, the dicarboxylic acid compound may be a compound having 2 carboxyl groups, a carboxylic acid halide and/or a carboxylic acid ester of the compound.
The dicarboxylic acid compound which provides the structural unit (b1) wherein Z in formula (b) is represented by formula (1) is represented by formula (12) in the case where the dicarboxylic acid compound is dicarboxylic acid dichloride, for example.
[ chemical formula 20]
Figure BDA0003131483550000192
[ formula (12) wherein RaAnd n is as defined for formula (1)]
In the polyamideimide resin contained in the optical film of the present invention, the structural unit represented by formula (1) represents Y in formula (a) based on all the structural units contained in the polyamideimide resin(a1) And the total amount of the structural units (b1) represented by formula (1) as Z in formula (b) is preferably 2 to 45 mol%, more preferably 5 to 40%, still more preferably 10 to 40 mol%, and particularly preferably 15 to 35 mol%. When the total amount of the structural unit (a1) and the structural unit (b1) is not less than the above lower limit, the appearance quality and the elastic modulus of the optical film are easily improved. When the total amount of the structural unit (a1) and the structural unit (b1) is equal to or less than the upper limit, the total light transmittance of the optical film is easily improved. In the present specification, all structural units contained in the polyamideimide resin mean all monomer units contained in the polyamideimide resin. The amounts of the structural unit (a1), the structural unit (b1) and all the structural units contained in the polyamideimide resin may be used, for example1H-NMR, or the ratio of the raw materials charged may be calculated. Here, the total amount of the structural unit (a1) and the structural unit (b1) does not mean that both the structural unit (a1) and the structural unit (b1) are contained in the polyamideimide resin, and in the present invention, at least one of the structural unit (a1) and the structural unit (b1) may be contained in the polyamideimide resin. In the present invention, the polyamideimide resin contained in the optical film preferably contains at least the structural unit (a1) from the viewpoint of easily improving the appearance quality, total light transmittance and elastic modulus of the optical film of the present invention.
In a preferred embodiment of the present invention in which the polyamideimide resin contains the structural unit (a1) represented by the formula (1) wherein Y is represented by the formula (1), the amount of the structural unit (a1) is preferably 2 to 45 mol%, more preferably 5 to 40 mol%, further preferably 10 to 40 mol%, and particularly preferably 15 to 35 mol%, based on the total structural units contained in the polyamideimide resin. When the amount of the structural unit (a1) is not less than the above lower limit, the appearance quality and the elastic modulus of the optical film are easily improved. When the amount of the structural unit (a1) is not more than the upper limit, the total light transmittance of the optical film is easily improved. The amounts of the structural unit (a1), the structural unit (b1) and all the structural units contained in the polyamideimide resin may be set so thatBy e.g.1H-NMR, or the ratio of the raw materials charged may be calculated.
Formula (1) is preferably represented by formula (1').
[ chemical formula 21]
Figure BDA0003131483550000201
[ formula (1'), "represents a bond, R*A chemical bond in the case where Y is represented by formula (1), and a hydrogen atom in the case where Z is represented by formula (1)]
The formula (1') corresponds to R in the formula (1)aA hydrogen atom and n is 0.
In a preferred embodiment in which the polyamideimide resin contained in the optical film of the present invention contains the structural unit (a1) wherein Y in the formula (a) is represented by the formula (1), the polyamideimide resin contains at least the structural unit (b) derived from a dicarboxylic acid compound and the structural unit (c) derived from a diamine compound in addition to the structural unit (a 1). The polyamideimide resin in this embodiment may have 1 kind of the structural unit (b) and may have 2 or more kinds of the structural unit (b). The polyamideimide resin may have 1 kind of structural unit (c) or 2 or more kinds of structural units (c). Further, the tetracarboxylic acid compound may have a structural unit derived from a tetracarboxylic acid compound different from the structural unit (a1), or may have other structural units different from the structural units (a) to (c), such as a structural unit derived from a tricarboxylic acid compound.
In a preferred embodiment in which the polyamideimide resin contained in the optical film of the present invention contains the structural unit (b1) wherein Z in the formula (b) is represented by the formula (1), the polyamideimide resin contains at least the structural unit (a) derived from a tetracarboxylic acid compound and the structural unit (c) derived from a diamine compound in addition to the structural unit (b 1). The polyamideimide resin in this embodiment may have 1 kind of the structural unit (a), or may have 2 or more kinds of the structural unit (a). The polyamideimide resin may have 1 kind of structural unit (c) or 2 or more kinds of structural units (c). Further, the monomer may further have a structural unit derived from a dicarboxylic acid compound other than the structural unit (b1), or may have other structural units different from the structural units (a) to (c), such as a structural unit derived from a tricarboxylic acid compound.
In the polyamideimide resin contained in the optical film of the present invention, the amount of the structural unit (b) derived from the dicarboxylic acid compound is preferably 5 to 70 mol%, more preferably 10 to 65%, and even more preferably 20 to 60 mol%, based on the total structural units contained in the polyamideimide resin. When the amount of the structural unit (b) is not less than the above lower limit, the solubility of the resin in a solvent is easily improved, and the stability of the varnish is easily improved. When the amount of the structural unit (b) is not more than the above upper limit, the elastic modulus is easily increased. When the polyamideimide resin contains the structural unit (b1) as the structural unit (b) derived from the dicarboxylic acid compound, the total amount of the structural unit (b1) and other structural units derived from dicarboxylic acid (for example, the structural units (b2) and (b3) described later) other than the structural unit (b1) is preferably within the above range.
In the polyamideimide resin included in the optical film of the present invention, the amount of the structural unit (c) derived from the diamine compound is preferably 95 to 105 mol%, more preferably 97 to 103 mol%, even more preferably 98 to 102 mol%, and particularly preferably 99 to 101 mol%, based on 100 mol% of the total amount of the structural unit (a) derived from the tetracarboxylic acid compound and the structural unit (b) derived from the dicarboxylic acid compound. When the amount of the structural unit (c) is out of the above range, the molecular weight is less likely to increase, and the stability of the varnish tends to decrease.
In the present invention, the polyamideimide resin has a structural unit represented by the formula (b) as a structural unit (b) derived from a dicarboxylic acid compound.
[ chemical formula 22]
Figure BDA0003131483550000221
[ in the formula (b), Z represents a 2-valent organic group and represents a bond ]
Here, the formula (b) is a chemical bond connecting the structural unit (c) derived from a diamine compound, which is adjacent to the structural unit derived from a dicarboxylic acid compound in the polyamide imide resin in general. The structural unit (b) forms, for example, an amide bond represented by the above formula (E).
Z in the formula (b) is a 2-valent organic group, preferably a 2-valent organic group having 4 to 40 carbon atoms which may be substituted by a hydrocarbon group having 1 to 8 carbon atoms or a hydrocarbon group having 1 to 8 carbon atoms substituted with fluorine, more preferably a 2-valent organic group having 4 to 40 carbon atoms which may be substituted by a hydrocarbon group having 1 to 8 carbon atoms or a hydrocarbon group having 1 to 8 carbon atoms substituted with fluorine and has a cyclic structure. Examples of the cyclic structure include alicyclic, aromatic ring, and heterocyclic structure. Examples of Z include a 2-valent organic group obtained by replacing non-adjacent 2 of the chemical bonds of the groups represented by formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28), and formula (29) with a hydrogen atom, and a 2-valent chain hydrocarbon group having 6 or less carbon atoms, and examples of the heterocyclic structure of Z include a 2-valent organic group having a thiophene ring skeleton.
[ chemical formula 23]
Figure BDA0003131483550000231
From the viewpoint of easily reducing the YI value of the optical layered body, a 2-valent organic group obtained by replacing non-adjacent 2 of the chemical bonds of the groups represented by formulae (20) to (27) with hydrogen atoms, and a 2-valent organic group having a thiophene ring skeleton are preferable, and 2-valent organic groups represented by formulae (20 '), (21'), (22 '), (23'), (24 '), 25'), 26 '), 27', 28 ', and 29') are more preferable.
[ chemical formula 24]
Figure BDA0003131483550000232
The hydrogen atom on the ring in the formulae (20) to (29) and (20 ') to (29') may be substituted with an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, in which the hydrogen atom may be substituted with a halogen atom (preferably, a fluorine atom). In one embodiment of the present invention, Z in the structural unit (b) included in the polyamideimide resin may include 1 kind of organic group, or may include 2 or more kinds of organic groups.
In the formulae (20) to (29) and the formulae (20 ') to (29'),
denotes a chemical bond, W1Represents a single bond, -O-, -CH2-、-CH2-CH2-、-CH(CH3)-、-C(CH3)2-、-C(CF3)2-、-Ar3-、-SO2-、-CO-、-O-Ar3-O-、-Ar3-O-Ar3-、-Ar3-CH2-Ar3-、-Ar3-C(CH3)2-Ar3-or-Ar3-SO2-Ar3-。Ar3The arylene group having 6 to 20 carbon atoms, in which a hydrogen atom may be substituted with a fluorine atom, is exemplified by phenylene. Ar (Ar)3In case of plural, Ar3May be the same as or different from each other.
When the polyamideimide resin has a structural unit Z represented by any one of the above formulae (20 ') to (29 ') (hereinafter, also referred to as "structural units (b20 ') - (b29 ')") as the structural unit (b), it is preferable that the polyamideimide resin has a structural unit represented by the following formula (d1) (hereinafter, also referred to as "structural unit (d 1)") in addition to the structural unit (b ') from the viewpoint of easily improving the film-forming property of a varnish containing the resin and easily improving the uniformity of an optical film to be obtained.
[ chemical formula 25]
Figure BDA0003131483550000241
[ in the formula (d1), R24R is as defined in the formula (2-i) described later25Represents R24or-C (═ O) -, denotes a bond]
Specific examples of the structural unit (d1) include R24And R25Structural units each being a hydrogen atom, R24Are all hydrogen atoms and R25A structural unit representing-C (═ O) -, and the like.
The dicarboxylic acid compound providing the structural unit (b) is not particularly limited as long as it has 2 carbonyl groups, and examples thereof include compounds represented by the formula (b').
[ chemical formula 26]
Figure BDA0003131483550000242
[ formula (b'), wherein Z represents a 2-valent organic group, R31And R32Independently of one another, represents a hydroxyl group, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, a tert-butoxy group or a chlorine atom]
In the present invention, the structural unit (c) derived from a diamine compound of the polyamideimide resin is represented by the formula (c).
[ chemical formula 27]
Figure BDA0003131483550000251
[ in the formula (c), X represents a 2-valent organic group, RcIndependently of one another, represents a hydrogen atom or a chemical bond]
Here, the structural unit (c) represented by the formula (c) is generally adjacent to the structural unit (a) derived from a tetracarboxylic acid compound or the structural unit (b) derived from a dicarboxylic acid compound in the polyamideimide resin, and usually forms, for example, an imide bond represented by the formula (D) or an amide bond represented by the formula (E). In the structural unit (c), RcIndependently of each other representA hydrogen atom or a chemical bond. When one chemical bond represented by (a) is bonded to an adjacent structural unit derived from a tetracarboxylic acid compound, R is also represented by the formula (D)cRepresents a chemical bond and bonds to an adjacent structural unit derived from a tetracarboxylic acid. When one chemical bond represented by a in the structural unit (c) is bonded to an adjacent structural unit derived from a dicarboxylic acid compound, R is also known from the formula (E)cRepresents a hydrogen atom.
X in the formula (c) represents a 2-valent organic group, preferably a 2-valent organic group having 4 to 40 carbon atoms, and more preferably a 2-valent organic group having 4 to 40 carbon atoms and having a cyclic structure. Examples of the cyclic structure include alicyclic, aromatic ring, and heterocyclic structure. The organic group may have hydrogen atoms substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group, and in this case, the number of carbon atoms in the hydrocarbon group and the fluorine-substituted hydrocarbon group is preferably 1 to 8. In one embodiment of the present invention, X in the structural unit (c) included in the polyamideimide resin may include 1 type of 2-valent organic group, or may include 2 or more types of 2-valent organic groups.
The diamine compound providing the structural unit (c) is not particularly limited as long as it is a compound having 2 amino groups, and examples thereof include compounds represented by the formula (c').
[ chemical formula 28]
H2N-X-NH2 (c')
[ in the formula (c'), X represents a 2-valent organic group ]
In the polyamideimide resin contained in the optical film of the present invention, when a tetracarboxylic acid compound containing a structural unit represented by formula (1) (for example, a compound represented by formula (8)) is reacted with a diamine compound represented by formula (c'), for example, a structural unit represented by formula (10) can be formed. Further, for example, when the dicarboxylic acid compound represented by the formula (b ') is reacted with the diamine compound represented by the formula (c'), the structural unit represented by the formula (11) can be formed.
[ chemical formula 29]
Figure BDA0003131483550000261
[ in the formula (10), RaAnd n and R in the formula (1)aAnd n is as defined, X is as defined for X in formula (c), and represents a bond]
[ chemical formula 30]
Figure BDA0003131483550000262
[ in formula (11), Z is as defined for Z in formula (b), and X is as defined for X in formula (c), and represents a bond ]
In a preferred embodiment of the present invention, the polyamideimide resin contains a structural unit (b2) represented by the formula (2) as a structural unit (b) derived from a dicarboxylic acid compound in addition to at least one structural unit selected from the group consisting of the structural unit (a1) and the structural unit (b 1).
[ chemical formula 31]
Figure BDA0003131483550000263
[ in the formula (2), Z1Represents a 2-valent aromatic group which may have a substituent, the 2-valent aromatic group being a monocyclic aromatic ring or a condensed polycyclic aromatic ring, and represents a bond]
The polyamideimide resin generally has a plurality of structural units (b) represented by the formula (b). In this embodiment, at least a part of the plurality of structural units (b) may be the structural unit (b2) represented by formula (2). In this embodiment, the polyamideimide resin according to the present invention may have 1 kind of the structural unit (b2), 2 or more kinds of the structural unit (b2), or other structural unit (b) other than the structural unit (b2) as the structural unit (b).
Z in the formula (2)1Represents a 2-valent aromatic group which may have a substituent. The 2-valent aromatic group is a group in which 2 hydrogen atoms of a monocyclic aromatic ring or a condensed polycyclic aromatic ring are replaced with a chemical bondAnd (4) clustering. The 2-valent aromatic group may include an aromatic ring having a ring (monocyclic ring or condensed polycyclic ring) formed only by carbon atoms, or may include an aromatic heterocyclic ring having a ring formed so as to contain atoms other than carbon atoms. Examples of the atom other than carbon atoms include a nitrogen atom, a sulfur atom and an oxygen atom. The total number of carbon atoms and atoms other than carbon atoms forming the aromatic ring is not particularly limited, but is preferably 5 to 18, more preferably 5 to 14, further preferably 5 to 13, and particularly preferably 5 to 12.
Examples of the monocyclic aromatic ring include benzene, furan, pyrrole, thiophene, pyridine, imidazole, pyrazole, oxazole, thiazole, imidazoline, and the like.
Examples of the fused polycyclic aromatic ring include naphthalene, anthracene, phenanthrene, indole, benzothiazole, benzoxazole, benzimidazole, and the like.
From the viewpoint of facilitating improvement in appearance quality, elastic modulus, and total light transmittance of the optical film, the 2-valent aromatic group that may have a substituent is preferably a group in which 2 hydrogen atoms of an aromatic hydrocarbon ring are replaced with chemical bonds, more preferably a group in which 2 hydrogen atoms of benzene, biphenyl, terphenyl, or quaterphenyl are replaced with chemical bonds, even more preferably a group in which 2 hydrogen atoms of benzene or biphenyl are replaced with chemical bonds, and particularly preferably a group in which 2 hydrogen atoms of benzene are replaced with chemical bonds.
Z in the formula (2)1The 2-valent aromatic group may have a substituent. Examples of the substituent include at least one group selected from the group consisting of (i) an alkyl group having 1 to 12 carbon atoms, (ii) an alkoxy group having 1 to 12 carbon atoms, (iii) an aryl group having 6 to 12 carbon atoms, (iv) an aryloxy group having 6 to 12 carbon atoms, and (v) a hydroxyl group. The hydrogen atoms contained in the above-mentioned substituents may be independently substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, or a carboxyl group. The 2-valent aromatic group may have a C1-4 alkane group in which hydrogen atoms contained in the substituents selected from the group consisting of the substituents (i) to (v) and the substituents (i) to (v) are independently further substituted with a halogen atomAt least one substituent group selected from the group consisting of a group substituted with an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, or a carboxyl group, and may have no substituent group. Z in the formula (2) is Z from the viewpoint of ease of production of an optical film having a high modulus of elasticity1The 2-valent aromatic group represented preferably has no substituent.
Examples of (i) an alkyl group having 1 to 12 carbon atoms, (ii) an alkoxy group having 1 to 12 carbon atoms, and (iii) an aryl group having 6 to 12 carbon atoms include those directed to R in the formula (1)aThe above-exemplified groups, and the preferable descriptions concerning them, are also applicable to the above-mentioned groups.
Examples of (iv) the aryloxy group having 6 to 12 carbon atoms include a phenoxy group, a tolyloxy group, a xylyloxy group, a naphthyloxy group, and a biphenyloxy group. The number of carbon atoms of the aryloxy group having 6 to 12 carbon atoms is preferably 6, 10 or 12. The aryloxy group having 6 to 12 carbon atoms may be a group in which at least 1 hydrogen atom is independently substituted by a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, or a carboxyl group. Examples of the halogen atom include the atoms described above. Here, when the aryloxy group having 6 to 12 carbon atoms is substituted with a substituent containing a carbon atom, the number of carbon atoms contained in the substituent is not included in the number of carbon atoms of the aryloxy group having 6 to 12 carbon atoms.
In a preferred embodiment of the present invention in which the polyamideimide resin contains the structural unit (b2) represented by the formula (2) as the structural unit (b) derived from the dicarboxylic acid compound, the proportion of the structural unit (b2) represented by the formula (2) is preferably 70 to 100 mol%, more preferably 80 to 100 mol%, further preferably 90 to 100 mol%, and all the structural units (b) contained in the polyamideimide resin may be the structural unit (b2), from the viewpoint of easily improving the appearance quality of the optical film, and the total light transmittance and the elastic modulus. The content of the structural unit (b) and the structural unit (b2) can be used, for example1H-NMR, or from a sourceThe charge ratio of the materials was calculated.
In a preferred embodiment of the present invention in which the polyamideimide resin contains the structural unit (b2) in addition to at least one structural unit selected from the group consisting of the structural unit (a1) and the structural unit (b1), the structural unit (b2) represented by the formula (2) is more preferably represented by the following formula (2-i).
[ chemical formula 32]
Figure BDA0003131483550000291
[ in the formula (2-i), R24Independently represent a hydrogen atom, (i) an alkyl group having 1 to 12 carbon atoms, (ii) an alkoxy group having 1 to 12 carbon atoms, (iii) an aryl group having 6 to 12 carbon atoms, (iv) an aryloxy group having 6 to 12 carbon atoms or (v) a hydroxyl group, R24The hydrogen atoms contained in (A) may be substituted by halogen atoms, preferably hydrogen atoms, representing chemical bonds]
In this case, the polyamideimide resin has a structural unit represented by the formula (2-i) (hereinafter also referred to as "structural unit (b 2-i)"). In this embodiment, it is also preferable that the polyamideimide resin has the structural unit (d1) represented by the above formula (d1) in addition to the above structural unit (b2-i), from the viewpoint of easily improving the film formability of the varnish containing the resin and easily improving the uniformity of the optical film to be obtained.
In a preferred embodiment of the present invention, the polyamideimide resin contains the structural unit (c1) represented by the formula (3) as a structural unit derived from a diamine compound.
[ chemical formula 33]
Figure BDA0003131483550000292
[ in the formula (3), X1Represents an optionally substituted 2-valent aromatic group, RcIndependently of one another, represents a hydrogen atom or a chemical bond]
The polyamideimide-based resin generally has a plurality of structural units (c) represented by the formula (c). In this embodiment, at least a part of the plurality of structural units (c) may be the structural unit (c1) represented by formula (3). In this embodiment, the polyamideimide resin included in the optical film of the present invention may have 1 kind of structural unit (c1), 2 or more kinds of structural units (c1), and other structural units (c) other than the structural unit (c1) as the structural unit (c).
X in the formula (3)1Represents a 2-valent aromatic group which may have a substituent. The 2-valent aromatic group is a group in which 2 hydrogen atoms of a monocyclic aromatic ring, a condensed polycyclic aromatic ring, or a ring-assembly aromatic ring are replaced with a chemical bond. The 2-valent aromatic group may include an aromatic ring having a ring (a single ring, a condensed multiple ring, or a ring assembly) formed only of carbon atoms, or may include an aromatic heterocyclic ring having a ring formed so as to contain an atom other than carbon atoms. Examples of the atom other than carbon atoms include a nitrogen atom, a sulfur atom and an oxygen atom. The total number of carbon atoms and atoms other than carbon atoms forming the aromatic ring is not particularly limited, but is preferably 5 to 18, more preferably 5 to 14, further preferably 5 to 13, and particularly preferably 5 to 12. Examples of the monocyclic aromatic ring and the condensed polycyclic aromatic ring include Z in the formula (2)1But the examples described above. Examples of the aromatic ring assembly include structures in which 2 or more monocyclic aromatic rings and/or condensed polycyclic aromatic rings are connected by a single bond, and examples thereof include groups in which 2 or more of the rings described above as examples of the monocyclic aromatic rings or condensed polycyclic aromatic rings are connected by a single bond, such as biphenyl, terphenyl, tetrabiphenyl, binaphthyl, 1-phenylnaphthalene, 2-phenylnaphthalene, and bipyridine.
From the viewpoint of easily improving the appearance quality, elastic modulus, and total light transmittance of the optical film, the 2-valent aromatic group that may have a substituent is preferably a group in which 2 hydrogen atoms of an aromatic hydrocarbon ring that may have a substituent are replaced with chemical bonds, more preferably a group in which 2 hydrogen atoms of benzene, biphenyl, terphenyl, or quaterphenyl that may have a substituent are replaced with chemical bonds, even more preferably a group in which 2 hydrogen atoms of benzene or biphenyl that may have a substituent are replaced with chemical bonds, and particularly preferably a group in which 2 hydrogen atoms of biphenyl that may have a substituent are replaced with chemical bonds.
X in the formula (3)1The 2-valent aromatic group may have a substituent. Examples of the substituent include an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, a halogen group, and a group in which a hydrogen atom contained in the above groups is substituted with a halogen atom. Specific examples of the alkyl group having 1 to 12 carbon atoms, the alkoxy group having 1 to 6 carbon atoms, the aryl group having 6 to 12 carbon atoms, and the group in which a hydrogen atom contained in these groups is substituted with a halogen atom include Z in the formula (2)1The 2-valent aromatic group may have a substituent described for (i) an alkyl group having 1 to 12 carbon atoms, (ii) an alkoxy group having 1 to 12 carbon atoms, and (iii) an aryl group having 6 to 12 carbon atoms. Examples of the halo group include a fluoro group, a chloro group, a bromo group, and an iodo group.
As X in formula (3)1The substituent that the 2-valent aromatic group represented by (a) may have is preferably a halogen group or an alkyl group having 1 to 12 carbon atoms in which a hydrogen atom may be substituted with a halogen atom, and more preferably a methyl group, a fluoro group, a chloro group or a trifluoromethyl group.
In a preferred embodiment of the present invention, X in formula (3) is X from the viewpoint of easily improving the appearance quality, total light transmittance and elastic modulus of the optical film, and easily improving the stability of the varnish1Preferably represented by formula (4).
[ chemical formula 34]
Figure BDA0003131483550000311
[ in the formula (4), RbIndependently represent an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, RbThe hydrogen atoms in (A) may, independently of one another, be halogenThe r represents an integer of 1 to 4 independently of each other and represents a bond]
R in the formula (4)bIndependently represent an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, RbThe hydrogen atoms contained in (a) may be substituted by halogen atoms independently of each other. Examples of the alkyl group having 1 to 6 carbon atoms, the aryl group having 6 to 12 carbon atoms, and the alkoxy group having 1 to 6 carbon atoms include X in the formula (3)1The 2-valent aromatic group may have a substituent as exemplified above. R in the formula (4)bPreferably an alkyl group having 1 to 6 carbon atoms substituted with a halogen atom, more preferably a fluoroalkyl group having 1 to 6 carbon atoms, still more preferably a perfluoroalkyl group having 1 to 6 carbon atoms, yet more preferably a perfluoroalkyl group having 1 to 4 carbon atoms, particularly preferably a trifluoromethyl group or a pentafluoroethyl group, and particularly preferably a trifluoromethyl group.
R in the formula (4) independently represents an integer of 1 to 4, preferably 1 to 3, more preferably 1 to 2, and particularly preferably 1, from the viewpoint of easily improving the total light transmittance and the elastic modulus of the optical film.
In a preferred embodiment of the present invention, formula (4) is represented by formula (4').
[ chemical formula 35]
Figure BDA0003131483550000321
[ formula (4'), [ wherein R is16～R23Independently represent a hydrogen atom or a fluoroalkyl group having 1 to 6 carbon atoms, wherein R16～R19And R20～R23At least one of them represents a fluoroalkyl group having 1 to 6 carbon atoms and represents a chemical bond]
In the formula (4'), at least R is more preferably selected from the group consisting of18And R20Represents a fluoroalkyl group having 1 to 6 carbon atoms, and more preferably R18And R20Represents a fluoroalkyl group having 1 to 6 carbon atoms and R16、R17、R19、R21、R22And R23Represents a hydrogen atom. In the above aspect, the fluoroalkyl group having 1 to 6 carbon atoms is preferably a perfluoroalkyl group having 1 to 6 carbon atoms, more preferably a perfluoroalkyl group having 1 to 4 carbon atoms, still more preferably a trifluoromethyl group or a pentafluoroethyl group, and particularly preferably a trifluoromethyl group.
In a preferred embodiment of the present invention, formula (4') is represented by formula (4 ").
[ chemical formula 36]
Figure BDA0003131483550000322
[ in the formula (4') ] represents a chemical bond
The formula (4 ') corresponds to R in the formula (4')18And R20Represents a trifluoromethyl group, and R16、R17、R19、R21、R22And R23Represents a chemical formula of a hydrogen atom.
In a preferred embodiment of the present invention in which the polyamideimide resin contains the structural unit (c1) represented by the formula (3) as the structural unit (c) derived from the diamine compound, the proportion of the structural unit (c1) represented by the formula (3) is preferably 50 to 98 mol%, more preferably 60 to 95 mol%, and still more preferably 70 to 94 mol%, when the total of the structural units (c) contained in the polyamideimide resin is 100 mol%, from the viewpoints of easily improving the appearance quality of the optical film, and easily improving the total light transmittance and elastic modulus, and easily improving the stability of the varnish. A part of the structural unit (c) contained in the polyamideimide resin may be the structural unit (c1), or the entire structural unit (c) may be the structural unit (c1), but from the viewpoint of easily improving the appearance quality of the optical film, the total light transmittance and the elastic modulus, and easily improving the stability of the varnish, a part of the structural unit (c) contained in the polyamideimide resin is preferably the structural unit (c 1). To be explainedThe content of the structural unit (c) and the structural unit (c1) can be determined, for example1H-NMR, or the ratio of the raw materials charged may be calculated.
From the viewpoint of easily improving the appearance quality of the optical film, the total light transmittance and the elastic modulus, and easily improving the stability of the varnish, the polyamideimide resin contained in the optical film of the present invention preferably contains the structural unit (a1) represented by formula (1) for Y in formula (a) as a structural unit derived from a tetracarboxylic acid compound, contains the structural unit (b1) represented by formula (2) as a structural unit derived from a dicarboxylic acid compound, and contains the structural unit (c1) represented by formula (3) as a structural unit derived from a diamine compound.
In a preferred embodiment of the present invention, the polyamideimide resin further comprises at least one structural unit selected from the group consisting of a structural unit wherein Z in the formula (b) is represented by the formula (5), a structural unit wherein X in the formula (c) is represented by the formula (5), and a structural unit wherein Y in the formula (a) is represented by the formula (6).
[ chemical formula 37]
Figure BDA0003131483550000331
[ formula (5) wherein Ar is1Independently of each other, a 2-valent aromatic group which may have a substituent,
v represents a single bond, -O-, diphenylmethylene, a linear, branched or alicyclic 2-valent hydrocarbon group having 1 to 12 carbon atoms, or-SO2-, -S-, -CO-or-N (R)12) -, wherein the hydrogen atoms contained in the hydrocarbon group independently of each other may be substituted by halogen atoms, R12Represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom,
m represents an integer of 1 to 3, wherein when m is 2 or 3, a plurality of V may be the same or different,
represents a chemical bond ]
[ chemical formula 38]
Figure BDA0003131483550000341
In [ formula (6), Ar2Independently of each other, a 3-valent aromatic group which may have a substituent,
s represents an integer of 0 to 2,
Ar1v and Ar for formula (5)1V and x are as defined, wherein when s is 2, there are a plurality of V and Ar1Each of which may be the same as or different from each other, wherein V in the formula (6) is not a single bond]
In the present specification, a structural unit represented by formula (5) Z in formula (b) that can be contained as a structural unit derived from a dicarboxylic acid compound is also referred to as "structural unit (b 3)", a structural unit represented by formula (5) X in formula (c) that can be contained as a structural unit derived from a diamine compound is also referred to as "structural unit (c 2)", and a structural unit represented by formula (6) Y in formula (a) that can be contained as a structural unit derived from a tetracarboxylic acid compound is also referred to as "structural unit (a 2)". The polyamideimide resin contained in the optical film of the present invention has at least one structural unit (preferably, structural unit (a1)) selected from the group consisting of structural unit (a1) and structural unit (b1), and in a preferred embodiment, further contains at least one structural unit selected from the group consisting of structural unit (b3), structural unit (c2), and structural unit (a 2). In this embodiment, in addition to the structural unit represented by formula (1), at least one structural unit selected from the group consisting of the structural unit represented by formula (5) and the structural unit represented by formula (6) is also included in the polyamideimide resin. Note that structural unit (b3) is included as structural unit (b), structural unit (c2) is included as structural unit (c), and structural unit (a2) is included as structural unit (a). When the polyamideimide resin includes the structural unit (b3) as the structural unit (b), the resin may include the structural unit (b1), may include the structural unit (b2), may include the structural units (b1) and (b2), or may not include the structural units (b1) and (b 2). When the polyamideimide resin contains the structural unit (c2) as the structural unit (c), the resin may contain the structural unit (c1) or may not contain the structural unit (c 1).
Here, the structural unit represented by the formula (5) and the structural unit represented by the formula (6) each contain a 2-valent hydrocarbon group which represents a single bond (wherein V in the formula (6) is not a single bond), -O-, a diphenylmethylene group, a linear, branched or alicyclic group having 1 to 12 carbon atoms, -SO2-, -S-, -CO-or-N (R)12) The 2-valent linking group V of (E) is therefore a structure with high flexibility. When the polyamideimide resin further includes a structure having high flexibility as described above, the intermolecular interaction of the polyamideimide resin is easily reduced. As a result, the optical properties of the optical film containing the polyamideimide resin can be easily improved. In addition, the stability of the polyamideimide resin in the varnish state is also easily improved.
When the polyamideimide resin has at least one structural unit selected from the group consisting of the structural unit (b2) derived from a dicarboxylic acid compound represented by formula (5) for Z in formula (b), the structural unit (c2) derived from a diamine compound represented by formula (5) for X in formula (c), and the structural unit (a2) derived from a tetracarboxylic acid compound represented by formula (6) for Y in formula (a), the total amount of the structural unit (b2), the structural unit (c2), and the structural unit (a2) is preferably 1 to 25 mol%, more preferably 2 to 20 mol%, and still more preferably 3 to 15 mol%, based on all the structural units contained in the polyamideimide resin. When the total amount is within the above range, the stability of the varnish is easily improved, and the processability and total light transmittance of the optical film are easily improved. In this embodiment, the total amount of the structural unit (b2), the structural unit (c2), and the structural unit (a2) does not mean that the polyamideimide resin has all of the 3 types of structural units, and the polyamideimide resin may have at least 1 type of structural unit selected from the group consisting of the structural unit (b2), the structural unit (c2), and the structural unit (a 2).
When the polyamideimide resin has at least one structural unit selected from the group consisting of the structural unit (b2), the structural unit (c2), and the structural unit (a2), the total molar amount of the structural unit (b2), the structural unit (c2), and the structural unit (a2) is preferably 0.01 to 1.0 mol, more preferably 0.02 to 0.50 mol, and still more preferably 0.05 to 0.20 mol, when the total amount of the structural unit (a1) in which Y in the formula (a) is represented by the formula (1) and the structural unit (b1) in which Z in the formula (b) is represented by the formula (1) contained in the polyamideimide resin is 1 mol. When the total molar amount is not less than the above lower limit, the solubility in the varnish is easily improved. When the total molar amount is not more than the upper limit, the elastic modulus is easily increased. In this embodiment, the total molar amount does not mean that the polyamideimide resin has all of these structural units.
Ar in the formulae (5) and (6)1Represents a 2-valent aromatic group which may have a substituent. The 2-valent aromatic group is a group in which 2 hydrogen atoms of a monocyclic aromatic ring, a condensed polycyclic aromatic ring, or a ring-assembly aromatic ring are replaced with a chemical bond. The 2-valent aromatic group may include an aromatic ring having a ring (a single ring, a condensed multiple ring, or a ring assembly) formed only of carbon atoms, or may include an aromatic heterocyclic ring having a ring formed so as to contain an atom other than carbon atoms. Examples of the atom other than carbon atoms include a nitrogen atom, a sulfur atom and an oxygen atom. The total number of carbon atoms and atoms other than carbon atoms forming the aromatic ring is not particularly limited, but is preferably 5 to 18, more preferably 5 to 14, further preferably 5 to 13, and particularly preferably 5 to 12. Examples of monocyclic aromatic ring, condensed polycyclic aromatic ring and ring-fused aromatic ring include those for Z in the formula (2)1But the examples described above.
From the viewpoint of easily improving the elastic modulus and the total light transmittance of the optical film, the 2-valent aromatic group which may have a substituent is preferably a group in which 2 hydrogen atoms of an aromatic hydrocarbon ring are replaced with chemical bonds, more preferably a group in which 2 hydrogen atoms of benzene, biphenyl, terphenyl, or quaterphenyl are replaced with chemical bonds, and even more preferably a group in which 2 hydrogen atoms of benzene or biphenyl are replaced with chemical bonds.
Ar in the formulae (5) and (6)1The 2-valent aromatic group may have a substituent. Examples of the substituent include (i) an alkyl group having 1 to 12 carbon atoms, (ii) an alkoxy group having 1 to 12 carbon atoms, (iii) an aryl group having 6 to 12 carbon atoms, (iv) an aryloxy group having 6 to 12 carbon atoms, (v) a carbonyl group having 1 to 12 carbon atoms, (vi) an oxycarbonyl group having 1 to 12 carbon atoms, and (vii) a halogeno group. The hydrogen atoms contained in the above-mentioned substituents may be independently substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, or a carboxyl group. The 2-valent aromatic group may have at least 1 of the substituents (i) to (vii) above, and a group in which at least 1 hydrogen atom contained in the substituents (i) to (vii) above is independently substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, or a carboxyl group, or may have no substituent. Ar in the formulae (5) and (6) is selected from the viewpoint of ease of production of an optical film having a high elastic modulus1The 2-valent aromatic group represented preferably has no substituent.
Examples of (i) an alkyl group having 1 to 12 carbon atoms, (ii) an alkoxy group having 1 to 12 carbon atoms, (iii) an aryl group having 6 to 12 carbon atoms and (iv) an aryloxy group having 6 to 12 carbon atoms include those related to Z in the formula (2)1The 2-valent aromatic group may have a substituent as exemplified above.
(v) The carbonyl group having 1 to 12 carbon atoms is-CO-Rdor-Re-CO-RdThe group shown. As RdExamples of the group include (i) a group described for an alkyl group having 1 to 12 carbon atoms as ReExamples of the alkylene group include (i) a 2-valent alkylene group having 1 to 12 carbon atoms, in which at least 1 hydrogen atom of the group described in the alkyl group having 1 to 12 carbon atoms is replaced with a chemical bond. The carbonyl group having 1 to 12 carbon atoms may be a group in which at least 1 hydrogen atom is independently substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, or a carboxyl group. Examples of the halogen atom include those described aboveA carried atom. When the carbonyl group having 1 to 12 carbon atoms is substituted with a substituent containing a carbon atom, the number of carbon atoms contained in the substituent is not included in the number of carbon atoms of the carbonyl group having 1 to 12 carbon atoms.
(vi) The oxycarbonyl group having 1 to 12 carbon atoms is-CO-O-Rd、*-Re-CO-O-Rd、*-O-CO-Rdor-Re-O-CO-RdThe group shown. As RdExamples of the group include (i) a group described for an alkyl group having 1 to 12 carbon atoms as ReExamples of the alkylene group include (i) a 2-valent alkylene group having 1 to 12 carbon atoms, in which at least 1 hydrogen atom of the group described in the alkyl group having 1 to 12 carbon atoms is replaced with a chemical bond. The oxycarbonyl group having 1 to 12 carbon atoms may be a group in which at least 1 hydrogen atom is independently substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, or a carboxyl group. Examples of the halogen atom include the atoms described above. Here, when the oxycarbonyl group having 1 to 12 carbon atoms is substituted with a substituent containing a carbon atom, the number of carbon atoms contained in the substituent is not included in the number of carbon atoms of the oxycarbonyl group having 1 to 12 carbon atoms.
Examples of the (vii) halogeno group include a fluoro group, a chloro group, a bromo group and an iodo group.
Ar in formula (6)2Represents a 3-valent aromatic group which may have a substituent. The 3-valent aromatic group is a group in which 3 hydrogen atoms of a monocyclic aromatic ring, a condensed polycyclic aromatic ring, or a ring-assembly aromatic ring are replaced with a chemical bond. The 3-valent aromatic group may include an aromatic ring having a ring (a single ring, a condensed multiple ring, or a ring assembly) formed only of carbon atoms, or may include an aromatic heterocyclic ring having a ring formed so as to contain an atom other than carbon atoms. Examples of the atom other than carbon atoms include a nitrogen atom, a sulfur atom and an oxygen atom. The total number of carbon atoms and atoms other than carbon atoms forming the aromatic ring is not particularly limited, but is preferably 5 to 18, more preferably 5 to 14, further preferably 5 to 13, and particularly preferably 5 to 12. As monocyclic aromatics in the 3-valent aromatic groupAromatic rings, condensed polycyclic aromatic rings, or ring-fused aromatic rings, for Ar mentioned above1The rings described. As the substituent that the 3-valent aromatic group may have, there may be mentioned Ar mentioned above1The substituent as described for Ar1The preferred descriptions mentioned apply equally to Ar2。
From the viewpoint of easily improving the appearance quality, elastic modulus, and total light transmittance of the optical film, the 3-valent aromatic group that may have a substituent is preferably a group in which 3 hydrogen atoms of an aromatic hydrocarbon ring are replaced with chemical bonds, more preferably a group in which 3 hydrogen atoms of benzene, biphenyl, terphenyl, or quaterphenyl are replaced with chemical bonds, and even more preferably a group in which 3 hydrogen atoms of benzene or biphenyl are replaced with chemical bonds.
When m in formula (5) is 1 or more, and when s in formula (6) is 2, a plurality of Ar's are present1May be the same as or different from each other. In addition, in formula (6), there are a plurality of Ar2May be the same as or different from each other.
M in formula (5) represents an integer of 1 to 3, and is preferably 1 or 2, more preferably 1, from the viewpoint of improving the elastic modulus and ensuring solubility in a varnish. In formula (5), x represents a bond.
S in formula (6) represents an integer of 0 to 2, and is preferably 0 or 1, and more preferably 0, from the viewpoint of ensuring solubility in the varnish and high transmittance. In formula (6), x represents a bond.
V in the formulas (5) and (6) represents a single bond (wherein V in the formula (6) is not a single bond), -O-, a diphenylmethylene group, a linear, branched or alicyclic 2-valent hydrocarbon group having 1 to 12 carbon atoms, -SO2-, -S-, -CO-or-N (R)12) -, wherein the hydrogen atoms contained in the hydrocarbon group independently of each other may be substituted by halogen atoms, R12Represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom. Examples of the linear, branched or alicyclic alkyl group having 1 to 12 carbon atoms include those for R in the formula (1)aThe alkyl group having 1 to 12 carbon atoms.
In formula (5) and formula (6), examples of V include a group in which at least 1 hydrogen atom of a linear, branched or alicyclic alkyl group having 1 to 12 carbon atoms is replaced with a chemical bond, as the linear, branched or alicyclic 2-valent hydrocarbon group having 1 to 12 carbon atoms. Examples of the linear, branched or alicyclic alkyl group having 1 to 12 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a 2-methyl-butyl group, a 3-methylbutyl group, a 2-ethyl-propyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, a tert-octyl group, an n-nonyl group, an n-decyl group, a cyclopentyl group, a cyclohexyl group and the like. The C1-12 divalent hydrocarbon group may be a linear alkylene group, a branched alkylene group, or an alicyclic alkylene group having an alicyclic hydrocarbon structure. The number of carbon atoms of the 2-valent hydrocarbon group having 1 to 12 carbon atoms is preferably 1 to 6, more preferably 1 to 4, and further preferably 1 to 3. The above-mentioned C1-12 hydrocarbon group having a valence of 2 may be a group in which at least 1 hydrogen atom is independently substituted with a halogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
In formulae (5) and (6), Ar1、Ar2And V, each of which may be the same or different, when a plurality of them are present, it is preferable that Ar is present in a plurality of the Ar groups from the viewpoint of easy synthesis of the polyamideimide resin1Same as each other, a plurality of Ar's are present2Are identical to each other, and/or there are a plurality of V's identical to each other.
In a preferred embodiment of the present invention, the formulae (5) and (6) are preferably represented by formula (7).
[ chemical formula 39]
Figure BDA0003131483550000391
[ in the formula (7), R1Independently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, R1Wherein the hydrogen atoms contained therein are independent of each otherThe earth may be substituted by a halogen atom,
R*represents R1Or a chemical bond to the substrate,
the symbol represents a chemical bond,
v represents a single bond (wherein V in the formula (6) is not a single bond), -O-, a diphenylmethylene group, a linear, branched or alicyclic 2-valent hydrocarbon group having 1 to 12 carbon atoms, -SO2-, -S-, -CO-or-N (R)12) -, wherein the hydrogen atoms contained in the hydrocarbon group independently of each other may be substituted by halogen atoms, R12Represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom]
When formula (5) is represented by formula (7), R is 2 bonds in formula (7), and thus R is*Represents R1. When formula (6) is represented by formula (7), R is 4 bonds in formula (7)*Represents a chemical bond. In addition, R in the formula (7)1And Ar in formula (5)1And Ar in formula (6)2The same applies to the description of the substituents which may be present, and the preferred description applies also. In addition, the same description applies to V in formula (7) as that in formula (5) and formula (6).
In a preferred embodiment of the present invention, when the polyamideimide resin contains, as a structural unit derived from a diamine compound, a structural unit (c2) wherein X in the formula (c) is represented by the formula (5) or the formula (7), or further contains, as a structural unit derived from a tetracarboxylic acid compound, a structural unit (a2) wherein Y in the formula (a) is represented by the formula (6) or the formula (7), V in the formula (5), the formula (6) or the formula (7) preferably represents-O-, diphenylmethylene, a linear, branched or alicyclic 2-valent hydrocarbon group having 1 to 12 carbon atoms, -SO2-, -S-, -CO-or-N (R)12) The compound is more preferably represented by-O-, diphenylmethylene, a linear, branched or alicyclic 2-valent hydrocarbon group having 1 to 12 carbon atoms, or a 2-valent hydrocarbon group having 1 to 12 carbon atoms, wherein a hydrogen atom contained in the 2-valent hydrocarbon group is substituted with a halogen atomThe group (b) is more preferably a group in which a hydrogen atom contained in a 2-valent hydrocarbon group having 1 to 12 carbon atoms or a 2-valent hydrocarbon group having 1 to 12 carbon atoms is substituted with a halogen atom.
In this embodiment, V in the formulae (5), (6) and (7) is more preferably a group in which at least 1 hydrogen atom of a linear, branched or alicyclic alkylene group having 1 to 12 carbon atoms is substituted with a halogen atom (preferably a fluorine atom) (preferably a fluoroalkylene group having 1 to 12 carbon atoms), and still more preferably a group in which all hydrogen atoms of a linear, branched or alicyclic alkylene group having 1 to 12 carbon atoms are substituted with a halogen atom (preferably a fluorine atom) (preferably a perfluoroalkylene group having 1 to 12 carbon atoms, and particularly preferably a bistrifluoromethylmethylene group).
In this embodiment, the formula (7) is preferably represented by formula (7 ') or formula (7').
[ chemical formula 40]
Figure BDA0003131483550000411
[ formula (7') wherein R*Represents a hydrogen atom or a chemical bond]
[ chemical formula 41]
Figure BDA0003131483550000412
[ in the formula (7'), represents a chemical bond ]
When the polyamideimide resin further contains a structural unit (a2) in which Y in formula (a) is represented by formula (6) as a structural unit derived from a tetracarboxylic acid compound, and when a structural unit (c2) in which X in formula (c) is represented by formula (5) as a structural unit (c) derived from a diamine compound, formula (5) is preferably represented by formula (7), and more preferably formula (7) is represented by formula (7'). When the polyamideimide resin contains the structural unit (b3) in which Z in the formula (b) is represented by the formula (5) as a structural unit derived from a dicarboxylic acid compound, the formula (5) is preferably represented by the formula (7), and the formula (7) is more preferably represented by the formula (7 ").
In a preferred embodiment of the present invention, the polyamideimide resin has the above-mentioned structural unit (a1), structural unit (b), and structural unit (c), and further has a structural unit (a2) derived from a tetracarboxylic acid compound, wherein Y in formula (a) is represented by formula (6). In this case, the amount of the structural unit (a2) is preferably 1 to 25 mol%, more preferably 2 to 20 mol%, and still more preferably 3 to 15 mol%, based on the total structural units contained in the polyamideimide resin. When the amount of the structural unit (a2) is within the above range, the appearance quality of the optical film is easily improved, the stability of the varnish is easily improved, and the processability and the total light transmittance of the optical film are easily improved.
In another preferred embodiment of the present invention, the polyamideimide resin has the above-mentioned structural unit (a1) and structural unit (b), and further has a structural unit (c2) in which X in formula (c) is represented by formula (5) as the structural unit (c) derived from a diamine compound. In this embodiment, at least a part of the plurality of structural units (c) present in the polyamideimide resin may be the structural unit (c 2). When the polyamideimide resin includes at least the structural unit (a1), the structural unit (b), and the structural unit (c2), the amount of the structural unit (c2) is preferably 1 to 25 mol%, more preferably 2 to 20 mol%, and still more preferably 3 to 15 mol%, based on the total structural units contained in the polyamideimide resin. When the amount of the structural unit (c2) is within the above range, the stability of the varnish is easily improved, and the processability and total light transmittance of the optical film are easily improved.
In a preferred embodiment of the present invention, when the polyamideimide resin contains, as a structural unit derived from a dicarboxylic acid compound, a structural unit (b3) in which Z in the formula (b) is represented by the formula (5) or the formula (7), V in the formula (5) or the formula (7) preferably represents a group in which a hydrogen atom contained in a linear, branched or alicyclic 2-valent hydrocarbon group having 1 to 12 carbon atoms or a 2-valent hydrocarbon group having 1 to 12 carbon atoms is substituted with a halogen atom, more preferably represents-O-, from the viewpoints of the elastic modulus, the total light transmittance, the surface hardness and the bending resistance of an optical film and the stability of a varnish.
In this embodiment, the formula (5) is preferably represented by formula (9).
[ chemical formula 42]
Figure BDA0003131483550000421
[ formula (9) wherein R4～R11Independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, R4～R11The hydrogen atoms contained in (a) may be substituted independently of each other by halogen atoms,
m is an integer of 1 to 4,
represents a chemical bond ]
R in the formula (9)4～R11Independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, R4～R11The hydrogen atoms contained in (a) may be substituted by halogen atoms independently of each other. Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a 2-methyl-butyl group, a 3-methylbutyl group, a 2-ethyl-propyl group, and an n-hexyl group. Examples of the alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, a propyloxy group, an isopropyloxy group, a butoxy group, an isobutoxy group, a tert-butoxy group, a pentyloxy group, a hexyloxy group, a cyclohexyloxy group, and the like. Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and a biphenyl group. From the viewpoint of surface hardness and flexibility of the optical film, R4～R11Independently of each other, the alkyl group preferably represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and still more preferably represents a hydrogen atom. Here, R4～R11The hydrogen atoms contained in (a) may be substituted by halogen atoms independently of each other. As the aforementioned halogen atom, may be mentionedExamples thereof include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like.
When m in the formula (9) is an integer of 1 to 4, and m is within this range, the optical film tends to have good bending resistance and good elastic modulus. In addition, m in the formula (9) is preferably an integer in the range of 1 to 3, more preferably 1 to 2, and even more preferably 1. When m is within this range, the appearance quality, bending resistance and elastic modulus of the optical film are easily improved. In the case where the polyamideimide resin of the present invention has a structural unit wherein Z in the formula (b) is represented by the formula (9) as the structural unit (b) derived from a dicarboxylic acid compound, the polyamideimide resin may have 1 or 2 or more structural units wherein Z in the formula (b) is represented by the formula (9).
In this embodiment, the formula (9) is preferably represented by formula (7 ").
[ chemical formula 43]
Figure BDA0003131483550000431
In this case, the appearance quality, surface hardness, and bending resistance of the optical film are easily improved, and the YI value is easily reduced.
When the polyamideimide resin contains the structural unit (b3) in which Z in the formula (b) is represented by the formula (5), the formula (7), the formula (9) or the formula (7 ") as the structural unit (b) derived from the dicarboxylic acid compound, the proportion of the structural unit (b3) is preferably 1 mol% or more, more preferably 2 mol% or more, further preferably 3 mol% or more, particularly preferably 4 mol% or more, preferably 45 mol% or less, more preferably 35 mol% or less, further preferably 25 mol% or less, particularly preferably 15 mol% or less, when the amount of all the structural units contained in the polyamideimide resin is taken as 100 mol%. When the proportion of the structural unit (b3) is not less than the above lower limit, the appearance quality, surface hardness and bending resistance of the optical film are easily improved. When the ratio is not more than the upper limit, the viscosity of the varnish containing the resin is easily prevented from increasing, and the film processability is easily improved. It is to be noted that the content of these structural units may be, for example, the one1H-NMR, or calculated from the charge ratio of the raw materials.
In a preferred embodiment of the present invention, when the polyamideimide resin contains, as the structural unit (b) derived from the dicarboxylic acid compound, a structural unit (b3) in which Z in the formula (b) is represented by the formula (5), the formula (7), the formula (9) or the formula (7 ″), preferably 5 mol% or more, more preferably 8 mol% or more, further preferably 10 mol% or more, and particularly preferably 12 mol% or more of the structural units (b) is the structural unit (b 3). When the amount of the structural unit (b3) is within the above range, the surface hardness of the optical film is easily increased, and the bending resistance and the elastic modulus are easily increased. In addition, it is preferable that 90 mol% or less, more preferably 70 mol% or less, still more preferably 50 mol% or less, and particularly preferably 30 mol% or less of the constituent unit (b) derived from the dicarboxylic acid compound contained in the polyamideimide resin is the constituent unit (b 3). When the amount of the structural unit (b3) is within the above range, the viscosity of the varnish containing the resin is easily inhibited from increasing, and the film processability is improved. Preferably, the polyamideimide resin contained in the optical film of the present invention has the above structural unit (a1), and contains the above amount of the structural unit (b3) as the structural unit (b) derived from the dicarboxylic acid compound, and has the above structural unit (b2) as the other structural unit (b).
As described above, in the polyamideimide-based resin contained in the optical film of the present invention,
a structural unit (a1) wherein Y in formula (a) is represented by formula (1), a structural unit (b) represented by formula (b), and a structural unit (c) represented by formula (c),
a structural unit (a) represented by formula (a), a structural unit (b1) represented by formula (1) wherein Z in formula (b) is represented by formula (1), and a structural unit (c) represented by formula (c) or,
at least a structural unit (a1) in which Y in formula (a) is represented by formula (1), a structural unit (b1) in which Z in formula (b) is represented by formula (1), and a structural unit (c) in which Z is represented by formula (c) are contained.
In a preferred embodiment of the present invention, from the viewpoint of easily improving the stability of the varnish and easily improving the appearance quality, total light transmittance, elastic modulus, surface hardness, and bending resistance of the optical film to be obtained, examples of preferred polyamideimide resins to be included in the optical film of the present invention include the following resins:
(i) a polyamideimide resin comprising at least a structural unit (a1), a structural unit (b1) wherein Z in the formula (b) is represented by the formula (2), and a structural unit (c),
(ii) a polyamideimide resin comprising at least a structural unit (a1), a structural unit of a 2-valent organic group obtained by replacing non-adjacent 2 of chemical bonds of the groups represented by the formulae (20) to (29) wherein Z in the formula (b) represents a hydrogen atom, or a 2-valent organic group having a thiophene ring skeleton, and a structural unit (c),
(iii) a polyamideimide resin comprising at least a structural unit (a1), at least one of structural units (20b ') to (b 29') wherein Z in formula (b) represents a 2-valent organic group represented by formulae (20 ') to (29'), and a structural unit (c),
(iv) a polyamideimide resin comprising at least a structural unit (a1), at least one of the structural units (20b ') to (b 29'), a structural unit (c), and a structural unit (d1) represented by the formula (d1),
(v) a polyamideimide resin comprising at least a structural unit (a1), a structural unit (b2-i) represented by the formula (2-i) and a structural unit (c),
(vi) a polyamideimide resin comprising at least a structural unit (a1), a structural unit (b2-i), a structural unit (c), and a structural unit (d1),
(viii) the structural unit (c) in each of the above-mentioned polyamideimide resins is a polyamideimide resin containing at least a structural unit (c1) wherein X in the formula (c) is represented by the formula (3),
(ix) each of the above-mentioned polyamideimide resins comprises a structural unit selected from the group consisting of a structural unit (a2) wherein Y in formula (a) is represented by formula (6) as at least a part of structural unit (a), a structural unit (b3) wherein Z in formula (b) is represented by formula (5) as at least a part of structural unit (b), and a structural unit (c2) wherein X in formula (c) is represented by formula (5) as at least a part of structural unit (c),
(x) Each of the above-mentioned polyamideimide resins includes the structural unit (a) in place of the structural unit (a1) and also includes the structural unit (b 1).
From the viewpoint of easily improving the varnish stability of the polyamideimide resin, and easily improving the appearance quality, total light transmittance, elastic modulus, surface hardness, and bending resistance of the optical film obtained, it is preferable that the polyamideimide resin has, in addition to the structural unit (a1) in which Y in formula (a) is represented by formula (1), a structural unit (c1) and a structural unit (b2), or at least one of structural units (a2), (b3), and (c2), and more preferably at least one of structural units (a2), (b3), and (c2) in addition to the structural unit (a1) in which Y in formula (a) is represented by formula (1), structural units (c1) and (b 2). When the polyamideimide resin has at least one of the structural units (a2), (b3) and (c2), it preferably has at least the structural unit (c 2). The polyamideimide resin of the present invention preferably has any one of the structural units (b20 ') to (b 29') and has the structural unit (d1), more preferably has the structural unit (b2) and has the structural unit (d1), in addition to the structural unit (a1) and the structural unit (c).
In the polyamideimide resin included in the optical film of the present invention, the structural unit (a), the structural unit (b) and the structural unit (c) may form a structure including the imide bond represented by the above formula (D) and the amide bond represented by the above formula (E), but in addition to the structures represented by the formulae (D) and (E), for example, the structural unit (a) and the structural unit (c) may be included so as to form a structure represented by the formula (30), or the structural unit (D) different from the structural units (a) to (c) and the structural unit (c) may be included so as to form a structural unit represented by the formula (31).
[ chemical formula 44]
Figure BDA0003131483550000471
In the formula (30), Y1Is a 4-valent organic group, and is,preferred are 4-valent organic groups in which a hydrogen atom in an organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. Y is1For example, the structural unit represented by the formula (1) may be used. In one embodiment of the present invention, the polyamideimide-based resin may include a plurality of Y' s1Plural kinds of Y1May be the same as or different from each other.
In the formula (31), Y2Is a 3-valent organic group, preferably a 3-valent organic group in which a hydrogen atom in the organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. In one embodiment of the present invention, the polyamideimide-based resin may include a plurality of Y' s2Plural kinds of Y2May be the same as or different from each other.
In the formulae (30) and (31), X2And X3Independently of one another, are 2-valent organic groups, preferably organic groups in which the hydrogen atoms of the organic groups can be replaced by hydrocarbon groups or fluorine-substituted hydrocarbon groups. As X2And X3Examples thereof may include a group represented by X in the formula (c) and a group represented by X' in the formula (2).
In one embodiment of the present invention, the polyamideimide resin includes a structural unit represented by formula (D) composed of a structural unit (a) derived from a tetracarboxylic acid compound and a structural unit (c) derived from a diamine compound, a structural unit represented by formula (E) composed of a structural unit (b) derived from a dicarboxylic acid compound and a structural unit (c) derived from a diamine compound, and optionally a structural unit represented by formula (30) and/or a structural unit represented by formula (31). From the viewpoint of easily improving the elastic modulus, the total light transmittance, the optical properties, and the surface hardness of the optical film, the structural units represented by the formulae (D) and (E) are contained in the polyamideimide resin in an amount of preferably 80 mol% or more, more preferably 90 mol% or more, and still more preferably 95 mol% or more, based on the total of the structural units represented by the formulae (D) and (E) and, in some cases, the structural units represented by the formulae (30) and (31), and usually 100 mol% or less. The above ratio can be used, for example1H-NMR, or the ratio of the raw materials charged may be calculated.
The polyamide imide resin contained in the optical film of the present invention has a weight average molecular weight in terms of polystyrene of preferably 200,000 or more, more preferably 250,000 or more, further preferably 300,000 or more, and particularly preferably 350,000 or more, from the viewpoint of easily improving the stability of the varnish and easily improving the optical properties, elastic modulus, surface hardness, and bending resistance of the optical film. The weight average molecular weight is preferably 1,000,000 or less, more preferably 800,000 or less, further preferably 700,000 or less, and particularly preferably 600,000 or less, from the viewpoint of easily improving the solubility of the polyamideimide resin in a solvent and easily improving the stretchability and processability of the optical film. The weight average molecular weight can be determined by GPC measurement and conversion to standard polystyrene, for example, and can be calculated by the method described in examples.
The imidization ratio of the polyamide imide resin is preferably 90% or more, more preferably 93% or more, further preferably 96% or more, and usually 100% or less. The imidization ratio is preferably not less than the above-described lower limit from the viewpoint of easily improving the optical properties of the optical film. The imidization ratio represents a ratio of a molar amount of imide bonds in the polyamideimide resin to a value 2 times as large as a molar amount of a structural unit derived from a tetracarboxylic acid compound in the polyamideimide resin. When the polyamideimide resin contains a tricarboxylic acid compound, it means a ratio of a molar amount of imide bonds in the polyamideimide resin relative to a total of a value 2 times as large as a molar amount of a structural unit derived from a tetracarboxylic acid compound in the polyamideimide resin and a molar amount of a structural unit derived from a tricarboxylic acid compound. The imidization ratio can be determined by an IR method, an NMR method or the like.
The content of the halogen atom in the polyamideimide resin is preferably 1 to 40% by mass, more preferably 5 to 40% by mass, and still more preferably 5 to 30% by mass, based on the mass of the polyamideimide resin. When the content of the halogen atom is not less than the above lower limit, the elastic modulus, the surface hardness, the transparency, and the visibility of the optical film are more easily improved. When the content of the halogen atom is not more than the above upper limit, the synthesis of the resin becomes easy.
[ method for producing resin ]
The polyamideimide resin included in the optical film of the present invention can be produced using a tetracarboxylic acid compound, a dicarboxylic acid compound and a diamine compound as main raw materials. Here, the polyamideimide resin contains at least one structural unit selected from the group consisting of a structural unit (a1) in which Y in formula (a) is represented by formula (1) as a structural unit derived from a tetracarboxylic acid compound and a structural unit (b1) in which Z in formula (b) is represented by formula (1) as a structural unit derived from a dicarboxylic acid compound. Therefore, at least one compound selected from the group consisting of a tetracarboxylic acid compound having a structure represented by formula (1) and a dicarboxylic acid compound having a structure represented by formula (1) is used as a raw material.
Examples of the tetracarboxylic acid compound that can be used for producing the resin include tetracarboxylic acid compounds that provide the structural unit (a1) represented by formula (1) for Y in formula (a), and aromatic tetracarboxylic acid compounds such as aromatic tetracarboxylic acid dianhydrides. 1 tetracarboxylic acid compound may be used, or 2 or more tetracarboxylic acid compounds may be used in combination. The tetracarboxylic acid compound may be a tetracarboxylic acid compound analog such as an acid chloride compound, in addition to the dianhydride. For example, the compound represented by the above formula (8) can be mentioned.
Examples of the tetracarboxylic acid compound that can be used for producing the resin include a compound represented by the above formula (8) (tetracarboxylic dianhydride), for example, 3 ', 4, 4' -biphenyltetracarboxylic dianhydride (BPDA).
Further, other tetracarboxylic acid compounds that can be used for producing the resin include 4,4 '-oxydiphthalic anhydride (4, 4' -oxydiphthalic dianhydride), 2', 3, 3' -benzophenone tetracarboxylic acid dianhydride, 2', 3, 3' -biphenyl tetracarboxylic acid dianhydride, 3,3 ', 4, 4' -diphenylsulfone tetracarboxylic acid dianhydride, 2-bis (3, 4-dicarboxyphenyl) propane dianhydride, 2-bis (2, 3-dicarboxyphenyl) propane dianhydride, 2-bis (3, 4-dicarboxyphenoxyphenyl) propane dianhydride, 4,4 '- (hexafluoroisopropylidene) diphthalic anhydride (4, 4' - (hexafluoroisopropylidene) diphthalic dianhydride, which may be described as 6FDA), 1, 2-bis (2, 3-dicarboxyphenyl) ethane dianhydride, 1,4 '-oxydiphthalic dianhydride, 2' -bis (3-dicarboxyphenyl) ethane dianhydride, and the like, 1, 1-bis (2, 3-dicarboxyphenyl) ethane dianhydride, 1, 2-bis (3, 4-dicarboxyphenyl) ethane dianhydride, 1-bis (3, 4-dicarboxyphenyl) ethane dianhydride, bis (3, 4-dicarboxyphenyl) methane dianhydride, bis (2, 3-dicarboxyphenyl) methane dianhydride, 4 '- (p-phenylenedioxy) diphthalic anhydride, 4' - (m-phenylenedioxy) diphthalic anhydride. Examples of the monocyclic aromatic tetracarboxylic acid dianhydride include 1,2,4, 5-benzenetetracarboxylic acid dianhydride (pyromellitic dianhydride (PMDA)), and examples of the condensed polycyclic aromatic tetracarboxylic acid dianhydride include 2,3,6, 7-naphthalenetetracarboxylic acid dianhydride.
Of these, preferred tetracarboxylic acid compounds include 4,4 ' -oxydiphthalic anhydride, 3,3 ', 4,4 ' -benzophenonetetracarboxylic dianhydride, 2', 3,3 ' -benzophenonetetracarboxylic dianhydride, 3,3 ', 4,4 ' -biphenyltetracarboxylic dianhydride (BPDA), 1,2,4, 5-benzenetetracarboxylic dianhydride (PMDA), 2', 3,3 ' -biphenyltetracarboxylic dianhydride, 3,3 ', 4,4 ' -diphenylsulfonetetracarboxylic dianhydride, 2-bis (3, 4-dicarboxyphenyl) propane dianhydride, 2-bis (2, 3-dicarboxyphenyl) propane dianhydride, 2-bis (3, 4-dicarboxyphenoxyphenyl) propane 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-bis (3, 4-dicarboxyphenyl) ethane dianhydride, bis (3, 4-dicarboxyphenyl) methane dianhydride, bis (2, 3-dicarboxyphenyl) methane dianhydride, 4,4 '- (terephthaloxy) bisphthalic anhydride and 4, 4' - (m-phenylenedioxy) bisphthalic anhydride, more preferably 4,4 '-oxydiphthalic anhydride, 3, 3', 4,4 '-biphenyltetracarboxylic dianhydride (BPDA), 2', 3,3 '-biphenyltetracarboxylic dianhydride, bis (3, 4-dicarboxyphenyl) methane dianhydride, 4, 4' - (terephthaloxy) bisphthalic anhydride and 1,2,4, 5-benzenetetracarboxylic dianhydride (PMDA). These may be used alone or in combination of 2 or more.
From the viewpoint of appearance quality, elastic modulus, total light transmittance, surface hardness, and bending resistance of the optical film, 3 ', 4,4 ' -biphenyltetracarboxylic dianhydride (BPDA) is preferably used as the tetracarboxylic compound that can be used for producing the resin, and 3,3 ', 4,4 ' -biphenyltetracarboxylic dianhydride (BPDA) and 4,4 ' - (hexafluoroisopropylidene) diphthalic anhydride (6FDA) are also preferably used.
Examples of the dicarboxylic acid compound that can be used for producing the polyamideimide resin include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and the like, acid chloride compounds and acid anhydrides thereof. 1 kind of dicarboxylic acid compound may be used, or 2 or more kinds may be used in combination.
Examples of the dicarboxylic acid compound that can be used for producing the polyamideimide resin and that provides the structural unit (b1) wherein Z in the formula (b) is represented by the formula (1) include ring-assembled aromatic dicarboxylic acid compounds. Examples of the dicarboxylic acid compound that can be used for producing the resin include the compound represented by the above formula (12) (dicarboxylic acid chloride), for example, 3 ', 4, 4' -biphenyldicarboxylic acid chloride (BPDC).
As the dicarboxylic acid compound, terephthalic acid, isophthalic acid, 4' -oxybis benzoic acid or an acid chloride compound thereof can be preferably used. In addition to terephthalic acid, 4' -oxybis-benzoic acid or their acid chloride compounds, other dicarboxylic acid compounds may also be used. Examples of the other dicarboxylic acid compounds include isophthalic acid; naphthalenedicarboxylic acid; 4, 4' -biphenyldicarboxylic acid; 3, 3' -biphenyldicarboxylic acid; a dicarboxylic acid compound of chain hydrocarbon having 8 or less carbon atoms and 2 benzoic acids via a single bond, -CH2-、-C(CH3)2-、-C(CF3)2-、-SO2Examples of the compound in which-or phenylene groups are bonded to each other and the acid chloride compound thereof are mentioned. Specifically, 4 '-oxybis (benzoyl chloride) and terephthaloyl chloride are preferable, and 4, 4' -oxybis (benzoyl chloride) and terephthaloyl chloride are more preferably used in combination.
Examples of the diamine compound that can be used for producing the polyamideimide resin include aromatic diamines. In the present embodiment, the "aromatic diamine" refers to a diamine in which an amino group is directly bonded to an aromatic ring, and may contain an aliphatic group or other substituent in a part of the structure. The aromatic ring may be a monocyclic ring or a condensed ring, and examples thereof include a benzene ring, a naphthalene ring, an anthracene ring, and a fluorene ring, but are not limited thereto. Among these, benzene rings are preferred.
Examples of the aromatic diamine include aromatic diamines having 1 aromatic ring such as p-phenylenediamine, m-phenylenediamine, 2, 4-tolylenediamine, m-xylylenediamine, p-xylylenediamine, 1, 5-diaminonaphthalene and 2, 6-diaminonaphthalene, 4 ' -diaminodiphenylmethane, 4 ' -diaminodiphenylpropane, 4 ' -diaminodiphenyl ether, 3 ' -diaminodiphenyl ether, 4 ' -diaminodiphenyl sulfone, 3 ' -diaminodiphenyl sulfone, 1, 4-bis (4-aminophenoxy) benzene, 1, 3-bis (4-aminophenoxy) benzene, bis [4- (4-aminophenoxy) phenyl ] sulfone, p-phenylenediamine, m-phenylenediamine, p-xylylenediamine, 1, 5-diaminonaphthalene, 2, 6-diaminonaphthalene, etc., 4 ' -diaminodiphenyl methane, 4 ' -diaminodiphenyl propane, 4 ' -diaminodiphenyl ether, 3,4 ' -diaminodiphenyl ether, 4-diaminodiphenyl sulfone, 3 ' -diaminodiphenyl sulfone, 1, 4-bis (4-aminophenoxy) benzene, 1, 3-bis (4-amino-phenoxy) benzene, bis (4-phenylene) sulfone, bis (4-phenylene) benzene, bis (4-phenylene) benzene, bis (bis) benzene) sulfone, bis (4-phenylene) benzene, bis (4-phenylene) benzene, bis (p) benzene, bis (4-phenylene) benzene, bis (p-phenylene) benzene, bis (2, bis (p-phenylene) benzene, 2, bis (p-phenylene) benzene, 2, bis (p-phenylene) benzene, bis (p-phenylene) benzene, 2, bis (bis) benzene, 2, bis (p) benzene, 2, bis (p-phenylene) benzene, Bis [4- (3-aminophenoxy) phenyl ] sulfone, 2-bis [4- (4-aminophenoxy) phenyl ] propane, 2-bis [4- (3-aminophenoxy) phenyl ] propane, 2' -dimethylbenzidine, 2' -bis (trifluoromethyl) -4,4 ' -diaminobiphenyl (sometimes referred to as TFMB), aromatic diamines having 2 or more aromatic rings, such as 4, 4' -bis (4-aminophenoxy) biphenyl, 9-bis (4-aminophenyl) fluorene, 9-bis (4-amino-3-methylphenyl) fluorene, 9-bis (4-amino-3-chlorophenyl) fluorene, and 9, 9-bis (4-amino-3-fluorophenyl) fluorene. These may be used alone or in combination of 2 or more.
The aromatic diamine is preferably 4,4 ' -diaminodiphenylmethane, 4 ' -diaminodiphenylpropane, 4 ' -diaminodiphenylether, 3 ' -diaminodiphenylether, 4 ' -diaminodiphenylsulfone, 3 ' -diaminodiphenylsulfone, 1, 4-bis (4-aminophenoxy) benzene, bis [4- (4-aminophenoxy) phenyl ] sulfone, bis [4- (3-aminophenoxy) phenyl ] sulfone, 2-bis [4- (4-aminophenoxy) phenyl ] propane, 2-bis [4- (3-aminophenoxy) phenyl ] propane, 2' -dimethylbenzidine, 2' -bis (trifluoromethyl) -4,4 ' -diaminobiphenyl (TFMB), 4,4 '-bis (4-aminophenoxy) biphenyl, 4' - (hexafluoropropylidene) diphenylamine (6FDAM), more preferably 4,4 '-diaminodiphenylmethane, 4' -diaminodiphenylpropane, 4 '-diaminodiphenyl ether, 4' -diaminodiphenylsulfone, 1, 4-bis (4-aminophenoxy) benzene, bis [4- (4-aminophenoxy) phenyl ] sulfone, 2-bis [4- (4-aminophenoxy) phenyl ] propane, 2' -dimethylbenzidine, 2' -bis (trifluoromethyl) -4,4 ' -diaminobiphenyl (TFMB), 4 ' -bis (4-aminophenoxy) biphenyl, 4 ' - (hexafluoropropylidene) diphenylamine (6 FDAM). These may be used alone or in combination of 2 or more.
As the diamine compound that can be used for producing the polyamideimide resin, an aliphatic diamine may be further used in addition to the aromatic diamine. The "aliphatic diamine" refers to a diamine in which an amino group is directly bonded to an aliphatic group, and may contain an aromatic ring or other substituent in a part of the structure. Examples of the aliphatic diamine include acyclic aliphatic diamines such as 1, 6-hexamethylenediamine, and cyclic aliphatic diamines such as 1, 3-bis (aminomethyl) cyclohexane, 1, 4-bis (aminomethyl) cyclohexane, norbornanediamine, and 4, 4' -diaminodicyclohexylmethane.
Among the diamine compounds, from the viewpoint of easily improving the appearance quality, surface hardness, total light transmittance, elastic modulus, flexibility, bending resistance, and easily obtaining low coloring property of the optical film, it is preferable to use 1 or more selected from the group consisting of aromatic diamines having a biphenyl structure. More preferably, 1 or more selected from the group consisting of 2,2 '-dimethylbenzidine, 2' -bis (trifluoromethyl) benzidine, 4 '-bis (4-aminophenoxy) biphenyl, 4' -diaminodiphenyl ether, and 4,4 '- (hexafluoropropylidene) diphenylamine is used, and still more preferably, 1 or more selected from the group consisting of 2,2' -bis (trifluoromethyl) -4,4 '-diaminobiphenyl (TFMB) and 4, 4' - (hexafluoropropylidene) diphenylamine (6FDAM) is used.
The polyamideimide resin may be a product obtained by further reacting tetracarboxylic acid, tricarboxylic acid, and their anhydrides and derivatives in addition to the tetracarboxylic acid compound, within a range that does not impair various physical properties of the optical laminate.
Examples of the other tetracarboxylic acid include water adducts of anhydrides of the above tetracarboxylic acid compounds.
Examples of the tricarboxylic acid compound include an aromatic tricarboxylic acid, an aliphatic tricarboxylic acid, and a similar acid chloride compound or acid anhydride thereof, and 2 or more kinds thereof may be used in combination. Specific examples thereof include 1,3, 5-benzenetricarboxylic acid or an acid chloride compound thereof, and anhydrides of 1,2, 4-benzenetricarboxylic acid; 2,3, 6-naphthalene tricarboxylic acid-2, 3-anhydride; phthalic anhydride and benzoic acid through single bond, -O-, -CH2-、-C(CH3)2-、-C(CF3)2-、-SO2-or phenylene groups.
In the production of the resin, the amount of each of the diamine compound, the tetracarboxylic acid compound and the dicarboxylic acid compound to be used may be appropriately selected depending on the ratio of each structural unit of the desired polyamideimide resin.
The method for producing the polyamideimide resin is not particularly limited as long as the polyamideimide resin described above can be obtained, and it is preferable to produce the polyamideimide resin by a production method in which a dicarboxylic acid compound is added in portions and a diamine compound, a tetracarboxylic acid compound and a dicarboxylic acid compound are reacted, from the viewpoint of easily improving the appearance quality, elastic modulus and total light transmittance of the optical film; more preferably, the polyamideimide resin is produced by a method comprising the step (I) of reacting a diamine compound with a tetracarboxylic acid compound to produce an intermediate (a), and the step (II) of reacting the intermediate (a) with a dicarboxylic acid compound, wherein the dicarboxylic acid compound is added in portions in the step (II).
Therefore, the polyamideimide resin is preferably a resin produced by a production method in which a dicarboxylic acid compound is added in portions and a diamine compound, a tetracarboxylic acid compound and a dicarboxylic acid compound are reacted, and more preferably a resin produced by a production method in which a dicarboxylic acid compound is added in portions in the step (II) and which comprises the step (I) of reacting a diamine compound and a tetracarboxylic acid compound to produce an intermediate (a) and the step (II) of reacting the intermediate (a) and a dicarboxylic acid compound.
When the polyamideimide resin is produced by the production method including the above-mentioned step (I) and step (II), the reaction temperature of the step (I) of reacting the diamine compound with the tetracarboxylic acid compound to produce the intermediate (a) is not particularly limited, and may be, for example, 5 to 200 ℃, preferably 5 to 100 ℃, more preferably 5 to 50 ℃, and further preferably 5 to room temperature (about 25 ℃). The reaction time may be, for example, 1 minute to 72 hours, preferably 10 minutes to 24 hours. The reaction may be carried out in air or an inert gas atmosphere such as nitrogen or argon while stirring, or may be carried out under normal pressure, increased pressure or reduced pressure. In a preferred embodiment, the stirring is carried out under normal pressure and/or under the inert gas atmosphere.
In the step (I), the diamine compound reacts with the tetracarboxylic acid compound to produce the intermediate (a), i.e., polyamic acid. Therefore, the intermediate (a) has at least a structural unit derived from a diamine compound and a structural unit derived from a tetracarboxylic acid compound.
Next, in the step (II), the intermediate (a) is reacted with a dicarboxylic acid compound, and here, the dicarboxylic acid compound is preferably added in portions. The intermediate (a) is reacted with a dicarboxylic acid compound by adding the dicarboxylic acid compound to the reaction solution obtained in the step (I) in portions. The molecular weight of the polyamideimide resin can be easily adjusted to the above-mentioned preferable range by adding the dicarboxylic acid compound in portions rather than at once. In the present specification, the batch addition means: the dicarboxylic acid compound to be added is added in several portions, and more specifically, the dicarboxylic acid to be added is divided into specific amounts and added separately at predetermined intervals or for predetermined time. The prescribed interval or prescribed time also includes a very short interval or time, and therefore the batch addition also includes continuous addition or continuous feeding.
In the step (II), the number of times of addition of the dicarboxylic acid compound in portions may be appropriately selected depending on the scale of the reaction, the kind of the raw material, and the like, and is preferably 2 to 20 times, more preferably 3 to 10 times, and still more preferably 3 to 6 times. When the number of batches is within the above range, it is considered that the transmittance of the optical film is easily maintained and the structure optimal for increasing the elastic modulus is formed. It is also considered that the weight average molecular weight of the polyamideimide resin can be easily adjusted to the above-mentioned preferred range.
The dicarboxylic acid compound may be added in an equal amount or in an unequal amount. The time between each addition (hereinafter, sometimes referred to as an addition interval) may be the same or different. In addition, in the case of adding two or more dicarboxylic acid compounds, the term "adding in portions" means adding all the dicarboxylic acid compounds in portions, and the method of adding the dicarboxylic acid compounds in portions is not particularly limited, and for example, the dicarboxylic acid compounds may be added together or in portions, or the dicarboxylic acid compounds may be added in portions, or a combination thereof.
In the step (II), the dicarboxylic acid compound is preferably added in an amount of 1 to 40 mol%, more preferably 2 to 25 mol%, based on the total molar amount of the dicarboxylic acid compound to be added, when the weight average molecular weight of the polyamide resin is preferably 10% or more, more preferably 15% or more, based on the weight average molecular weight of the polyamide resin to be obtained.
The reaction temperature in the step (II) is not particularly limited, and may be, for example, 5 to 200 ℃, preferably 5 to 100 ℃, more preferably 5 to 50 ℃, and still more preferably 5 to room temperature (about 25 ℃). The reaction may be carried out in air or an inert gas atmosphere such as nitrogen or argon while stirring, or may be carried out under normal pressure, increased pressure or reduced pressure. In a preferred embodiment, the step (II) is performed under normal pressure and/or under the inert gas atmosphere while stirring.
In the step (II), the dicarboxylic acid compound is added in portions, and then the mixture is reacted by stirring for a predetermined time, whereby a polyamideimide precursor can be obtained. The polyamideimide precursor may be isolated, for example, by: the polyamideimide precursor is precipitated by adding a large amount of water or the like to a reaction solution containing the polyamideimide precursor, followed by filtration, concentration, drying, and the like.
In the step (II), the intermediate (a) is reacted with a dicarboxylic acid compound to obtain a polyamideimide precursor. Accordingly, the polyamideimide precursor means a polyamideimide having at least a structural unit derived from a diamine compound, a structural unit derived from a tetracarboxylic acid, and a structural unit derived from a dicarboxylic acid compound before imidization (before ring closure).
In the production of the resin, the reaction temperature of the diamine compound, the tetracarboxylic acid compound and the dicarboxylic acid compound is not particularly limited, and is, for example, 5 to 350 ℃, preferably 5 to 200 ℃, and more preferably 5 to 100 ℃. The reaction time is also not particularly limited, and is, for example, about 30 minutes to 10 hours. If necessary, the reaction may be carried out in an inert atmosphere or under reduced pressure. In a preferred embodiment, the reaction is carried out under normal pressure and/or in an inert gas atmosphere while stirring. In addition, the reaction is preferably carried out in a solvent which is inactive to the reaction. The solvent is not particularly limited as long as it does not affect the reaction, and examples thereof include alcohol solvents such as water, methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, 1-methoxy-2-propanol, 2-butoxyethanol, and propylene glycol monomethyl ether; ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ -butyrolactone, γ -valerolactone, propylene glycol methyl ether acetate, and ethyl lactate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, and methyl isobutyl ketone; aliphatic hydrocarbon solvents such as pentane, hexane, and heptane; alicyclic hydrocarbon solvents such as ethylcyclohexane; aromatic hydrocarbon solvents such as toluene and xylene; nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran and dimethoxyethane; chlorine-containing solvents such as chloroform and chlorobenzene; amide solvents such as N, N-dimethylacetamide and N, N-dimethylformamide; sulfur-containing solvents such as dimethyl sulfone, dimethyl sulfoxide and sulfolane; carbonate solvents such as ethylene carbonate and propylene carbonate; and combinations thereof (mixed solvents). Among these, an amide solvent is preferably used from the viewpoint of solubility.
The method for producing a polyamideimide resin may further include the step (III) of imidizing the polyamideimide precursor in the presence of an imidization catalyst. By supplying the polyamideimide precursor obtained in the step (II) toIn the step (III), a structural unit having a polyamic acid structure in a structural unit of the polyamideimide precursor is partially imidized (ring-closed), and a polyamideimide resin including a structural unit represented by formula (1) and a structural unit represented by formula (2) can be obtained. Examples of the imidization catalyst include aliphatic amines such as tripropylamine, dibutylpropylamine, and ethyldibutylamine; n-ethylpiperidine, N-propylpiperidine, N-butylpyrrolidine, N-butylpiperidine, and N-propylhexahydroazepino
Figure BDA0003131483550000561
Alicyclic amines (monocyclic); azabicyclo [2.2.1]Heptane, azabicyclo [3.2.1]Octane, azabicyclo [2.2.2]Octane, and azabicyclo [3.2.2]Alicyclic amines (polycyclic) such as nonane; and aromatic amines such as pyridine, 2-methylpyridine (2-picoline), 3-methylpyridine (3-picoline), 4-methylpyridine (4-picoline), 2-ethylpyridine, 3-ethylpyridine, 4-ethylpyridine, 2, 4-dimethylpyridine, 2,4, 6-trimethylpyridine, 3, 4-cyclopentenopyridine, 5,6,7, 8-tetrahydroisoquinoline, and isoquinoline. In addition, from the viewpoint of facilitating the imidization reaction, it is preferable to use an acid anhydride together with an imidization catalyst. Examples of the acid anhydride include conventional acid anhydrides usable in the imidization reaction, and specific examples thereof include aliphatic acid anhydrides such as acetic anhydride, propionic anhydride, and butyric anhydride, and aromatic acid anhydrides such as phthalic acid.
The polyamide imide resin can be separated (separated and purified) by a conventional method, for example, a separation means such as filtration, concentration, extraction, crystallization, recrystallization, column chromatography, or a separation means combining these, and in a preferred embodiment, the separation can be carried out by: the polyamide imide resin is precipitated by adding a large amount of an alcohol such as methanol to a reaction solution containing the polyamide imide resin, followed by concentration, filtration, drying, and the like.
< Filler >
The optical film of the present invention may further contain at least 1 type of filler in addition to the polyamide-imide resin. Examples of the filler include organic particles and inorganic particles, and preferably inorganic particles. The inorganic particles include metal oxide particles such as silica, zirconia, alumina, titania, zinc oxide, germanium oxide, indium oxide, tin oxide, indium tin oxide, antimony oxide, and cerium oxide, and metal fluoride particles such as magnesium fluoride and sodium fluoride, and among these, silica particles, zirconia particles, and alumina particles are preferable from the viewpoint of easily improving the elastic modulus and/or tear strength of the optical film and easily improving the impact resistance, and silica particles are more preferable. These fillers may be used alone or in combination of 2 or more.
The average primary particle diameter of the filler and the silica particles is preferably 1nm or more, more preferably 5nm or more, further preferably 10nm or more, further more preferably 15nm or more, particularly preferably 20nm or more, preferably 100nm or less, more preferably 90nm or less, further preferably 80nm or less, further more preferably 70nm or less, particularly preferably 60nm or less, particularly preferably 50nm or less, and particularly preferably 40nm or less. When the average primary particle size of the silica particles is within the above range, aggregation of the silica particles is easily suppressed, and the optical properties of the obtained optical film are easily improved. The average primary particle diameter of the filler can be measured by the BET method. The average primary particle size may be measured by image analysis using a transmission electron microscope or a scanning electron microscope.
When the optical film of the present invention contains a filler, preferably silica particles, the content of the filler is usually 0.1 part by mass or more, preferably 1 part by mass or more, more preferably 5 parts by mass or more, further preferably 10 parts by mass or more, further preferably 20 parts by mass or more, particularly preferably 30 parts by mass or more, and preferably 60 parts by mass or less, per 100 parts by mass of the optical film. When the content of the filler is not less than the above lower limit, the elastic modulus of the optical film to be obtained is easily increased. When the content of the filler is not more than the upper limit, the optical properties of the optical film are easily improved.
< ultraviolet absorber >
The optical film of the present invention may comprise at least 1 ultraviolet absorber. The ultraviolet absorber can be appropriately selected from those generally used as ultraviolet absorbers in the field of resin materials. The ultraviolet absorber may contain a compound that absorbs light having a wavelength of 400nm or less. Examples of the ultraviolet absorber include at least 1 compound selected from the group consisting of benzophenone-based compounds, salicylate-based compounds, benzotriazole-based compounds, and triazine-based compounds. The ultraviolet absorber may be used alone or in combination of two or more. Since the optical film contains the ultraviolet absorber, deterioration of the resin can be suppressed, and thus, when the optical film of the present invention is applied to a display device or the like, visibility can be improved. In the present specification, the term "related compound" refers to a derivative of a compound to which the "related compound" is attached. For example, the "benzophenone-based compound" refers to a compound having benzophenone as a matrix skeleton and a substituent bonded to benzophenone.
When the optical film of the present invention contains an ultraviolet absorber, the content of the ultraviolet absorber is preferably 0.01 to 10 parts by mass, more preferably 1 to 8 parts by mass, and still more preferably 2 to 7 parts by mass, based on the mass of the polyamideimide resin contained in the optical film. When the content of the ultraviolet absorber is not less than the above lower limit, the ultraviolet absorbability is easily improved. When the content of the ultraviolet absorber is not more than the above upper limit, decomposition of the ultraviolet absorber by heat during production of the substrate can be suppressed, and optical characteristics, for example, haze can be easily improved.
< other additives >
The optical film of the present invention may further contain other additives besides the filler and the ultraviolet absorber. Examples of the other additives include colorants such as antioxidants, mold release agents, stabilizers, bluing agents, flame retardants, pH adjusters, silica dispersants, lubricants, thickeners, and leveling agents. When other additives are contained, the content thereof may be preferably 0.001 to 20 parts by mass, more preferably 0.01 to 15 parts by mass, and still more preferably 0.1 to 10 parts by mass, relative to the mass of the optical film.
(method for producing optical film)
The method for producing the optical film of the present invention is not particularly limited, and for example, a production method including the steps of:
(a) a varnish preparation step of preparing a polyamide imide resin varnish containing at least the polyamide imide resin and a solvent;
(b) a coating step of coating a varnish on a support material to form a coating film; and
(c) and an optical film forming step of drying the applied liquid (coating film) to form an optical film.
In the varnish preparation step, the polyamide imide resin is dissolved in a solvent, and if necessary, the above-mentioned additives such as the filler and the ultraviolet absorber are added and stirred and mixed to prepare a varnish. When silica particles are used as the filler, a silica sol obtained by replacing a dispersion of a silica sol containing silica particles with a solvent capable of dissolving the resin, for example, a solvent usable in the preparation of a varnish described below, may be added to the resin.
The solvent used in the preparation of the varnish is not particularly limited as long as the resin can be dissolved. Examples of the solvent include amide solvents such as N, N-dimethylacetamide and N, N-dimethylformamide; lactone solvents such as γ -butyrolactone (GBL) and γ -valerolactone; sulfur-containing solvents such as dimethyl sulfone, dimethyl sulfoxide and sulfolane; carbonate solvents such as ethylene carbonate and propylene carbonate; and combinations thereof (mixed solvents). Among these, amide solvents and lactone solvents are preferable, and lactone solvents are more preferable. When a lactone-based solvent is used, a film having high optical properties tends to be obtained. These solvents may be used alone or in combination of two or more. The varnish may contain water, an alcohol solvent, a ketone solvent, an acyclic ester solvent, an ether solvent, and the like. The solid content concentration in the polyamide imide resin varnish is preferably 1 to 25% by mass, more preferably 5 to 20% by mass, and still more preferably 5 to 15% by mass, from the viewpoint of easily improving the stability of the polyamide imide resin varnish. In addition, from the viewpoint of easily improving the stability of the polyamideimide resin varnish, the concentration of the solvent in the polyamideimide resin varnish of the present invention is preferably 75 to 99% by mass, more preferably 80 to 95% by mass, and even more preferably 85 to 95% by mass, based on the total amount of the polyamideimide resin varnish.
In the coating step, a varnish is applied to the support material by a known coating method to form a coating film. Examples of known coating methods include roll coating methods such as wire bar coating, reverse coating, and gravure coating, die coating, comma coating, lip coating, spin coating, screen coating, spray coating, dipping, spraying, and casting.
In the optical film forming step, the coating film is dried and peeled from the support material, whereby an optical film can be formed. After the peeling, a step of drying the optical film may be further provided. The drying of the coating film may be carried out at a temperature of 50 to 350 ℃. If necessary, the coating film may be dried in an inert atmosphere or under reduced pressure.
Examples of the support material include a metal-based SUS plate, and a resin-based PET film, a PEN film, a polyamide-based resin film, a polyimide-based resin film, a cycloolefin-based polymer (COP) film, and an acrylic film. Among them, a PET film, a COP film, and the like are preferable from the viewpoint of excellent smoothness and heat resistance, and a PET film is more preferable from the viewpoint of adhesion to an optical film and cost.
The application of the optical film of the present invention is not particularly limited, and the optical film can be used for various applications. As described above, the optical film of the present invention may be a single layer or a laminate, and the optical film of the present invention may be used as it is, or may be used in the form of a laminate with another film. When the optical film is a laminate, the optical film is referred to as an optical film including all layers laminated on one or both surfaces of the optical film.
(functional layer)
At least one surface of the optical film of the present invention may have 1 or more functional layers stacked thereon. Examples of the functional layer include an ultraviolet absorbing layer, a hard coat layer, a primer layer, a gas barrier layer, an adhesive layer, a hue adjusting layer, and a refractive index adjusting layer. The functional layers may be used alone or in combination of two or more.
The ultraviolet absorbing layer is a layer having an ultraviolet absorbing function, and is composed of a main material selected from an ultraviolet curable transparent resin, an electron beam curable transparent resin, and a thermosetting transparent resin, and an ultraviolet absorber dispersed in the main material.
A hard coat layer may be provided on at least one side of the optical film of the present invention. The thickness of the hard coat layer is not particularly limited, and may be, for example, 2 to 100 μm. When the thickness of the hard coat layer is within the above range, sufficient scratch resistance can be secured, and the flex resistance is less likely to be lowered, and the problem of curling due to curing shrinkage is less likely to occur.
The aforementioned hard coat layer may be formed by: curing the hard coating composition including the reactive material capable of forming a cross-linked structure by irradiating active energy rays or imparting thermal energy; preferably by irradiation with active energy rays. The active energy ray is defined as an energy ray that can decompose a compound that generates an active species to generate an active species, and examples thereof include visible light, ultraviolet light, infrared light, X-ray, α -ray, β -ray, γ -ray, and electron beam, and preferable examples thereof include ultraviolet light. The hard coat composition contains at least 1 polymer selected from the group consisting of a radically polymerizable compound and a cationically polymerizable compound.
The radical polymerizable compound is a compound having a radical polymerizable group. The radical polymerizable group of the radical polymerizable compound may be a functional group capable of undergoing a radical polymerization reaction, and examples thereof include a group containing a carbon-carbon unsaturated double bond, specifically, a vinyl group and a (meth) acryloyl group. When the radical polymerizable compound has 2 or more radical polymerizable groups, the radical polymerizable groups may be the same or different. The number of radical polymerizable groups in 1 molecule of the radical polymerizable compound is preferably 2 or more in terms of increasing the hardness of the hard coat layer. The radical polymerizable compound preferably includes a compound having a (meth) acryloyl group in view of high reactivity, specifically, a compound called a polyfunctional acrylate monomer having 2 to 6 (meth) acryloyl groups in 1 molecule, an oligomer called epoxy (meth) acrylate, urethane (meth) acrylate, and polyester (meth) acrylate having several (meth) acryloyl groups in a molecule and having a molecular weight of several hundred to several thousand, and preferably 1 or more selected from the group consisting of epoxy (meth) acrylate, urethane (meth) acrylate, and polyester (meth) acrylate.
The cationically polymerizable compound is a compound having a cationically polymerizable group such as an epoxy group, an oxetane group, or a vinyl ether group. The number of the cationically polymerizable groups contained in 1 molecule of the cationically polymerizable compound is preferably 2 or more, and more preferably 3 or more, from the viewpoint of improving the hardness of the hard coat layer.
Among the above cationically polymerizable compounds, preferred are compounds having at least 1 of an epoxy group and an oxetanyl group as a cationically polymerizable group. A cyclic ether group such as an epoxy group or an oxetane group is preferable in that shrinkage accompanying the polymerization reaction is small. In addition, the compound having an epoxy group in a cyclic ether group has the following advantages: it is easy to obtain compounds having various structures, to exert no adverse effect on the durability of the obtained hard coat layer, and to control the compatibility with the radical polymerizable compound. In addition, the oxetanyl group in the cyclic ether group has the following advantages as compared with the epoxy group: the polymerization degree is easily increased, the forming speed of the network obtained by the cationic polymerizable compound of the obtained hard coat layer is increased, and even in the area mixed with the radical polymerizable compound, the unreacted monomer is not remained in the film, and the independent network is formed; and so on.
Examples of the cationically polymerizable compound having an epoxy group include: polyglycidyl ethers of polyhydric alcohols having an alicyclic ring or alicyclic epoxy resins obtained by epoxidizing compounds containing a cyclohexene ring or cyclopentene ring with an appropriate oxidizing agent such as hydrogen peroxide or a peroxy acid; aliphatic epoxy resins such as polyglycidyl ethers of aliphatic polyols or alkylene oxide adducts thereof, polyglycidyl esters of aliphatic long-chain polybasic acids, homopolymers and copolymers of glycidyl (meth) acrylate; glycidyl ethers produced by the reaction of bisphenols such as bisphenol a, bisphenol F and hydrogenated bisphenol a, or their derivatives such as alkylene oxide adducts and caprolactone adducts with epichlorohydrin, and glycidyl ether type epoxy resins derived from bisphenols such as Novolac epoxy resins.
The aforementioned hard coating composition may further comprise a polymerization initiator. Examples of the polymerization initiator include a radical polymerization initiator, a cationic polymerization initiator, a radical and cationic polymerization initiator, and they can be appropriately selected and used. These polymerization initiators are decomposed by at least one of irradiation with active energy rays and heating to generate radicals or cations, and radical polymerization and cationic polymerization are performed.
The radical polymerization initiator may be a substance that can release and initiate radical polymerization by at least one of irradiation with active energy rays and heating. Examples of the thermal radical polymerization initiator include organic peroxides such as hydrogen peroxide and perbenzoic acid, and azo compounds such as azobisbutyronitrile.
The active energy ray radical polymerization initiator includes a Type1 radical polymerization initiator which generates radicals by decomposition of molecules and a Type2 radical polymerization initiator which generates radicals by hydrogen abstraction reaction in the coexistence of a tertiary amine, and they can be used alone or in combination.
The cationic polymerization initiator may be a substance which can release a substance for initiating cationic polymerization by at least one of irradiation with active energy rays and heating. As the cationic polymerization initiator, aromatic iodonium salts, aromatic sulfonium salts, cyclopentadienyl iron (II) complexes, and the like can be used. Depending on the difference in structure, they can initiate cationic polymerization by either or both of irradiation with active energy rays or heating.
The polymerization initiator may be preferably contained in an amount of 0.1 to 10% by mass based on 100% by mass of the entire hard coat composition. When the content of the polymerization initiator is within the above range, the curing can be sufficiently advanced, the mechanical properties and the adhesion of the finally obtained coating film can be in a good range, and poor adhesion, a crack phenomenon, and a curl phenomenon due to curing shrinkage tend to be less likely to occur.
The hard coating composition may further include one or more selected from the group consisting of a solvent and an additive. The solvent may be used in a range that does not impair the effects of the present invention, as long as it is a solvent that can dissolve or disperse the polymerizable compound and the polymerization initiator and is known as a solvent for a hard coat composition in the art. The aforementioned additives may further include inorganic particles, leveling agents, stabilizers, surfactants, antistatic agents, lubricants, antifouling agents, and the like.
The pressure-sensitive adhesive layer is a layer having a pressure-sensitive adhesive function and has a function of bonding the optical film to another member. As a material for forming the adhesive layer, a generally known material can be used. For example, a thermosetting resin composition or a photocurable resin composition can be used. In this case, the resin composition can be cured by converting the polymer into a polymer by supplying energy after the curing.
The Pressure-Sensitive Adhesive layer may be a layer called a Pressure-Sensitive Adhesive (PSA) that is pressed and attached to an object. The pressure-sensitive adhesive may be a capsule adhesive as "a substance having adhesiveness at normal temperature and adhering to an adherend under light pressure" (JIS K6800) or as "an adhesive which contains a specific component in a protective film (microcapsule) and can maintain stability until the film is broken by an appropriate means (pressure, heat, or the like)".
The hue adjustment layer is a layer having a hue adjustment function and is a layer capable of adjusting a laminate including an optical film to a target hue. The hue adjustment layer is, for example, a layer containing a resin and a colorant. Examples of the colorant include inorganic pigments such as titanium oxide, zinc oxide, red iron oxide, titanium oxide-based calcined pigments, ultramarine blue, cobalt aluminate, and carbon black; organic pigments such as azo-based compounds, quinacridone-based compounds, anthraquinone-based compounds, perylene-based compounds, isoindolinone-based compounds, phthalocyanine-based compounds, quinophthalone-based compounds, threne-based compounds, and diketopyrrolopyrrole-based compounds; bulk pigments such as barium sulfate and calcium carbonate; and basic dyes, acid dyes, mordant dyes, and the like.
The refractive index adjustment layer is a layer having a function of adjusting the refractive index, and is, for example, a layer having a refractive index different from that of the optical film and capable of providing a predetermined refractive index to the optical laminate. The refractive index adjusting layer may be, for example, a resin layer containing an appropriately selected resin and, in some cases, a pigment, or may be a thin film of a metal. Examples of the pigment for adjusting the refractive index include silicon oxide, aluminum oxide, antimony oxide, tin oxide, titanium oxide, zirconium oxide, and tantalum oxide. The average primary particle diameter of the pigment may be 0.1 μm or less. By setting the average primary particle diameter of the pigment to 0.1 μm or less, diffuse reflection of light transmitted through the refractive index adjustment layer can be prevented, and deterioration in transparency can be prevented. Examples of the metal usable for the refractive index adjustment layer include metal oxides and metal nitrides such as titanium oxide, tantalum oxide, zirconium oxide, zinc oxide, tin oxide, silicon oxide, indium oxide, titanium oxynitride, titanium nitride, silicon oxynitride, and silicon nitride.
The optical film of the present invention may be a single layer or a laminate, and for example, the optical film produced as described above may be used as it is, or may be used in the form of a laminate with another film.
In one embodiment of the present invention, the optical film may have a protective film on at least one side (in other words, one side or both sides). For example, when one surface of the optical film has a functional layer, the protective film may be laminated on the surface of the optical film or the surface of the functional layer, or may be laminated on both the optical film and the functional layer. When the optical film has functional layers on both surfaces thereof, the protective film may be laminated on the surface on one functional layer side, or may be laminated on the surfaces on both functional layers. The protective film is not particularly limited as long as it is a peelable film that can temporarily protect the surface of the optical film or the functional layer. Examples of the protective film include polyester resin films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; the resin film is preferably selected from the group consisting of polyolefin resin films, polyethylene, polypropylene films and the like, acrylic resin films and the like. When the optical film has 2 protective films, the protective films may be the same or different.
The thickness of the protective film is not particularly limited, but is usually 10 to 120 μm, preferably 15 to 110 μm, and more preferably 20 to 100 μm. When the optical film has 2 protective films, the thicknesses of the respective protective films may be the same or different.
In a preferred embodiment of the present invention, the optical film of the present invention is useful as a front panel of a display device, particularly a front panel of a flexible display device (hereinafter, may be referred to as a window film). The flexible display device includes, for example, a flexible functional layer and an optical film laminated on the flexible functional layer and functioning as a front panel. That is, the front panel of the flexible display device is arranged on the viewing side on the flexible functional layer. The front panel has the function of protecting the flexible functional layer.
Examples of the display device include wearable devices such as televisions, smartphones, mobile phones, car navigation systems, tablet PCs, portable game machines, electronic paper, indicators, bulletin boards, clocks, and smartwatches. As the flexible display device, any display device having a flexible characteristic can be cited, and among them, a foldable display device and a rollable display device can be cited.
[ Flexible display device ]
The invention also provides a flexible display device provided with the optical film. The optical film of the present invention is preferably used as a front panel in a flexible display device, which is sometimes referred to as a window film. The flexible display device is formed of a laminate for flexible display device and an organic EL display panel, and the laminate for flexible display device is disposed on the viewing side of the organic EL display panel and is configured to be bendable. The laminate for a flexible display device may contain a window film, a polarizing plate (preferably a circularly polarizing plate), and a touch sensor, and the lamination order thereof is arbitrary, and it is preferable that the window film, the polarizing plate, and the touch sensor are laminated in this order or the window film, the touch sensor, and the polarizing plate are laminated in this order from the viewing side. The presence of the polarizing plate on the viewing side of the touch sensor is preferable because the pattern of the touch sensor is less likely to be observed and the visibility of the display image is good. The members may be laminated using an adhesive, a bonding agent, or the like. Further, the light-shielding film may include a light-shielding pattern formed on at least one surface of any one of the window film, the polarizing plate, and the touch sensor.
[ polarizing plate ]
The flexible display device of the present invention may further include a polarizing plate, preferably a circular polarizing plate. The circularly polarizing plate is a functional layer having a function of transmitting only a right-handed circularly polarized light component or a left-handed circularly polarized light component by laminating a λ/4 phase difference plate on a linearly polarizing plate. For example, can be used for: the external light is converted into right-handed circularly polarized light, the external light which is reflected by the organic EL panel and becomes left-handed circularly polarized light is blocked, only the light-emitting component of the organic EL is transmitted, and therefore the influence of reflected light is inhibited, and the image can be easily viewed. In order to achieve the circularly polarized light function, the absorption axis of the linear polarizer and the slow axis of the λ/4 phase difference plate need to be 45 ° in theory, but in practical applications, 45 ± 10 °. The linear polarizing plate and the λ/4 phase difference plate do not necessarily have to be stacked adjacent to each other, and the relationship between the absorption axis and the slow axis may satisfy the above range. It is preferable to achieve completely circularly polarized light at all wavelengths, but this is not necessarily the case in practical applications, and therefore, the circularly polarizing plate in the present invention also includes an elliptically polarizing plate. It is also preferable to further laminate a λ/4 retardation film on the viewing side of the linear polarizing plate to convert the emitted light into circularly polarized light, thereby improving visibility in a state where the polarized sunglasses are worn.
The linear polarizing plate is a functional layer having the following functions: light vibrating in the direction of the transmission axis is passed through, and polarized light of a vibration component perpendicular to the light is blocked. The linear polarizing plate may be a single linear polarizer or a structure including a linear polarizer and a protective film attached to at least one surface of the linear polarizer. The thickness of the linearly polarizing plate may be 200 μm or less, and preferably 0.5 to 100 μm. When the thickness is within the above range, the flexibility tends not to be lowered easily.
The linear polarizer may be a film-type polarizer manufactured by dyeing and stretching a polyvinyl alcohol (PVA) film. The polarizing performance can be exhibited by adsorbing a dichroic dye such as iodine to a PVA film that has been stretched to be oriented, or by stretching the PVA film in a state of being adsorbed to the dichroic dye to orient the dichroic dye. The film-type polarizer may be produced by steps such as swelling, crosslinking with boric acid, washing with an aqueous solution, and drying. The stretching and dyeing step may be performed as a PVA film alone or in a state of being laminated with another film such as polyethylene terephthalate. The thickness of the PVA film to be used is preferably 10 to 100 μm, and the stretch ratio is preferably 2 to 10 times.
In addition, as another example of the polarizer, a liquid crystal coating type polarizer formed by coating a liquid crystal polarizing composition may be used. The liquid crystal polarizing composition may include a liquid crystal compound and a dichroic dye compound. The liquid crystalline compound is preferably used because it has a property of exhibiting a liquid crystal state, and particularly, when it has a high-order alignment state such as smectic, it can exhibit high polarizing performance. The liquid crystalline compound preferably has a polymerizable functional group.
The dichroic dye may have liquid crystallinity or may have a polymerizable functional group, and may be aligned with the liquid crystal compound to exhibit dichroism. Any of the compounds in the liquid crystal polarizing composition has a polymerizable functional group.
The liquid crystal polarizing composition may further include an initiator, a solvent, a dispersant, a leveling agent, a stabilizer, a surfactant, a crosslinking agent, a silane coupling agent, and the like.
The liquid crystal polarizing layer is produced by applying a liquid crystal polarizing composition to an alignment film to form a liquid crystal polarizing layer.
The liquid crystal polarizing layer can be formed to a thinner thickness than the film type polarizer. The thickness of the liquid crystal polarizing layer may be preferably 0.5 to 10 μm, and more preferably 1 to 5 μm.
The foregoing alignment film can be produced, for example, by: the alignment film-forming composition is applied to a substrate, and alignment properties are imparted by rubbing, polarized light irradiation, or the like. The alignment film forming composition may contain a solvent, a crosslinking agent, an initiator, a dispersant, a leveling agent, a silane coupling agent, and the like in addition to the alignment agent. Examples of the orientation agent include polyvinyl alcohols, polyacrylates, polyamide acids, and polyimides. In the case of applying photo-alignment, an alignment agent containing a cinnamate group (cinnamate group) is preferably used. The weight average molecular weight of the polymer that can be used as the orientation agent may be about 10,000 to 1,000,000. The thickness of the alignment film is preferably 5 to 10,000nm, more preferably 10 to 500nm, from the viewpoint of alignment regulating force. The liquid crystal polarizing layer may be laminated by being peeled off from the substrate and then transferred, or the substrate may be directly laminated. The substrate preferably functions as a protective film, a retardation plate, or a transparent substrate for a window.
The protective film may be a transparent polymer film, and a material and an additive that can be used for the transparent base material may be used. Cellulose-based films, olefin-based films, acrylic films, and polyester films are preferable. The protective film may be a coating type protective film obtained by coating and curing a cationically curable composition such as an epoxy resin or a radically curable composition such as an acrylate. If necessary, a plasticizer, an ultraviolet absorber, an infrared absorber, a pigment, a colorant such as a dye, a fluorescent brightener, a dispersant, a heat stabilizer, a light stabilizer, an antistatic agent, an antioxidant, a lubricant, a solvent, or the like may be included. The thickness of the protective film may be 200 μm or less, preferably 1 to 100 μm. When the thickness of the protective film is within the above range, the flexibility of the protective film is not easily lowered. The protective film may also function as a transparent substrate for the window.
The λ/4 retardation plate is a film that imparts a retardation of λ/4 in a direction perpendicular to the traveling direction of incident light (i.e., in-plane direction of the film). The λ/4 retardation plate may be a stretched retardation plate produced by stretching a polymer film such as a cellulose film, an olefin film, or a polycarbonate film. If necessary, a phase difference adjusting agent, a plasticizer, an ultraviolet absorber, an infrared absorber, a pigment, a colorant such as a dye, a fluorescent brightener, a dispersant, a heat stabilizer, a light stabilizer, an antistatic agent, an antioxidant, a lubricant, a solvent, and the like may be included. The thickness of the stretched retardation film may be 200 μm or less, preferably 1 to 100 μm. When the thickness is within the above range, the flexibility of the film tends not to be easily lowered.
Further, another example of the λ/4 retardation plate may be a liquid crystal coating type retardation plate formed by coating a liquid crystal composition. The liquid crystal composition contains a liquid crystalline compound having a property of exhibiting a liquid crystal state such as a nematic state, a cholesteric state, or a smectic state. Any compound including a liquid crystalline compound in the liquid crystal composition has a polymerizable functional group. The liquid crystal coating type retardation plate may further contain an initiator, a solvent, a dispersant, a leveling agent, a stabilizer, a surfactant, a crosslinking agent, a silane coupling agent, and the like. The liquid crystal coated retardation plate can be produced by coating a liquid crystal composition on an alignment film and curing the coating to form a liquid crystal retardation layer, as described in the liquid crystal polarizing layer. The liquid crystal coating type retardation plate can be formed to a smaller thickness than the stretching type retardation plate. The thickness of the liquid crystal polarizing layer may be usually 0.5 to 10 μm, preferably 1 to 5 μm. The liquid crystal coated retardation film may be laminated by being peeled from a substrate and then transferred, or the substrate may be directly laminated. The substrate preferably functions as a protective film, a retardation plate, or a transparent substrate for a window.
In general, the birefringence is large as the wavelength is shorter, and the birefringence is small as the wavelength is longer. In this case, since it is not possible to achieve a retardation of λ/4 in all visible light regions, it is often designed so that an in-plane retardation of λ/4 is 100 to 180nm, preferably 130 to 150nm, in the vicinity of 560nm, which is high in visibility. The use of an inverse dispersion λ/4 phase difference plate using a material having a birefringence wavelength dispersion characteristic opposite to that of the usual one is preferable because it can improve visibility. As such a material, the material described in japanese patent application laid-open No. 2007-232873 and the like is preferably used also in the case of a stretched phase difference plate, and the material described in japanese patent application laid-open No. 2010-30979 is preferably used also in the case of a liquid crystal coated phase difference plate.
As another method, a technique of obtaining a wide-band λ/4 phase difference plate by combining with a λ/2 phase difference plate is also known (japanese patent application laid-open No. h 10-90521). The λ/2 phase difference plate can be manufactured by the same material method as the λ/4 phase difference plate. The combination of the stretching type retardation plate and the liquid crystal coating type retardation plate is arbitrary, and the use of the liquid crystal coating type retardation plate is preferable because the thickness can be reduced.
For the circularly polarizing plate, a method of laminating a positive C plate is also known in order to improve visibility in an oblique direction (japanese patent application laid-open No. 2014-224837). The positive C plate may be a liquid crystal coated retardation plate or a stretched retardation plate. The phase difference in the thickness direction is usually from-200 to-20 nm, preferably from-140 to-40 nm.
[ touch sensor ]
The flexible display device of the present invention may further include a touch sensor. The touch sensor may be used as an input mechanism. As the touch sensor, various types such as a resistive film type, a surface acoustic wave type, an infrared ray type, an electromagnetic induction type, and a capacitance type have been proposed, and any type may be used. Among them, the electrostatic capacitance system is preferable. The capacitive touch sensor may be divided into an active region and an inactive region located at a peripheral portion of the active region. The active region is a region corresponding to a display portion on the display panel on which a screen is displayed, and is a region in which a user's touch is sensed, and the inactive region is a region corresponding to a non-display portion on the display device on which a screen is not displayed. The touch sensor may include: a substrate having flexible properties; a sensing pattern formed on the active region of the substrate; and each sensing line formed in the inactive region of the substrate and used for connecting the sensing pattern with an external driving circuit through a pad (pad) portion. As the substrate having the flexible property, the same material as the transparent substrate of the window can be used. The substrate of the touch sensor preferably has a toughness of 2,000 MPa% or more in terms of suppressing cracks in the touch sensor. The toughness may be more preferably 2,000 to 30,000 MPa%. Here, the toughness is defined as the area of the lower part of a Stress (MPa) -strain (%) curve (Stress-strain curve) obtained by a tensile test of a polymer material up to a failure point.
The sensing pattern may include a1 st pattern formed along a1 st direction and a2 nd pattern formed along a2 nd direction. The 1 st pattern and the 2 nd pattern are arranged in mutually different directions. The 1 st pattern and the 2 nd pattern are formed in the same layer, and in order to sense a touched position, the patterns must be electrically connected. The 1 st pattern is a form in which the unit patterns are connected to each other via a terminal, and the 2 nd pattern is a structure in which the unit patterns are separated from each other into islands, and therefore, in order to electrically connect the 2 nd pattern, a separate bridge electrode is required. The sensing pattern may use a known transparent electrode material. Examples thereof include Indium Tin Oxide (ITO), Indium Zinc Oxide (IZO), zinc oxide (ZnO), Indium Zinc Tin Oxide (IZTO), Indium Gallium Zinc Oxide (IGZO), Cadmium Tin Oxide (CTO), PEDOT (poly (3, 4-ethylenedioxythiophene)), Carbon Nanotube (CNT), graphene, and a metal wire, and these may be used alone or in combination of 2 or more. Preferably, ITO can be used. The metal usable for the wire is not particularly limited, and examples thereof include silver, gold, aluminum, copper, iron, nickel, titanium, selenium, chromium, and the like. These may be used alone or in combination of 2 or more.
The bridge electrode may be formed on the insulating layer with an insulating layer interposed therebetween, on the sensing pattern, the bridge electrode may be formed on the substrate, and the insulating layer and the sensing pattern may be formed thereon. The bridge electrode may be formed of the same material as the sensor pattern, or may be formed of a metal such as molybdenum, silver, aluminum, copper, palladium, gold, platinum, zinc, tin, titanium, or an alloy of 2 or more of these metals. The 1 st pattern and the 2 nd pattern must be electrically insulated, and thus, an insulating layer is formed between the sensing pattern and the bridge electrode. The insulating layer may be formed only between the tab of the 1 st pattern and the bridge electrode, or may be formed in a structure of a layer covering the sensing pattern. In the latter case, the 2 nd pattern may be connected to the bridge electrode through a contact hole formed in the insulating layer. In the touch sensor, as means for appropriately compensating for a difference in transmittance between a pattern region where a pattern is formed and a non-pattern region where no pattern is formed (specifically, a difference in transmittance due to a difference in refractive index in these regions), an optical adjustment layer may be further included between the substrate and the electrode, and the optical adjustment layer may include an inorganic insulating substance or an organic insulating substance. The optical adjustment layer can be formed by applying a photocurable composition containing a photocurable organic binder and a solvent onto a substrate. The aforementioned photocurable composition may further comprise inorganic particles. The refractive index of the optical adjustment layer can be increased by the inorganic particles.
The photocurable organic binder may include, for example, a copolymer of monomers such as an acrylate monomer, a styrene monomer, and a carboxylic acid monomer. The photocurable organic binder may be, for example, a copolymer containing mutually different repeating units such as an epoxy group-containing repeating unit, an acrylate repeating unit, and a carboxylic acid repeating unit.
The inorganic particles may include, for example, zirconium dioxide particles, titanium dioxide particles, aluminum oxide particles, and the like. The photocurable composition may further contain various additives such as a photopolymerization initiator, a polymerizable monomer, and a curing assistant.
[ adhesive layer ]
The layers forming the laminate for a flexible display device, such as a window, a polarizing plate, and a touch sensor, and the film members constituting the layers, such as a linear polarizing plate and a λ/4 retardation plate, may be bonded together with an adhesive. As the adhesive, a commonly used adhesive such as an aqueous adhesive, an organic solvent adhesive, a solventless adhesive, a solid adhesive, a solvent volatile adhesive, an aqueous solvent volatile adhesive, a moisture curable adhesive, a heat curable adhesive, an anaerobic curable adhesive, an active energy ray curable adhesive, a curing agent hybrid adhesive, a hot melt adhesive, a pressure sensitive adhesive, and a rewetting adhesive can be used. Among them, water-based solvent-volatile adhesives, active energy ray-curable adhesives, and adhesives are generally used. The thickness of the adhesive layer can be adjusted as appropriate according to the required adhesive strength, and is, for example, 0.01 to 500. mu.m, preferably 0.1 to 300. mu.m. The adhesive layer may be present in a plurality of layers in the laminate for a flexible display device, and the thickness of each layer and the type of the adhesive used may be the same or different.
As the aqueous solvent volatile adhesive, a polyvinyl alcohol polymer, a water-soluble polymer such as starch, or a water-dispersed polymer such as an ethylene-vinyl acetate emulsion or a styrene-butadiene emulsion can be used as a main polymer. In addition to water and the main agent polymer, a crosslinking agent, a silane compound, an ionic compound, a crosslinking catalyst, an antioxidant, a dye, a pigment, an inorganic filler, an organic solvent, and the like may be added. In the case of bonding with the aqueous solvent volatile adhesive, the aqueous solvent volatile adhesive may be injected between the layers to be bonded, and the layers to be bonded may be bonded and then dried to impart adhesiveness. The thickness of the adhesive layer when the aqueous solvent-based volatile adhesive is used may be 0.01 to 10 μm, preferably 0.1 to 1 μm. When the aqueous solvent-volatile adhesive is used for forming a plurality of layers, the thickness of each layer and the type of the adhesive may be the same or different.
The active energy ray-curable adhesive can be formed by curing an active energy ray-curable composition containing a reactive material capable of forming an adhesive layer by irradiation with an active energy ray. The active energy ray-curable composition may contain at least 1 polymer selected from the group consisting of radical polymerizable compounds and cationic polymerizable compounds, which are similar to the hard coat composition. The radical polymerizable compound may be the same type of radical polymerizable compound as used in the hard coat composition, as used in the hard coat composition. As the radical polymerizable compound that can be used in the adhesive layer, a compound having an acryloyl group is preferable. In order to reduce the viscosity of the adhesive composition, a monofunctional compound is preferably contained.
The cationic polymerizable compound may be the same kind of cationic polymerizable compound as used in the hard coat composition, similarly to the hard coat composition. The cationically polymerizable compound used in the active energy ray-curable composition is preferably an epoxy compound. To reduce the viscosity of the adhesive composition, it is also preferable to include a monofunctional compound as a reactive diluent.
In the active energy ray composition, a polymerization initiator may be further contained. The polymerization initiator may be selected from a radical polymerization initiator, a cationic polymerization initiator, a radical and cationic polymerization initiator, and the like. These polymerization initiators are those which can be decomposed by at least one of irradiation with active energy rays and heating to generate radicals or cations, thereby allowing radical polymerization and cationic polymerization to proceed. The initiator described in the description of the hard coating composition, which can initiate at least either of radical polymerization or cationic polymerization by irradiation with active energy rays, may be used.
The active energy ray-curable composition may further contain an ion scavenger, an antioxidant, a chain transfer agent, an adhesion-imparting agent, a thermoplastic resin, a filler, a flow viscosity modifier, a plasticizer, an antifoaming agent, an additive, and a solvent. When the bonding is performed by the active energy ray-curable adhesive, the bonding may be performed by: the active energy ray-curable composition is applied to one or both of the adhesive layers and then bonded thereto, and the adhesive layer or both of the adhesive layers is irradiated with active energy rays through the adhesive layer or both of the adhesive layers to be cured. The thickness of the adhesive layer when the active energy ray-curable adhesive is used may be 0.01 to 20 μm, preferably 0.1 to 10 μm. When the active energy ray-curable adhesive is used for forming a plurality of layers, the thickness of each layer and the type of the adhesive used may be the same or different.
The adhesive may be classified into an acrylic adhesive, a urethane adhesive, a rubber adhesive, a silicone adhesive, and the like according to the base polymer, and may be used. The binder may contain a crosslinking agent, a silane compound, an ionic compound, a crosslinking catalyst, an antioxidant, an adhesion promoter, a plasticizer, a dye, a pigment, an inorganic filler, and the like in addition to the main polymer. The adhesive layer and the adhesive layer can be formed by dissolving and dispersing the components constituting the adhesive in a solvent to obtain an adhesive composition, applying the adhesive composition to a substrate, and then drying the adhesive composition. The adhesive layer may be formed directly or by transferring an adhesive layer separately formed on the substrate. A release film is also preferably used to cover the pressure-sensitive adhesive surface before bonding. The thickness of the adhesive layer when the adhesive is used may be 1 to 500. mu.m, preferably 2 to 300. mu.m. When the above-mentioned adhesive is used for forming a plurality of layers, the thickness of each layer and the kind of the adhesive used may be the same or different.
[ light-shielding pattern ]
The light-shielding pattern may be applied as at least a portion of a bezel (bezel) or a housing of the flexible display device. The wiring disposed at the edge of the flexible display device is hidden by the light-shielding pattern and is not easily viewed, thereby improving visibility of an image. The light-shielding pattern may be in the form of a single layer or a plurality of layers. The color of the light-shielding pattern is not particularly limited, and may have various colors such as black, white, metallic color, and the like. The light-shielding pattern may be formed of a pigment for color, and a polymer such as an acrylic resin, an ester resin, an epoxy resin, polyurethane, or polysiloxane. They may be used alone or in the form of a mixture of 2 or more. The light-shielding pattern can be formed by various methods such as printing, photolithography, and inkjet. The thickness of the light-shielding pattern is usually 1 to 100 μm, preferably 2 to 50 μm. Further, it is preferable to provide a shape such as an inclination in the thickness direction of the light-shielding pattern.
Examples
The present invention will be described in further detail below with reference to examples. In the examples, "%" and "part(s)" refer to% by mass and part(s) by mass unless otherwise specified. First, the evaluation method will be explained.
< preparation of sample for solvent resistance evaluation >
A reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device and a nitrogen inlet tube was charged with 97.0 parts by mass of n-butyl acrylate, 1.0 part by mass of acrylic acid, 0.5 part by mass of 2-hydroxyethyl acrylate, 200 parts by mass of ethyl acetate and 0.08 part by mass of 2,2' -azobisisobutyronitrile, and the air in the reaction vessel was replaced with nitrogen. The reaction solution was heated to 60 ℃ under stirring in a nitrogen atmosphere, reacted for 6 hours, and then cooled to room temperature to synthesize an acrylate polymer. The weight average molecular weight of the acrylate polymer contained in the obtained solution was measured, and found to be 1,800,000.
100 parts by mass (solid content equivalent; the same applies hereinafter) of the acrylate polymer obtained in the above step, 0.30 parts by mass of trimethylolpropane-modified tolylene diisocyanate (product name "CORONATE (registered trademark) L", manufactured by Tosoh Corporation) as an isocyanate-based crosslinking agent, and 0.30 parts by mass of 3-glycidoxypropyltrimethoxysilane (product name "KBM 403", manufactured by shin-Etsu chemical industry Co., Ltd.) as a silane coupling agent were mixed, sufficiently stirred, and diluted with ethyl acetate, thereby obtaining a coating solution of the pressure-sensitive adhesive composition.
The coating solution was applied to the release-treated surface (release layer surface) of a separator (manufactured by LINTEC Corporation: SP-PLR382190) with a coater so that the dried thickness became 25 μm, and then dried at 100 ℃ for 1 minute, and another separator (manufactured by LINTEC Corporation: SP-PLR381031) was attached to the surface of the adhesive layer opposite to the surface to which the separator was attached, to obtain an adhesive layer with a separator on both surfaces.
From the pressure-sensitive adhesive layer of the separator with both sides obtained as described above, a pressure-sensitive adhesive layer was formed on the black acrylic resin plate by bonding only the pressure-sensitive adhesive layer to the black acrylic resin plate (acrylic board), and the polyamideimide resin films obtained in examples and comparative examples were bonded to the pressure-sensitive adhesive layer, to obtain a laminate (sample for solvent resistance evaluation) in which the black acrylic resin plate, the pressure-sensitive adhesive layer, and the optical film were sequentially laminated.
< solvent resistance test >
Ethanol was dropped on the surface of the sample for solvent resistance evaluation on the optical film side, and the sample was covered with a glass cover and left to stand for 40 minutes. Meanwhile, when evaporation and drying of ethanol were confirmed by observing the film from above the cover glass in order to maintain the film in contact with ethanol all the time, the cover glass was once removed, and after dropping ethanol again, the cover glass was covered again. Thereafter, the cover film was removed and left at room temperature for 1 hour or more to dry the film.
< measurement of optical Properties before and after solvent resistance test >
L in the reflectance measurement for the optical film before and after the solvent resistance test*、a*And b*The value was evaluated under the following conditions using a spectrophotometer (CM3700A) manufactured by KONICA MINOLTA (ltd.).
Light source: d light source
Incident light: irradiating at an angle of 2 DEG from the normal direction with respect to the optical film
Detection mode: reflective SCE
Target mask: LAV cover (measuring range: diameter 8mm)
(measurement of Total light transmittance)
The total light transmittance of the optical film was measured in accordance with JIS K7105: 1981, using a fully automated direct reading haze computer HGM-2DP manufactured by Suga Test Instruments Co., Ltd.
(measurement of haze)
Haze of the optical film was measured according to JIS K7105: 1981, using a fully automated direct reading haze computer HGM-2DP manufactured by Suga Test Instruments Co., Ltd.
(measurement of modulus of elasticity)
The optical films obtained in examples and comparative examples were cut into long strips of 10mm × 100mm using a dumbbell cutter, to obtain test samples. The elastic modulus of the test sample was measured by a stress-strain curve under the conditions of a distance between chucks of 50mm and a tensile rate of 10 mm/min using AUTOGRAPH AG-IS manufactured by Shimadzu corporation, and the elastic modulus (GPa) of the optical film was calculated from the slope at a stress of 5 to 20 MPa.
(measurement of thickness)
The thickness of the optical film obtained in examples and comparative examples was measured using an ABS number dial gauge ("ID-C112 BS", manufactured by Mitutoyo corporation).
< determination of weight average molecular weight >
Gel Permeation Chromatography (GPC) measurement
(1) Pretreatment method
DMF eluent (10mmol/L lithium bromide solution) was added to the sample so that the concentration became 2mg/mL, and the mixture was heated at 80 ℃ for 30 minutes with stirring, cooled, and then filtered through a 0.45 μm membrane filter to obtain a filtrate as a measurement solution.
(2) Measurement conditions
Column: TSKgel α -2500 (7)7.8mm diameter. times.300 mm). times.1, and α -M ((13)7.8mm diameter. times.300 mm). times.2, manufactured by Tosoh Corporation
Eluent: DMF (with addition of 10mmol/L lithium bromide)
Flow rate: 1.0 mL/min
A detector: RI detector
Column temperature: 40 deg.C
Sample introduction amount: 100 μ L
Molecular weight standard: standard polystyrene
< evaluation of appearance quality after solvent treatment >
And (3) dropwise adding ethanol to the optical film, covering a glass cover, and standing for 40 minutes. Meanwhile, when evaporation and drying of ethanol were confirmed by observing the film from above the cover glass in order to maintain the film in contact with ethanol all the time, the cover glass was once removed, and after dropping ethanol again, the cover glass was covered again. Thereafter, the cover film was removed and left at room temperature for 1 hour or more to dry the film. The obtained adhesive layer for an optical film was adhered to a black plate, and the surface of the optical film contacted with ethanol was observed under a fluorescent lamp while changing the viewing angle, and the appearance quality was evaluated according to the following criteria.
(evaluation of appearance quality)
Good: the surface of the optical film was observed to be uniformly black at all viewing angles other than the angle of reflection of the fluorescent lamp.
And (delta): in almost all viewing angles other than the angle of reflection of a fluorescent lamp, the surface of the optical film is observed to be black, but there are some angles in which a part of the surface is observed to be white.
X: in addition to the angle of reflection of a fluorescent lamp, there are many angles at which a part of the surface of the optical film appears white due to scattering of reflected light, or there are many angles at which the entire surface appears white.
< Synthesis example 1: production of Polyamide-imide resin (1)
2,2 '-bis (trifluoromethyl) benzidine (TFMB) and N, N-dimethylacetamide (DMAc) were charged into a separable flask equipped with a stirring blade under a nitrogen atmosphere so that the solid content of TFMB became 5.87 mass%, and 4, 4' - (hexafluoroisopropylidene) diphthalic anhydride (6FDA) was further added in an amount of 30.16 mol% relative to TFMB, and TFMB and 6FDA were dissolved in DMAc with stirring at room temperature.
Next, 4' -oxybis (benzoyl chloride) (OBBC) was added to the flask so that it became 10.05 mol% with respect to TFMB, and terephthaloyl chloride (TPC) was added so that it became 60.30 mol% with respect to TFMB, and the reaction was performed.
Next, 105.53 mol% of acetic anhydride with respect to TFMB was added to the flask, and after stirring for 15 minutes, 35.17 mol% of 4-methylpyridine with respect to TFMB was added, and the reaction vessel was heated to 70 ℃ and further stirred for 3 hours to obtain a reaction solution.
The obtained reaction solution was cooled to room temperature, put into a large amount of methanol in a linear form, and the precipitated precipitate was taken out, immersed in methanol for 6 hours, and then washed with methanol. Then, the precipitate was dried under reduced pressure at 78 ℃ to obtain a polyamideimide resin (1). The weight average molecular weight of the polyamideimide resin (1) was 336,000.
< Synthesis example 2: production of Polyamide-imide resin (2)
In a nitrogen atmosphere, TFMB and DMAc were charged into a separable flask equipped with a stirring blade so that the solid content of TFMB became 5.51 mass%, and 4, 4' - (hexafluoropropylidene) diphenylamine (6FDAM) in an amount of 11.11 mol% relative to TFMB was further added thereto, and TFMB and 6FDAM were dissolved in DMAc with stirring at room temperature. Next, 3 ', 4, 4' -biphenyltetracarboxylic dianhydride (BPDA) was added to the flask so that it became 44.63 mol% with respect to TFMB, and stirred at room temperature for 12 hours. Thereafter, after cooling to 10 ℃, TPC was added so as to be 30.13 mol% with respect to TFMB, and stirred for 10 minutes, and further TPC was added so as to be 30.13 mol% with respect to TFMB, and stirred for 20 minutes. Thereafter, DMAc was added in an amount equivalent to that of the DMAc added first, TPC was added so as to be 6.70 mol% with respect to TFMB, and the mixture was stirred for 2 hours. Subsequently, diisopropylethylamine and 4-methylpyridine, 67.04 mol% based on TFMB, and acetic anhydride, 312.80 mol% based on TFMB, were added to the flask, and the mixture was stirred for 30 minutes, then the internal temperature was raised to 70 ℃, and the mixture was further stirred for 3 hours to obtain a reaction solution.
The obtained reaction solution was cooled to room temperature, put into a large amount of methanol in a linear form, and the precipitated precipitate was taken out, immersed in methanol for 6 hours, and then washed with methanol. Then, the precipitate was dried under reduced pressure at 60 ℃ to obtain a polyamideimide resin (2). The weight average molecular weight of the polyamideimide resin (2) is 556,000.
< Synthesis example 3: production of Polyamide-imide resin (3)
In a nitrogen atmosphere, TFMB and DMAc were added to a separable flask equipped with a stirring blade so that the solid content of TFMB became 4.75 mass%, and further, 6FDAM was added in an amount of 25.02 mol% relative to TFMB, and TFMB and 6FDAM were dissolved in DMAc with stirring at room temperature. Next, BPDA was added to the flask so that it became 75.78 mol% with respect to TFMB, and the mixture was stirred at room temperature for 16 hours. Thereafter, after cooling to 10 ℃, TPC was added so as to be 22.70 mol% with respect to TFMB, and stirred for 10 minutes, and further TPC was added so as to be 22.70 mol% with respect to TFMB, and stirred for 20 minutes. Thereafter, DMAc was added in an amount equivalent to that of the DMAc added first, TPC was added so as to be 5.06 mol% with respect to TFMB, and the mixture was stirred for 2 hours. Subsequently, diisopropylethylamine and 4-methylpyridine in an amount of 50.51 mol% based on TFMB, and acetic anhydride in an amount of 530.39 mol% based on TFMB were added to the flask, and the mixture was stirred for 30 minutes, then the internal temperature was increased to 70 ℃, and the mixture was further stirred for 3 hours to obtain a reaction solution.
The obtained reaction solution was cooled to room temperature, put into a large amount of methanol in a linear form, and the precipitated precipitate was taken out, immersed in methanol for 6 hours, and then washed with methanol. Then, the precipitate was dried under reduced pressure at 60 ℃ to obtain a polyamideimide resin (3). The weight average molecular weight of the polyamideimide resin (3) is 461,000.
< Synthesis example 4: production of Polyamide-imide resin (4)
In a nitrogen atmosphere, TFMB and DMAc were added to a separable flask equipped with a stirring blade so that the solid content of TFMB became 5.56 mass%, and 6FDAM was further added in an amount of 11.19 mol% relative to TFMB, and TFMB and 6FDAM were dissolved in DMAc with stirring at room temperature. Next, BPDA was added to the flask so that it was 34.01 mol% with respect to TFMB, and the mixture was stirred at room temperature for 16 hours. After cooling to 10 ℃, TPC was added in an amount of 30.60 mol% based on TFMB and OBBC was added in an amount of 5.67 mol% based on TFMB, and the mixture was stirred for 10 minutes. TPC was further added so that the amount of TPC was 30.60 mol% based on TFMB, followed by addition of OBBC at 5.67 mol% based on TFMB, and the mixture was stirred for 20 minutes. Thereafter, DMAc was added in an amount equivalent to that of the DMAc added first, TPC was added so as to be 6.81 mol% with respect to TFMB, and the mixture was stirred for 2 hours. Subsequently, diisopropylethylamine and 4-methylpyridine in an amount of 79.35 mol% based on TFMB, and acetic anhydride in an amount of 238.14 mol% based on TFMB were added to the flask, and the mixture was stirred for 30 minutes, then the internal temperature was raised to 70 ℃, and the mixture was further stirred for 3 hours to obtain a reaction solution.
The obtained reaction solution was cooled to room temperature, put into a large amount of methanol in a linear form, and the precipitated precipitate was taken out, immersed in methanol for 6 hours, and then washed with methanol. Then, the precipitate was dried under reduced pressure at 60 ℃ to obtain a polyamideimide resin (4). The weight average molecular weight of the polyamideimide resin (4) is 360,000.
< comparative example 1 >
(production of optical film)
The polyamideimide resin (1) obtained in synthesis example 1 and DMAc were mixed in such an amount that the content ratio of the polyamideimide resin in the resin composition became 11.0 mass%. The obtained resin composition was applied to a smooth surface of a polyester substrate (manufactured by Toyobo Co., Ltd., trade name "A4100") using an applicator so that the thickness of the self-supporting film became 55 μm, dried at 50 ℃ for 30 minutes and then dried at 140 ℃ 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 ℃ for 40 minutes under the atmospheric air to obtain a polyamideimide resin film (1) having a thickness of 50 μm.
< example 1 >
The polyamideimide resin (2) obtained in synthesis example 2 and DMAc were mixed in such an amount that the content ratio of the polyamideimide resin in the resin composition became 6.5 mass%. A polyamideimide resin film (2) was obtained in the same manner as in comparative example 1.
< example 2 >
The polyamideimide resin (3) obtained in synthesis example 3 and DMAc were mixed in such an amount that the content ratio of the polyamideimide resin in the resin composition became 6.5 mass%. A polyamideimide resin film (3) was obtained in the same manner as in comparative example 1.
< example 3 >
The polyamideimide resin (4) obtained in synthesis example 3 and DMAc were mixed in such an amount that the content ratio of the polyamideimide resin in the resin composition became 8.5 mass%. A polyamideimide resin film (4) was obtained in the same manner as in comparative example 1.
The polyamideimide resin films (1) to (4) obtained as described above were evaluated for total light transmittance, haze, solvent resistance test and appearance quality. The obtained results are shown in table 1.
[ Table 1]
Figure BDA0003131483550000801

Claims (14)

1. An optical film comprising a polyamideimide resin having at least a structural unit represented by formula (a) derived from a tetracarboxylic acid compound, a structural unit represented by formula (b) derived from a dicarboxylic acid compound, and a structural unit represented by formula (c) derived from a diamine compound,
the polyamideimide resin comprises at least one structural unit selected from the group consisting of a structural unit (a1) wherein Y in formula (a) is represented by formula (1) as the structural unit derived from a tetracarboxylic acid compound, and a structural unit (b1) wherein Z in formula (b) is represented by formula (1) as the structural unit derived from a dicarboxylic acid compound,
the optical film is based on L in reflected light measurement*a*b*Lightness L of the chromaticity System1 *L-base of the optical film after 40 minutes of contact with ethanol in measurement of color difference of surface*a*b*Lightness L of the chromaticity System2 *Absolute value of difference Δ L*The content of the organic acid is below 0.5,
[ chemical formula 1]
Figure FDA0003131483540000011
In the formula (a), Y represents a 4-valent organic group, in the formula (b), Z represents a 2-valent organic group, and in the formula (c), X representsA 2-valent organic radical, RcIndependently of each other, represents a hydrogen atom or a chemical bond;
[ chemical formula 2]
Figure FDA0003131483540000012
In the formula (1), the reaction mixture is,
Raindependently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, RaThe hydrogen atoms contained in (a) may be substituted independently of each other by halogen atoms,
n represents an integer of 0 to 2,
denotes a chemical bond, R*Represents a chemical bond in the case where Y is represented by formula (1), and represents R in the case where Z is represented by formula (1)a。
2. The optical film of claim 1, wherein the L-basis in reflectance photometry*a*b*B of the optical film of the color system1 *B of the optical film after 40 minutes of contact with ethanol2 *Absolute value of the difference Δ b*Is 0.1 or less.
3. The optical film according to claim 1 or 2, wherein the thickness of the optical film is 25 μm or more and 100 μm or less.
4. The optical film according to any one of claims 1 to 3, wherein the haze of the optical film is 5% or less.
5. The optical film according to any one of claims 1 to 4, wherein the polyamideimide resin comprises a structural unit (b2) represented by formula (2) as a structural unit derived from a dicarboxylic acid compound, and comprises a structural unit (c1) represented by formula (3) as a structural unit derived from a diamine compound,
[ chemical formula 3]
Figure FDA0003131483540000021
In the formula (2), Z1Represents a 2-valent aromatic group which may have a substituent, the 2-valent aromatic group being a monocyclic aromatic ring or a fused polycyclic aromatic ring, and represents a chemical bond;
[ chemical formula 4]
Figure FDA0003131483540000022
In the formula (3), X1Represents an optionally substituted 2-valent aromatic group, RcIndependently of each other, represents a hydrogen atom or a chemical bond.
6. The optical film according to claim 5, wherein X in the formula (3)1Is represented by the formula (4),
[ chemical formula 5]
Figure FDA0003131483540000031
In the formula (4), RbIndependently represent an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, RbWherein the hydrogen atoms contained in (a) are independently substituted by halogen atoms, and r is independently an integer of 1 to 4.
7. The optical film according to any one of claims 1 to 6, wherein the polyamideimide resin further comprises at least one structural unit selected from the group consisting of a structural unit (b3) wherein Z in formula (b) is represented by formula (5) as a structural unit derived from a dicarboxylic acid compound, a structural unit (c2) wherein X in formula (c) is represented by formula (5) as a structural unit derived from a diamine compound, and a structural unit (a2) wherein Y in formula (a) is represented by formula (6) as a structural unit derived from a tetracarboxylic acid compound,
[ chemical formula 6]
Figure FDA0003131483540000032
In the formula (5), Ar1Independently of each other, a 2-valent aromatic group which may have a substituent,
v represents a single bond, -O-, diphenylmethylene, a linear, branched or alicyclic 2-valent hydrocarbon group having 1 to 12 carbon atoms, or-SO2-, -S-, -CO-or-N (R)12) -, wherein the hydrogen atoms contained in the hydrocarbon group independently of each other may be substituted by halogen atoms, R12Represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom,
m represents an integer of 1 to 3, wherein when m is 2 or 3, a plurality of V may be the same or different,
represents a chemical bond;
[ chemical formula 7]
Figure FDA0003131483540000041
In the formula (6), Ar2Independently of each other, a 3-valent aromatic group which may have a substituent,
s represents an integer of 0 to 2,
Ar1v and Ar for formula (5)1V and x are as defined, wherein when s is 2, there are a plurality of V and Ar1Each of which may be the same as or different from each other, wherein V in the formula (6) is not a single bond.
8. The optical film according to claim 7, wherein the formula (5) and the formula (6) are represented by formula (7),
[ chemical formula 8]
Figure FDA0003131483540000042
In the formula (7), R1Independently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, R1The hydrogen atoms contained in (a) may be substituted independently of each other by halogen atoms,
R*represents R1Or a chemical bond to the substrate,
the symbol represents a chemical bond,
v represents a single bond, -O-, diphenylmethylene, a linear, branched or alicyclic 2-valent hydrocarbon group having 1 to 12 carbon atoms, or-SO2-, -S-, -CO-or-N (R)12) -, wherein the hydrogen atoms contained in the hydrocarbon group independently of each other may be substituted by halogen atoms, R12Represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom, wherein, when formula (6) is represented by formula (7), V is not a single bond.
9. The optical film according to claim 8, wherein formula (7) is represented by formula (7 ') or formula (7'),
[ chemical formula 9]
Figure FDA0003131483540000051
In the formula (7'), R*Represents a hydrogen atom or a chemical bond;
[ chemical formula 10]
Figure FDA0003131483540000052
In formula (7 ″), denotes a bond.
10. The optical film according to any one of claims 1 to 9, wherein formula (1) is represented by formula (1'),
[ chemical formula 11]
Figure FDA0003131483540000053
In the formula (1'), R represents a bond*And represents a chemical bond in the case where Y is represented by formula (1), and represents a hydrogen atom in the case where Z is represented by formula (1).
11. An optical film according to any one of claims 1 to 10, which is a film for a front panel of a flexible display device.
12. A flexible display device comprising the optical film according to any one of claims 1 to 11.
13. The flexible display device of claim 12, further provided with a touch sensor.
14. The flexible display device according to claim 12 or 13, further comprising a polarizing plate.
CN201980085975.XA 2018-12-28 2019-12-24 Optical film and flexible display device Pending CN113227210A (en)

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