CN116891752A - Liquid crystal aligning agent, liquid crystal alignment film, method for producing liquid crystal alignment film, and liquid crystal element - Google Patents

Liquid crystal aligning agent, liquid crystal alignment film, method for producing liquid crystal alignment film, and liquid crystal element Download PDF

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Publication number
CN116891752A
CN116891752A CN202310297142.8A CN202310297142A CN116891752A CN 116891752 A CN116891752 A CN 116891752A CN 202310297142 A CN202310297142 A CN 202310297142A CN 116891752 A CN116891752 A CN 116891752A
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liquid crystal
formula
group
aligning agent
alignment film
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尾崎刚史
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Changsha Dao'anjie New Materials Co ltd
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JNC Corp
JNC Petrochemical Corp
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Publication of CN116891752A publication Critical patent/CN116891752A/en
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    • GPHYSICS
    • G02OPTICS
    • G02FOPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333Constructional arrangements; Manufacturing methods
    • G02F1/1337Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
    • G02F1/133711Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers by organic films, e.g. polymeric films
    • G02F1/133723Polyimide, polyamide-imide
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K19/00Liquid crystal materials
    • C09K19/52Liquid crystal materials characterised by components which are not liquid crystals, e.g. additives with special physical aspect: solvents, solid particles
    • C09K19/54Additives having no specific mesophase characterised by their chemical composition
    • C09K19/56Aligning agents

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  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Nonlinear Science (AREA)
  • General Physics & Mathematics (AREA)
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  • Spectroscopy & Molecular Physics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Macromolecular Compounds Obtained By Forming Nitrogen-Containing Linkages In General (AREA)
  • Liquid Crystal (AREA)

Abstract

Provided are a liquid crystal alignment film capable of forming a liquid crystal display element having good contrast even when exposure energy for photo-alignment treatment is small, and a liquid crystal alignment agent capable of forming such a liquid crystal alignment film. A liquid crystal aligning agent comprising a polyamic acid or a derivative thereof obtained by reacting a tetracarboxylic acid derivative with a diamine, wherein the tetracarboxylic acid derivative comprises a compound represented by the formula (I), and the diamine comprises a compound selected from the group consisting of a compound represented by the formula (I)(DI-13) and (DI-17-1). Groups of formulae (I) 1 and 1 'and groups of formulae 2 and 2' may be bonded to the same oxygen atom, respectively; rb1 to Rb4 are independently a hydrogen atom or a methyl group, and at least one is a methyl group. R of formula (DI-13) 23 Alkyl, etc., p and q are independently integers from 0 to 4; k of formula (DI-17-1) is an integer of 1 to 6.

Description

Liquid crystal aligning agent, liquid crystal alignment film, method for producing liquid crystal alignment film, and liquid crystal element
Technical Field
The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal element using the liquid crystal alignment film. More specifically, the present invention relates to a liquid crystal alignment agent for photo-alignment (hereinafter, abbreviated as a liquid crystal alignment agent) for forming a liquid crystal alignment film for photo-alignment (hereinafter, abbreviated as a photo-alignment film) and a liquid crystal display element (hereinafter, abbreviated as a liquid crystal element) having the liquid crystal alignment film.
Background
The following liquid crystal elements are known: by controlling or modulating the alignment state of the liquid crystal layer in the element, the electromagnetic wave incident into the element can be subjected to optical phenomena such as refraction, scattering, reflection, and the like. Specifically, a liquid crystal antenna, a dimming window, an optical compensation material, and a variable phase shifter are known in addition to the following liquid crystal display element.
As liquid crystal display elements, liquid crystal display elements of various driving systems such as Twisted Nematic (TN) mode, super Twisted Nematic (Super Twisted Nematic, STN) mode, in-Plane Switching (IPS) mode, fringe field Switching (Fringe Field Switching, FFS) mode, and vertical alignment (Vertical Alignment, VA) mode (Multi-domain vertical alignment (Multi-domain Vertical Alignment)) are known. These liquid crystal display elements are used in image display devices of various electronic devices such as televisions and mobile phones, and have been developed with a view to further improving display quality. Specifically, the improvement in performance of the liquid crystal display element can be achieved not only by the improvement in the driving system and the element structure but also by the structural member used in the element. Among the structural members used in the liquid crystal display device, particularly, a liquid crystal alignment film is one of important materials related to display quality, and in order to meet the demand for higher quality of the liquid crystal display device, the liquid crystal alignment film has been actively studied.
Here, the liquid crystal alignment film is provided on a pair of substrates provided on both sides of the liquid crystal layer of the liquid crystal display element so as to be in contact with the liquid crystal layer, and has a function of aligning liquid crystal molecules constituting the liquid crystal layer with respect to the substrates at a regular pattern. By using a liquid crystal alignment film having high liquid crystal alignment properties, a liquid crystal display element having high contrast and improved afterimage characteristics can be realized (for example, refer to patent documents 1 and 2).
In recent years, in liquid crystal display devices, the frame is reduced to increase the frame width of the display screen. Here, in order to narrow the frame and expand the display area, it is necessary to print a liquid crystal alignment film on the end of the substrate and apply a sealant to the liquid crystal alignment film. In response to this, liquid crystal alignment films having high adhesion to a sealant have also been developed (for example, patent documents 7 to 9).
In the formation of such a liquid crystal alignment film, a solution (varnish) obtained by dissolving a polyamic acid, a soluble polyimide or a polyamic acid ester in an organic solvent has been mainly used. When a liquid crystal alignment film is formed using these varnishes, the varnish is applied to a substrate, and then the coating film is cured by heating or the like to form a polyimide-based liquid crystal alignment film, and if necessary, an alignment treatment suitable for the display mode is performed. As an orientation treatment method, there is known: a rubbing method in which the surface of the alignment film is rubbed with cloth or the like to adjust the direction of the polymer molecules; the photo-alignment method, which imparts anisotropy to the film by irradiating the alignment film with linearly polarized ultraviolet rays to cause photochemical changes such as photodecomposition, photoisomerization, dimerization, etc., has advantages in that the alignment uniformity by the photo-alignment method is high and the alignment treatment is a non-contact alignment treatment method, compared with the rubbing method, and therefore, the following advantages are obtained: the film is not damaged, and the occurrence of display failure of the liquid crystal display element due to dust generation, static electricity and the like can be reduced.
As a liquid crystal alignment film using such a photo-alignment method, for example, patent documents 1 to 5 describe: by using diaminoazobenzene or the like as a raw material and applying a photoisomerization technique, a photoalignment film having a large anchoring energy and good liquid crystal alignment properties is obtained. Patent document 6 describes that: by applying the photodecomposition technique, a photoalignment film having high transparency and good liquid crystal alignment property is obtained.
[ Prior Art literature ]
[ patent literature ]
[ patent document 1] Japanese patent laid-open publication No. 2010-197999
[ patent document 2] International publication No. 2013/157463
[ patent document 3] Japanese patent laid-open publication No. 2005-275364
[ patent document 4] Japanese patent laid-open No. 2007-248637
[ patent document 5] International publication No. 2015/016118
[ patent document 6] Japanese patent laid-open No. 2012-155311
[ patent document 7] Japanese patent laid-open No. 2017-198975
[ patent document 8] International publication No. 2016/043230
[ patent document 9] Japanese patent laid-open publication No. 2018-106096
Disclosure of Invention
[ problem to be solved by the invention ]
In recent years, the use of liquid crystal display elements has been widely used in various fields such as monitors for personal computers, liquid crystal televisions, mobile phones, display units for smart phones, and medical monitors. Further, a more excellent display quality is demanded, and contrast is an important characteristic affecting the display quality. In addition, in a liquid crystal display element using a liquid crystal alignment film using a photo-alignment method, in order to improve the efficiency of manufacturing the liquid crystal display element, it is required to use a liquid crystal alignment film which can exhibit a good contrast even in a short photo-alignment treatment time, that is, a photo-alignment treatment with a small exposure energy.
Accordingly, the present inventors have made an effort to provide a liquid crystal alignment film capable of forming a liquid crystal display element having a good contrast and excellent display quality even when exposure energy of a photo-alignment treatment is smaller than that of the conventional one, and a liquid crystal alignment agent for photo-alignment capable of forming such a liquid crystal alignment film.
[ means of solving the problems ]
The present inventors have found that the above problems can be solved by a liquid crystal aligning agent containing a polyamic acid or derivative thereof, which comprises a raw material composition comprising a compound represented by formula (I) and a compound having a specific structure, and have completed the present invention.
The present invention includes the following structures.
[1] A liquid crystal aligning agent comprising a polyamic acid or a derivative thereof obtained by reacting a tetracarboxylic acid derivative with a diamine, wherein the liquid crystal aligning agent comprises a compound represented by the formula (I) as the tetracarboxylic acid derivative and at least one selected from the group consisting of the formulas (DI-13) and (DI-17-1) as the diamine.
In the formula (I), 1', 2 and 2' are bond, and each is independently bonded to a hydroxyl group, a chlorine atom or an alkoxy group having 1 to 6 carbon atoms, and at least one of the group of 1 and 1 'and the group of 2 and 2' may be bonded to the same oxygen atom;
R b1 、R b2 、R b3 And R is b4 Each independently is a hydrogen atom, or a methyl group, at least one of which is a methyl group.
In the formula (DI-13), R 23 Independently is an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms or a chlorine atom, and p and q are each independently integers of 0 to 4;
in the formula (DI-17-1), k is an integer of 1 to 6.
[2] The liquid crystal aligning agent according to [1], wherein the compound represented by the formula (DI-13) is a compound represented by the formula (DI-13-1), and the compound represented by the formula (DI-17-1) is a compound wherein k is 2 in the formula (DI-17-1).
[3] The liquid crystal aligning agent according to [1] or [2], which comprises a compound represented by the formula (DI-17-2) as a diamine.
In the formula (DI-17-2), e is an integer of 1 to 10, and Boc is t-butoxycarbonyl (tertiary butoxycarbonyl group).
[4] The liquid crystal aligning agent according to [3], wherein in the formula (DI-17-2), e is an integer of 6 to 10.
[5] The liquid crystal aligning agent according to [3], wherein in the formula (DI-17-2), e is 6.
[6] The liquid crystal aligning agent according to any one of [1] to [5], which comprises a polyamic acid or a derivative thereof obtained by reacting a tetracarboxylic acid derivative other than the compound represented by the formula (I) with a diamine.
[7] The liquid crystal aligning agent according to any one of [1] to [6], comprising an additive.
[8] A liquid crystal alignment film formed from the liquid crystal alignment agent according to any one of [1] to [7 ].
[9] A liquid crystal element having the liquid crystal alignment film according to [8 ].
[10] A method for manufacturing a liquid crystal alignment film, comprising: a step of coating the liquid crystal aligning agent according to any one of [1] to [7] on a substrate; calcining the substrate; and irradiating the substrate with polarized ultraviolet rays.
[ Effect of the invention ]
By using the liquid crystal aligning agent for photo-alignment of the present invention, a liquid crystal alignment film having high liquid crystal alignment properties can be obtained even when the exposure energy for photo-alignment treatment is small. Further, by using the liquid crystal alignment film, a liquid crystal display element having a good contrast and excellent display quality can be efficiently manufactured.
Detailed Description
The present invention will be described in detail below. The following description of the structural elements is based on the representative embodiments or specific examples, but the present invention is not limited to such embodiments. In the present invention, the "liquid crystal aligning agent" is a liquid crystal aligning agent which can impart anisotropy by irradiation of polarized ultraviolet rays when a film of the liquid crystal aligning agent is formed on a substrate, and is sometimes referred to as a "liquid crystal aligning agent" in the present specification, if it is also simply referred to as a "liquid crystal aligning agent" in some cases. In the present invention, the term "tetracarboxylic acid derivative" means a tetracarboxylic dianhydride, a tetracarboxylic diester, or a tetracarboxylic diester dihalide. The tetracarboxylic acid diester and the tetracarboxylic acid diester dihalide are also sometimes referred to as derivatives of tetracarboxylic acid dianhydride. In the present invention, the diamine and dihydrazide may be referred to as "diamine". The chemical formula in the present specification represents a bond.
< liquid Crystal alignment agent for photo-alignment of the invention >
The liquid crystal aligning agent for photo-alignment of the present invention comprises at least one polymer selected from the group consisting of polyamic acid and polyamic acid derivatives, which is obtained by reacting tetracarboxylic acid derivatives with diamines, and is characterized by comprising at least one compound represented by formula (I) and at least one compound selected from the group consisting of formula (DI-13) and formula (DI-17-1) as raw materials of the polymer. The polymer is sometimes referred to as the polymer of the present invention. The polyamic acid derivative in the present invention refers to polyimide, partially polyimide, polyamic acid ester, polyamic acid-polyamide copolymer, and polyamideimide.
< Polymer species >)
The polyamic acid and the polyamic acid derivative will be described in detail below.
Here, the polyamic acid is a polymer synthesized by polymerization reaction of tetracarboxylic dianhydride represented by formula (AN) and diamine represented by formula (DI), and has a structural unit represented by formula (PAA). When the liquid crystal alignment agent containing the polyamic acid is heated and calcined in the step of forming the liquid crystal alignment film, the polyamic acid is imidized, and a polyimide liquid crystal alignment film having a structural unit represented by the formula (PI) can be formed.
In the formula (AN), the formula (PAA) and the formula (PI), X 1 Is tetravalent organic radical. In the formula (DI), the formula (PAA) and the formula (PI), X 2 Is a divalent organic radical. Regarding X 1 The preferred range and specific examples of the tetravalent organic group in (b) can be referred to the structure corresponding to tetracarboxylic dianhydride described in the present specification. Regarding X 2 The preferable range and specific examples of the divalent organic group in (b) may be referred to the description relating to the structure corresponding to the diamine or dihydrazide described in the column of diamines described in the present specification.
The polyamic acid derivative is a compound having modified properties by substituting a part of the polyamic acid with another atom or group of atoms, and particularly preferably has improved solubility in a solvent used for a liquid crystal aligning agent. Specific examples of such polyamic acid derivatives include: a polyamide-acid-polyamide copolymer obtained by 1) a polyimide obtained by subjecting all amino groups and carboxyl groups of a polyamide acid to a dehydration ring-closure reaction, 2) a partial polyimide obtained by partially subjecting the polyamide acid to a dehydration ring-closure reaction, 3) a polyamide acid ester obtained by converting the carboxyl groups of the polyamide acid into esters, 4) a polyamide acid-polyamide copolymer obtained by substituting a part of the acid dianhydride contained in a tetracarboxylic acid dianhydride compound with an organic dicarboxylic acid and reacting, and 5) a polyamide imide obtained by subjecting a part or all of the polyamide acid-polyamide copolymer to a dehydration ring-closure reaction. Among these derivatives, for example, polyimide having a structural unit represented by the formula (PI) is exemplified, and polyamic acid ester having a structural unit represented by the following formula (PAE) is exemplified.
In the formula (PAE), X 1 Is tetravalent organic radical, X 2 Is a divalent organic radical, Y is independently an alkyl radical. Regarding X 1 、X 2 Reference is made to X in the formula (PAA) 1 、X 2 And (5) related records. Y is preferably a linear or branched alkyl group having 1 to 6 carbon atoms, more preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group or a tert-butyl group.
The tetracarboxylic dianhydride and the diamine used for the synthesis of the polyamic acid may be either one or two or more.
In the case where the polyamic acid of the present invention is a polyimide as a polyamic acid derivative, the obtained polyamic acid solution is subjected to imidization reaction at a temperature of 20 to 150 ℃ together with an acid anhydride such as acetic anhydride, propionic anhydride, trifluoroacetic anhydride or the like as a dehydrating agent, and a tertiary amine such as triethylamine, pyridine, tripyridine or the like as a dehydrating ring-closing catalyst. Alternatively, polyimide may be obtained by precipitating polyamic acid from the obtained polyamic acid solution using a large amount of a poor solvent (an alcohol-based solvent such as methanol, ethanol, isopropanol, or a glycol-based solvent), and imidizing the precipitated polyamic acid in a solvent such as toluene, xylene, or the like together with the dehydrating agent and the dehydration ring-closure catalyst at a temperature of 20 to 150 ℃.
In the imidization reaction, the ratio of the dehydrating agent to the dehydration ring-closing catalyst is preferably 0.1 to 10 (molar ratio). The total amount of the dehydrating agent and the dehydration ring-closure catalyst is preferably 1.5 to 10 times by mol based on the total amount of the molar amounts of the tetracarboxylic dianhydride used for the synthesis of the polyamic acid. By adjusting the amount of the dehydrating agent, the catalyst, the reaction temperature and the reaction time used in the imidization reaction, the degree of imidization can be controlled, and thus a part of polyimide obtained by imidizing only a part of polyamic acid can be obtained. The polyimide obtained may be used as a liquid crystal aligning agent by being separated from a solvent used in the reaction and redissolved in another solvent, or may be used as a liquid crystal aligning agent without being separated from the solvent.
The polyamic acid ester can be obtained by the following method: a method of synthesizing the polyamide acid by reacting the polyamide acid with a hydroxyl group-containing compound, a halide, an epoxy group-containing compound, or the like, or a method of synthesizing the polyamide acid by reacting a tetracarboxylic diester derived from a tetracarboxylic dianhydride or a tetracarboxylic diester dichloride with diamines. The tetracarboxylic acid diester derived from the tetracarboxylic acid dianhydride can be obtained, for example, by reacting the tetracarboxylic acid dianhydride with 2 equivalents of an alcohol and ring-opening, and the tetracarboxylic acid diester dichloride can be obtained by reacting the tetracarboxylic acid diester with 2 equivalents of a chlorinating agent (for example, thionyl chloride, etc.). The polyamic acid ester may have only an amic acid ester structure, or may be a partially esterified product in which an amic acid structure and an amic acid ester structure coexist.
The polyamic acid or derivative thereof of the present invention can be produced in the same manner as known polyamic acid or derivative thereof used for forming a polyimide film. The total amount of the tetracarboxylic acid derivatives added is preferably 0.9 to 1.1 mol based on 1 mol of the total of the diamines.
The liquid crystal aligning agent of the present invention may contain only one kind of these polyamic acids, polyamic acid esters, and polyimides obtained by imidizing these, or may contain two or more kinds.
The molecular weight of the polyamic acid or derivative thereof of the present invention is preferably 5,000 ~ 500,000, more preferably 5,000 to 50,000, in terms of weight average molecular weight (Mw) in terms of polystyrene. The molecular weight of the polyamic acid or derivative thereof can be determined by measurement by gel permeation chromatography (gel permeation chromatography, GPC).
The polyamic acid or derivative thereof of the present invention can be confirmed for its presence by the following means: the solid component obtained by precipitation in a large amount of poor solvent was analyzed by infrared spectroscopy (infrared spectroscopy, IR) and nuclear magnetic resonance analysis (Nuclear Magnetic Resonance, NMR). In addition, the monomers used can be confirmed by: the polyamic acid or its derivative is decomposed with an aqueous solution of a strong base such as KOH or NaOH by gas chromatography (Gas Chromatography, GC), high performance liquid chromatography (High Performance Liquid Chromatography, HPLC) or gas chromatography mass spectrometry (Gas Chromatography-Mass Spectrometry, GC-MS), and then the extract extracted from the decomposed product is analyzed with an organic solvent.
< tetracarboxylic acid derivative >)
The polymer of the present invention contains a compound represented by the formula (I) as a raw material, and may contain a tetracarboxylic acid derivative other than the compound. Specific examples of the compounds represented by the following formula (I) and other tetracarboxylic acid derivatives are described below.
< Compound represented by formula (I) >)
The compound represented by the formula (I) used in the raw material of the polymer of the present invention will be described.
In the formula (I), 1', 2 and 2' are bond, and each is independently bonded to a hydroxyl group, a chlorine atom or an alkoxy group having 1 to 6 carbon atoms, and at least one of the group of 1 and 1 'and the group of 2 and 2' may be bonded to the same oxygen atom;
R b1 、R b2 、R b3 and R is b4 Each independently is a hydrogen atom, or a methyl group, at least one of which is a methyl group.
Specific examples of the alkoxy group having 1 to 6 carbon atoms include: methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, or tert-butoxy. Methoxy is preferred in terms of the ease of imidization.
The formula (I) comprises: the form in which all four bond bonds are bonded to any one of a hydroxyl group, a chlorine atom, an alkoxy group having 1 to 6 carbon atoms, the form in which any one of a group having 1 to 1 'and a group having 2 to 2' is bonded to the same oxygen atom and two bond bonds in the remaining group are bonded to any one of a hydroxyl group, a chlorine atom, an alkoxy group having 1 to 6 carbon atoms, and the form in which both of a group having 1 to 1 'and a group having 2 to 2' are bonded to the same oxygen atom. Preferably, all four bonds are bonded to any one of a hydroxyl group, a chlorine atom, and an alkoxy group having 1 to 6 carbon atoms, and both of a group of 1 and 1 'and a group of 2 and 2' are bonded to the same oxygen atom.
From the viewpoint of obtaining a liquid crystal alignment film having high sensitivity, R is preferable b1 R is R b4 Is methyl, R b2 R is R b3 Is hydrogen.
Preferred examples of the compound represented by the formula (I) are listed below.
In the formulae (I-2) to (I-5), R 11 Independently an alkyl group having 1 to 6 carbon atoms. R is R 11 Preferably methyl.
By using the compound represented by the formula (I), a liquid crystal aligning agent capable of forming a liquid crystal alignment film having high liquid crystal alignment properties even when the exposure energy for the photo-alignment treatment is small can be obtained.
In the polymer of the present invention, the compound represented by the formula (I) is preferably used in an amount of 50 mol% or more based on the total amount of the tetracarboxylic acid derivative used. A plurality of compounds represented by the formula (I) may also be used in combination.
< tetracarboxylic acid derivatives other than formula (I) >)
The tetracarboxylic acid derivatives represented by the following formulas (AN-1) to (AN-9), (AN-10-1), (AN-10-2), (AN-11), (AN-12), (AN-15) and (AN-16-1) to (AN-16-19) are described as the tetracarboxylic acid derivatives other than the formula (I). These tetracarboxylic dianhydrides can also be derivatized to form tetracarboxylic diesters or tetracarboxylic diester dichlorides for use as starting materials for polymers.
[ tetracarboxylic dianhydride represented by the formula (AN-1) ]
In the formula (AN-1), G 11 Is a single bond, an alkylene group having 1 to 12 carbon atoms, a 1, 4-phenylene group, a 1, 4-cyclohexylene group, or a compound of the formula (G11-1). R is R 11 Independently a hydrogen atom or a methyl group.
In the formula (G11-1), X is independently a single bond, -O-, -S-, or-NR 1 -,R 1 A hydrogen atom or an alkyl group having 1 to 4 carbon atoms, n is independently an integer of 1 to 5, m is an integer of 1 to 3, and a group whose bonding position is not fixed to any carbon atom constituting a ring represents any carbon capable of bonding to the ring.
The tetracarboxylic dianhydride represented by the following formula (AN-1) is exemplified.
In the formula (AN-1-2) and the formula (AN-1-5), m is AN integer of 1 to 12 independently.
[ tetracarboxylic dianhydride represented by the formula (AN-2) ]
In the formula (AN-2), G 11 Is a single bond, an alkylene group having 1 to 12 carbon atoms, a 1, 4-phenylene group, or a 1, 4-cyclohexylene group. X is X 11 Is a single bond or-CH 2 -。G 12 Independently any of the following trivalent radicals.
At G 12 When > N-, G 11 Not a single bond or-CH 2 -,X 11 Is not a single bond.
The tetracarboxylic dianhydride represented by the following formula (AN-2) is exemplified.
In the formula (AN-2-1), m is AN integer of 1 to 12.
[ tetracarboxylic dianhydride represented by the formula (AN-3) ]
In the formula (AN-3), the ring A 11 Is cyclohexane ring or benzene ring.
Examples of the tetracarboxylic dianhydride represented by the formula (AN-3) include compounds represented by the following formulas (AN-3-1) and (AN-3-2).
[ tetracarboxylic dianhydride represented by the formula (AN-4) ]
In the formula (AN-4), G 13 Is a single bond, - (CH) 2 ) m -、-O-、-S-、-C(CH 3 ) 2 -、-SO 2 -、-CO-、-C(CF 3 ) 2 Or a divalent group represented by the following formula (G13-1), m being an integer of 1 to 12. Ring A 11 Each independently is a cyclohexane ring or a benzene ring. G 13 Can be bonded to ring A 11 Is a part of the first group of the second group of the third.
In the formula (G13-1), G 13a G (G) 13b Each independently is a divalent group represented by a single bond, -O-, -CONH-, or-NHCO-. The phenylene group is preferably a 1, 4-phenylene group or a 1, 3-phenylene group.
Examples of the tetracarboxylic dianhydride represented by the formula (AN-4) include compounds represented by the following formulas (AN-4-1) to (AN-4-31).
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In the formula (AN-4-17), m is AN integer of 1 to 12.
[ tetracarboxylic dianhydride represented by the formula (AN-5) ]
In the formula (AN-5), R 11 Independently a hydrogen atom or a methyl group. Two R 11 R on the medium benzene ring 11 Is bonded to any of the positions of the benzene ring which can be substituted.
Examples of the tetracarboxylic dianhydride represented by the formula (AN-5) include compounds represented by the following formulas (AN-5-1) to (AN-5-3).
[ tetracarboxylic dianhydride represented by the formula (AN-6) ]
In the formula (AN-6), X 11 Independently a single bond or-CH 2 -。X 12 is-CH 2 -、-CH 2 CH 2 -or-ch=ch-. n is 1 or 2. When n is 2, two X 12 May be the same as or different from each other.
Examples of the tetracarboxylic dianhydride represented by the formula (AN-6) include compounds represented by the following formulas (AN-6-1) to (AN-6-12).
[ tetracarboxylic dianhydride represented by the formula (AN-7) ]
In the formula (AN-7), X 11 Is a single bond or-CH 2 -。
Examples of the tetracarboxylic dianhydride represented by the formula (AN-7) include compounds represented by the following formulas (AN-7-1) and (AN-7-2).
[ tetracarboxylic dianhydride represented by the formula (AN-8) ]
In the formula (AN-8), X 11 Is a single bond or-CH 2 -。R 12 Is a hydrogen atom, methyl, ethyl, or phenyl. Ring A 12 Is cyclohexane or cyclohexene.
Examples of the tetracarboxylic dianhydride represented by the formula (AN-8) include compounds represented by the following formulas (AN-8-1) and (AN-8-2).
[ tetracarboxylic dianhydride represented by the formula (AN-9) ]
In the formula (AN-9), r is 0 or 1 independently.
Examples of the tetracarboxylic dianhydride represented by the formula (AN-9) include compounds represented by the following formulas (AN-9-1) to (AN-9-3).
[ tetracarboxylic dianhydride represented by the formula (AN-10-1) and the formula (AN-10-2) ]
[ tetracarboxylic dianhydride represented by the formula (AN-11) ]
In the formula (AN-11), the ring A 11 Independently a cyclohexane ring or a benzene ring.
As examples of the tetracarboxylic dianhydride represented by the formula (AN-11), compounds represented by the following formulas (AN-11-1) to (AN-11-3) can be given.
[ tetracarboxylic dianhydride represented by the formula (AN-12) ]
In the formula (AN-12), the ring A 11 Each independently is a cyclohexane ring or a benzene ring.
As examples of the tetracarboxylic dianhydride represented by the formula (AN-12), compounds represented by the following formulas (AN-12-1) to (AN-12-3) can be given.
[ tetracarboxylic dianhydride represented by the formula (AN-15) ]
In the formula (AN-15), w is AN integer of 1 to 10.
As examples of the tetracarboxylic dianhydride represented by the formula (AN-15), compounds represented by the following formulas (AN-15-1) to (AN-15-3) can be given.
[ tetracarboxylic dianhydrides represented by the formulae (AN-16-1) to (AN-16-19) ]
As the tetracarboxylic dianhydride other than the above, compounds represented by the following formulas (AN-16-1) to (AN-16-19) are mentioned.
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Suitable materials for improving the respective characteristics of the liquid crystal alignment film among the tetracarboxylic dianhydrides will be described. In the case where importance is attached to improving the sealing property, it is preferable to use the compound represented by the formula (AN-2). In the formula (AN-2), G is preferable 12 Compounds which are > CH-. As a specific example, the compounds represented by the formulas (AN-2-1) to (AN-2-4) are preferable, and the compound represented by the formula (AN-2-2) is more preferable.
< diamines >
The polymer of the present invention contains at least one compound selected from the group consisting of the formula (DI-13) and the formula (DI-17-1) as a raw material, and may further contain diamines other than the above. Specific examples of the compound represented by the following formula (DI-13) or (DI-17-1) and diamines other than the compound are described below.
H 2 N-G 20 NH 2 (DI-1)
In the formula (DI-1), G 20 Is an alkylene group having 1 to 12 carbon atoms or a group represented by the formula (DI-1-a). At G 20 In the case of C1-12 alkylene, -CH 2 At least one of them may be substituted by-NH-or-O-but they are not adjacent, -CH 2 At least one hydrogen atom may be substituted by hydroxy or methyl.
In the formula (DI-1-a), v is an integer of 1 to 6 independently of each other.
In the formula (DI-3), the formula (DI-6) and the formula (DI-7), G 21 Independently a single bond, -NH-, -NCH 3 -、-O-、-S-、-S-S-、-SO 2 -、-CO-、-COO-、-CONCH 3 -、-CONH-、-C(CH 3 ) 2 -、-C(CF 3 ) 2 -、-(CH 2 ) m -、-O-(CH 2 ) m -O-、-N(CH 3 )-(CH 2 ) k -N(CH 3 )-、-(O-C 2 H 4 ) m -O-、-O-CH 2 -C(CF 3 ) 2 -CH 2 -O-、-O-CO-(CH 2 ) m -CO-O-、-CO-O-(CH 2 ) m -O-CO-、-(CH 2 ) m -NH-(CH 2 ) m -、-CO-(CH 2 ) k -NH-(CH 2 ) k -、-(NH-(CH 2 ) m ) k -NH-、-CO-C 3 H 6 -(NH-C 3 H 6 ) n -CO-, or-S- (CH) 2 ) m -S-, m is independently an integer from 1 to 12, k is an integer from 1 to 5, n is 1 or 2.
In the formula (DI-4), s is independently an integer of 0 to 2.
In the formula (DI-5), G 33 Is a single bond, -NH-, -NCH 3 -、-O-、-S-、-S-S-、-SO 2 -、-CO-、-COO-、-CONCH 3 -、-CONH-、-C(CH 3 ) 2 -、-C(CF 3 ) 2 -、-(CH 2 ) m -、-O-(CH 2 ) m -O-、-(O-C 2 H 4 ) m -O-、-O-CH 2 -C(CF 3 ) 2 -CH 2 -O-、-O-CO-(CH 2 ) m -CO-O-、-CO-O-(CH 2 ) m -O-CO-、-(CH 2 ) m -NH-(CH 2 ) m -、-CO-(CH 2 ) k -NH-(CH 2 ) k -、-CO-C 3 H 6 -(NH-C 3 H 6 ) n -CO-, or-S- (CH) 2 ) m -S-、-N(Boc)-(CH 2 ) e -、-(CH 2 ) m -N(Boc)-CONH-(CH 2 ) m -、-(CH 2 ) m -N(Boc)-(CH 2 ) m -, or a group represented by the following formula (DI-5-a) or the following formula (DI-5-b), m is independently an integer of 1 to 12, k is an integer of 1 to 5, e is an integer of 2 to 10, and n is 1 or 2.Boc is tert-butoxycarbonyl.
In the formula (DI-5-a), q is an integer of 0 to 6 independently of each other. R is R 44 Is a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.
In the formula (DI-6) and the formula (DI-7), G 22 Independently a single bond, -O-, -S-, -CO-, -C (CH) 3 ) 2 -、-C(CF 3 ) 2 -, a part of or an alkylene group having 1 to 10 carbon atoms.
At least one hydrogen atom of the cyclohexane ring and the benzene ring in the formulae (DI-2) to (DI-7) may be an alkyl group having 1 to 3 carbon atoms through a fluorine atom, a chlorine atom Substituted by methoxy, hydroxy, trifluoromethyl, carboxyl, carbamoyl, phenylamino, phenyl or benzyl, and in the formula (DI-4), at least one hydrogen atom of the cyclohexane ring and the benzene ring may be substituted by one selected from the group consisting of groups represented by any one of the following formulas (DI-4-a) to (DI-4-i), in the formula (DI-5), G 33 In the case of a single bond, at least one hydrogen atom of the benzene ring may be bonded via NHBoc or N (Boc) 2 And (3) substitution.
In the formula (DI-4-a) and the formula (DI-4-b), R 20 Independently a hydrogen atom or a methyl group. In the formula (DI-4-f) and the formula (DI-4-g), m is an integer of 0 to 12, and Boc is tert-butoxycarbonyl.
In the formulae (DI-2) to (DI-7), the group whose bonding position is not fixed to the carbon atom constituting the ring means that the bonding position in the ring is arbitrary.
In the formula (DI-11), r is 0 or 1. In the formulae (DI-8) to (DI-11), the bonding position of the amino group bonded to the ring is arbitrary.
In the formula (DI-12), R 21 R is R 22 Each independently is an alkyl group having 1 to 3 carbon atoms or a phenyl group, G 23 Independently is an alkylene group having 1 to 6 carbon atoms, a phenylene group or an alkyl-substituted phenylene group, and w is an integer of 1 to 10.
In the formula (DI-13), R 23 Independently is an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms or a chlorine atom, and p and q are each independently integers of 0 to 4.
In the formula (DI-14), ring B is a monocyclic heterocyclic aromatic group, R 24 Is a hydrogen atom, a fluorine atom,Chlorine atom, alkyl group, alkoxy group, alkenyl group or alkynyl group having 1 to 6 carbon atoms, q is independently an integer of 0 to 4. When q is 2 or more, a plurality of R 24 May be the same as or different from each other. In the formula (DI-15), the ring C is a heterocyclic aromatic group or a heterocyclic aliphatic group. In the formula (DI-16), G 24 Is a single bond, an alkylene group having 2 to 6 carbon atoms or a 1, 4-phenylene group, and r is 0 or 1.
In the formula (DI-17), R 23 Independently is an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms or a chlorine atom, p is independently an integer of 0 to 4, R 25 Independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a tert-butoxycarbonyl group, Z is a divalent group comprising an alkylene group having 1 to 10 carbon atoms. In the alkylene group having 1 to 10 carbon atoms, CH is at any position and in any number 2 May be substituted with NH, but NH is not adjacent.
R 25 A preferable example of the alkyl group having 1 to 4 carbon atoms is a methyl group. A preferable example of the divalent group containing an alkylene group having 1 to 10 carbon atoms in Z is- (CH) 2 ) m -、-Ph-(CH 2 ) m Ph-, m is an integer from 1 to 10. Among these, preferred is- (CH) 2 ) m -, further preferably- (CH) 2 ) 2 - (ethylene group). Here, ph is 1, 4-phenylene.
In the formulae (DI-13) to (DI-17), a group whose bonding position is not fixed to a carbon atom constituting a ring indicates that the bonding position in the ring is arbitrary. The bonding positions of the amino groups on the rings at both ends may be arbitrary, but are preferably para and meta, and more preferably para.
In the formula (DIH-1), G 25 Is a single bond, alkylene group with 1-20 carbon atoms, -CO-, -O-, -S-, -SO 2 -、-C(CH 3 ) 2 -, or-C (CF) 3 ) 2 -。
In the formula (DIH-2), the ring D is a cyclohexylene group, a phenylene group or a naphthylene group, at least one hydrogen atom of the group being substituted by a methyl group, an ethyl group or a phenyl group.
In the formula (DIH-3), each ring E is independently cyclohexylene, or phenylene, at least one hydrogen atom of the group being substituted by methyl, ethyl, or phenyl. The two rings E may be identical or different from each other. Y is a single bond, alkylene of 1-20 carbon atoms, -CO-, -O-, -S-, -SO 2 -、-C(CH 3 ) 2 -, or-C (CF) 3 ) 2 -. In the formulae (DIH-2) and (DIH-3), the bond position of the-hydrazide group bonded to the ring is arbitrary.
Examples of the diamine represented by the formula (DI-1) are shown in the following formulas (DI-1-1) to (DI-1-9).
In the formula (DI-1-7) and the formula (DI-1-8), k is an integer of 1 to 3, respectively. In the formula (DI-1-9), v is an integer of 1 to 6 independently of each other.
Examples of the diamines represented by the following formulas (DI-2) to (DI-3) are shown in the following formulas (DI-2-1), (DI-2-2) and (DI-3-3) of the formulas (DI-3-3).
Examples of the diamine represented by the formula (DI-4) are shown in the following formulas (DI-4-1) to (DI-4-27).
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In the formula (DI-4-20) and the formula (DI-4-21), m is an integer of 1 to 12, respectively.
An example of the diamine represented by the formula (DI-5) is shown below.
In the formula (DI-5-1), m is an integer of 1 to 12.
In the formula (DI-5-12) and the formula (DI-5-13), m is an integer of 1 to 12, respectively.
In the formula (DI-5-16), v is an integer of 1 to 6.
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In the formulae (DI-5-35) to (DI-5-37), m is an integer of 1 to 12, in the formula (DI-5-38), k is an integer of 1 to 5, in the formula (DI-5-40), and n is an integer of 1 or 2.
In the formula (DI-5-44), e is an integer of 2 to 10, R in the formula (DI-5-45) 43 Is a hydrogen atom, (tert-butoxycarbonyl) amino group, or bis (tert-butoxycarbonyl) amino group.
Examples of the diamine represented by the formula (DI-6) are shown in the following formulas (DI-6-1) to (DI-6-7).
Examples of the diamine represented by the formula (DI-7) are shown in the following formulas (DI-7-1) to (DI-7-11).
In the formula (DI-7-3) and the formula (DI-7-4), m is an integer of 1 to 12, and n is 1 or 2.
Examples of the diamine represented by the formula (DI-8) are shown in the following formulas (DI-8-1) to (DI-8-4).
Examples of the diamine represented by the formula (DI-9) are shown in the following formulas (DI-9-1) to (DI-9-3).
Examples of the diamine represented by the formula (DI-10) are shown in the following formulas (DI-10-1) and (DI-10-2).
Examples of the diamine represented by the formula (DI-11) are shown in the following formulas (DI-11-1) to (DI-11-3).
An example of the diamine represented by the formula (DI-12) is shown in the following formula (DI-12-1).
Examples of the diamine represented by the formula (DI-13) are shown in the following formulas (DI-13-1) to (DI-13-13).
Examples of the diamine represented by the formula (DI-14) are shown in the following formulas (DI-14-1) to (DI-14-9).
Examples of the diamine represented by the formula (DI-15) are shown in the following formulas (DI-15-1) to (DI-15-12).
An example of the diamine represented by the formula (DI-16) is shown in the following formula (DI-16-1).
An example of the diamine represented by the formula (DI-17) is shown below.
In the formula (DI-17-1), k is an integer of 1 to 6. In the formulae (DI-17-2) to (DI-17-3), e is an integer of 1 to 10, and Boc is tert-butoxycarbonyl. In the formula (DI-17-4), m is 1 or 2, and k is 1 or 2, respectively.
Examples of the compounds represented by any of the formulae (DIH-1) to (DIH-3) are shown in the following formulae (DIH-1-1), formula (DIH-1-2), formulae (DIH-2-1) to (DIH-2-3), and formulae (DIH-3-1) to (DIH-3-6).
In the formula (DIH-1-2), m is an integer of 1 to 12.
The use of the compound represented by the formula (DI-13) or (DI-17-1) can improve the afterimage characteristics. Among the compounds represented by the formula (DI-13), the compound represented by the formula (DI-13-1) is preferably used. Of the compounds represented by the formula (DI-17-1), k=2 is more preferable. In the polymer of the present invention, the compound represented by the formula (DI-13) or (DI-17-1) is preferably used in an amount of 10 mol% or more based on the total amount of diamines used. A plurality of compounds represented by the formula (DI-13) or the formula (DI-17-1) may be used in combination.
In addition, when the residual image characteristics are more important, the compound represented by the formula (DI-4-1), the formula (DI-5-1), or the formula (DI-17-2) is preferably used as the diamine. In the formula (DI-5-1), m=2 to 8 is more preferable, and m=4 to 8 is even more preferable.
In particular, the compound represented by the formula (DI-17-2) is preferably used as a raw material for the polymer of the present invention in the form of a polymer other than the polymer of the present invention (a blending type liquid crystal aligning agent described later). In the formula (DI-17-2), e=6 to 10 is more preferable, e=6, 8 or 10 is more preferable, and e=6 is particularly preferable.
In the polymer of the present invention, the compound represented by the formula (DI-4-1), the formula (DI-5-1) or the formula (DI-17-2) is preferably used in an amount of 5 mol% or more based on the total amount of diamines used.
In the raw material composition used as a raw material for the polymer of the present invention, a part of the diamines may be substituted with at least one selected from the group consisting of monoamines and monoazides. The ratio of substitution is preferably in the range of 40 mol% or less of at least one member selected from the group consisting of monoamines and monoazides to diamines. Such substitution can cause termination of the polymerization reaction when the polyamic acid is formed, and further progress of the polymerization reaction can be suppressed. Therefore, by such substitution, the molecular weight of the obtained polymer (polyamic acid or derivative thereof) can be easily controlled, and for example, the coating property of the liquid crystal aligning agent can be improved without impairing the effect of the present invention. The diamine which may be substituted with monoamine or monoazide may be one kind or two or more kinds as long as the effects of the present invention are not impaired. Examples of the monoamine include: aniline, 4-hydroxyaniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-eicosylamine, p-aminophenyltrimethoxysilane, and 3-aminopropyltriethoxysilane.
In the case where the polymer of the present invention is a polyamic acid or derivative thereof, the raw material composition thereof may further contain a monoisocyanate compound as a monomer. By containing a monoisocyanate compound as a monomer, the terminal of the obtained polyamic acid or derivative thereof is modified, and the molecular weight is regulated. By using the terminal-modified polyamic acid or derivative thereof, for example, the coating property of the liquid crystal aligning agent can be improved without impairing the effect of the present invention. From the viewpoint of the above, the content of the monoisocyanate compound in the monomer is preferably 1 to 10 mol% relative to the total amount of diamine and tetracarboxylic dianhydride in the monomer. Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.
The liquid crystal aligning agent of the present invention may contain one kind of the polymer of the present invention, or the polymer of the present invention and a polymer other than the polymer of the present invention may be mixed. In the present specification, a liquid crystal aligning agent containing one of the polymers is sometimes referred to as a single layer liquid crystal aligning agent. A liquid crystal aligning agent in which two or more kinds of the polymers are mixed is sometimes referred to as a blended liquid crystal aligning agent. The blend type liquid crystal aligning agent is particularly used in the case where reliability and other electrical characteristics of the voltage holding ratio (voltage holding ratio, VHR) are emphasized.
The polymer other than the polymer of the present invention used in the blended liquid crystal aligning agent is preferably one or more of polyamic acid and polyamic acid derivatives. The polyamide acid and the polyamide acid derivative as the polymer other than the polymer of the present invention may be described with reference to the polymer of the present invention except that the compound represented by the formula (I) as the raw material composition is not included.
The following describes tetracarboxylic acid derivatives which are preferable as a raw material for polymers other than the polymer of the present invention used in the blended liquid crystal aligning agent.
In the case where enhancement of the transmittance of the liquid crystal display element is important, the compound represented by the formula (AN-1-1), the formula (AN-1-2), the formula (AN-16-19), the formula (AN-3-1), the formula (AN-4-30), the formula (AN-5-1), the formula (AN-7-2), the formula (AN-10-1), the formula (AN-16-3) or the formula (AN-16-4) is preferable, and the compound represented by the formula (AN-1-1) is more preferable. Among the compounds represented by the formula (AN-1-2), a compound in which m=4 or 8 is particularly preferable.
In the case where enhancement of VHR of a liquid crystal display element is important, a compound represented by the formula (AN-1-1), the formula (AN-1-2), the formula (AN-3-1), the formula (AN-4-5), the formula (AN-4-30), the formula (AN-7-2), the formula (AN-10-1), the formula (AN-16-3), the formula (AN-16-4), the formula (AN-16-17) or the formula (AN-16-19) is preferable, and in the formula (AN-1-2), m=4 or 8 is preferable.
As one of the methods for preventing the burn-in, it is effective to reduce the volume resistance value of the liquid crystal alignment film to increase the relaxation rate of the residual charge (DC) in the liquid crystal alignment film. In the case where the above object is emphasized, the compound represented by the formula (AN-2-10), the formula (AN-3-2), the formula (AN-4-21), the formula (AN-4-29) or the formula (AN-11-3) is preferable.
Of these, the compound represented by the formula (AN-1-1), the formula (AN-2-10), the formula (AN-6-19), the formula (AN-3-2) or the formula (AN-4-21) is more preferable, and the compound represented by the formula (AN-1-1), the formula (AN-2-10) or the formula (AN-3-2) is more preferable.
The following describes diamines which are preferable as raw materials for polymers other than the polymers of the present invention used in the blended liquid crystal aligning agent.
In the case where improvement of the liquid crystal alignment property is important, the compound represented by the formula (DI-5-1), the formula (DI-5-12), the formula (DI-5-13), or the formula (DI-7-3) is preferably used. In the formula (DI-5-1), m=2 to 8 is preferable, and m=4 to 8 is more preferable. In the formula (DI-5-12), m=2 to 6 is preferable, and m=5 is more preferable. In the formula (DI-5-13), m=1 or 2 is preferable, and m=1 is more preferable.
In the case where enhancement of transmittance is important, the compound represented by the formula (DI-1-3), the formula (DI-2-1), the formula (DI-5-5), the formula (DI-5-24), or the formula (DI-7-3) is preferably used, and the compound represented by the formula (DI-2-1) is more preferably used. In the formula (DI-5-1), m=2 to 8 is preferable, and m=8 is more preferable. In the formula (DI-7-3), m=2 or 3 is preferable, m=3 and n=1 is more preferable.
In the case where enhancement of VHR of a liquid crystal display element is important, it is preferable to use a compound represented by the formula (DI-2-1), the formula (DI-4-2), the formula (DI-4-10), the formula (DI-4-15), the formula (DI-4-22), the formula (DI-5-1), the formula (DI-5-28), the formula (DI-17-1) or the formula (DI-13-1), and more preferable is a compound represented by the formula (DI-2-1), the formula (DI-5-1) or the formula (DI-13-1). In the formula (DI-5-1), m=1 is preferable. In the formula (DI-17-1), k=2 is preferable.
As one of the methods for preventing burn-in, it is effective to reduce the volume resistance value of the liquid crystal alignment film to increase the relaxation rate of the residual charge (residual DC) in the liquid crystal alignment film. In the case where the above object is emphasized, the compound represented by the formula (DI-4-1), the formula (DI-4-2), the formula (DI-4-10), the formula (DI-4-15), the formula (DI-5-1), the formula (DI-5-12), the formula (DI-5-13), the formula (DI-5-28), the formula (DI-4-20), the formula (DI-4-21) or the formula (DI-16-1) is preferably used, and the compound represented by the formula (DI-4-1), the formula (DI-5-1) or the formula (DI-5-13) is more preferably used. In the formula (DI-5-1), m=2 to 8 is preferable, and m=4 to 8 is more preferable. In the formula (DI-5-12), m=2 to 6 is preferable, and m=5 is more preferable. In the formula (DI-5-13), m=1 or 2 is preferable, and m=1 is more preferable.
Of these, the compound represented by the formula (DI-4-1), the formula (DI-4-2), the formula (DI-4-10), the formula (DI-4-18), the formula (DI-4-19), the formula (DI-5-1), the formula (DI-5-9), the formula (DI-5-28), the formula (DI-13-1) or the formula (DIH-1-2) is more preferable, and the compound represented by the formula (DI-4-1), the formula (DI-4-18), the formula (DI-4-19), the compound represented by m=1 or 2 in the formula (DI-5-1), the compound represented by the formula (DI-5-9), the formula (DI-13-1) or the formula (DIH-1-2) is more preferable.
In the case of using a two-component polymer, there are, for example, the following modes: one of them selects a polymer having excellent properties in terms of liquid crystal aligning ability, and the other selects a polymer having excellent properties for improving the electrical characteristics of a liquid crystal display element, and is suitable for obtaining a liquid crystal aligning agent having a good balance of liquid crystal aligning properties and electrical characteristics.
In this case, by controlling the structure and molecular weight of each polymer, in the process of forming a thin film by applying a liquid crystal aligning agent obtained by dissolving these polymers in a solvent onto a substrate and predrying the same as described later, a polymer having excellent properties in terms of liquid crystal aligning ability can be segregated in an upper layer of the thin film, and a polymer having excellent properties in terms of improving electrical properties of a liquid crystal display element can be segregated in a lower layer of the thin film. Among the polymers mixed, a phenomenon in which a polymer having low surface energy is separated from an upper layer and a polymer having high surface energy is separated from a lower layer may be used. The confirmation of such layer separation can be confirmed by: the surface energy of the formed liquid crystal alignment film is the same as or similar to the surface energy of a film formed of a liquid crystal alignment agent containing only a polymer intended to segregate in the upper layer.
As a method for exhibiting layer separation, there is also mentioned a method for reducing the molecular weight of a polymer to be segregated in an upper layer.
In the liquid crystal aligning agent containing a mixture of polyamic acid and a polyamic acid derivative, layer separation can be exhibited by using a polymer to be segregated in an upper layer as a polyamic acid ester or polyimide.
The polymer of the present invention can be used as a polymer segregated in the upper layer of the film, a polymer segregated in the lower layer of the film, or two polymers, but more preferably, a polymer segregated in the upper layer of the film.
The polymer other than the polymer of the present invention used in the blended liquid crystal aligning agent is preferably a polymer which is used as a layer segregated in the lower layer of the film.
The proportion of the polyamic acid or derivative thereof segregated in the upper layer of the film is preferably 5 to 80% by weight, and more preferably 20 to 80% by weight, relative to the total amount of the polyamic acid or derivative thereof segregated in the upper layer of the film and the polyamic acid or derivative thereof segregated in the lower layer of the film.
In addition, the liquid crystal aligning agent of the present invention may further contain a solvent in terms of the coatability of the liquid crystal aligning agent or the adjustment of the concentration of the polyamic acid or derivative thereof. The solvent is not particularly limited as long as it is a solvent having an ability to dissolve the polymer component. The solvent may be selected as appropriate depending on the purpose of use, and may be widely used in the production process or the use of a polymer component such as polyamic acid or soluble polyimide. The solvent may be one kind or a mixed solvent of two or more kinds.
The solvent may be a lipophilic solvent of the polyamic acid or a derivative thereof or another solvent for the purpose of improving coatability.
As the aprotic polar organic solvent which is a solvent-philic with respect to the polyamic acid or the derivative thereof, there may be mentioned: n-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl imidazolidinone, N-methyl caprolactam, N-methylpropanamide, N-dimethylacetamide, dimethylsulfoxide, N-dimethylformamide, N-diethylformamide, diethylacetamide, N-dimethylisobutyl amide, gamma-butyrolactone, gamma-valerolactone and the like. Among these solvents, N-methyl-2-pyrrolidone, dimethyl imidazolidone, gamma-butyrolactone, or gamma-valerolactone is preferable.
Examples of other solvents for the purpose of improving coatability and the like include: ethylene glycol monoalkyl ethers such as ethylene glycol monobutyl ether and ethylene glycol mono-t-butyl ether, diethylene glycol monoalkyl ethers such as diethylene glycol monoethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether and diethylene glycol dialkyl ethers such as diethylene glycol butyl methyl ether. In addition, there may be mentioned: propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether and 1-butoxy-2-propanol, dipropylene glycol monoalkyl ethers such as dipropylene glycol monomethyl ether, triethylene glycol monoalkyl ethers, butyl cellosolve acetate, phenyl acetate, and ester compounds such as these acetates. Further, there may be mentioned: dialkyl malonates such as diethyl malonate, alkyl lactate, diisobutyl ketone, diacetone alcohol, 3-methyl-3-methoxybutanol, 4-methyl-2-pentanol, diisobutyl methanol, tetrahydronaphthalene, and isophorone.
Of these solvents, diisobutyl ketone, 4-methyl-2-pentanol, diisobutyl methanol, ethylene glycol monobutyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol monoethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, diethylene glycol butyl methyl ether, 1-butoxy-2-propanol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, or butyl cellosolve acetate is preferable.
The concentration of the solid content in the liquid crystal aligning agent of the present invention is not particularly limited, and the optimum value may be selected by combining the following various coating methods. In general, in order to suppress unevenness, pinholes, and the like at the time of coating, the amount is preferably 0.1 to 30% by weight, more preferably 1 to 10% by weight, relative to the varnish weight.
The viscosity of the liquid crystal aligning agent of the present invention varies depending on the method of coating, the concentration of the polyamic acid or derivative thereof, the kind of the polyamic acid or derivative thereof used, and the kind and ratio of the solvent. For example, when the coating is performed by a printer, the thickness is 5 to 100 mPas (more preferably 10 to 80 mPas). When the thickness is 5 mPas or more, a sufficient film thickness is easily obtained, and when the thickness is 100 mPas or less, printing unevenness is easily suppressed. When the coating is performed by spin coating, it is preferably 5 to 200 mPas (more preferably 10 to 100 mPas). When the coating is performed using an inkjet coating apparatus, it is preferably 5 to 50mpa·s (more preferably 5 to 20mpa·s). The viscosity of the liquid crystal aligning agent can be measured by a rotational viscosity measurement method, for example, using a rotational viscometer (TVE-20L type viscometer manufactured by the east machine industry (Co., ltd.) (measurement temperature: 25 ℃ C.).
The liquid crystal aligning agent of the present invention may further contain various additives. In order to improve various characteristics of the liquid crystal alignment film, various additives may be selectively used according to respective purposes. Examples are shown below.
< alkenyl substituted nadic imide (nadimide) compound >)
For example, the liquid crystal aligning agent of the present invention may further contain an alkenyl-substituted nadic imide compound for the purpose of stabilizing the electric characteristics of the liquid crystal display element for a long period of time. The alkenyl-substituted nadic imide compound may be used singly or in combination. For the above purpose, the content of the alkenyl-substituted nadic imide compound is preferably 1 to 50% by weight, more preferably 1 to 30% by weight, and still more preferably 1 to 20% by weight, relative to the polyamic acid or derivative thereof. The alkenyl-substituted nadic imide compound is preferably a compound soluble in a solvent in which the polyamic acid or derivative thereof used in the present invention is dissolved. Preferred alkenyl-substituted nadic imide compounds include alkenyl-substituted nadic imide compounds disclosed in japanese patent laid-open publication No. 2008-096979, japanese patent laid-open publication No. 2009-109987, and japanese patent laid-open publication No. 2013-242526. As particularly preferred alkenyl-substituted nadic imide compounds, there may be mentioned: bis {4- (allylbicyclo [2.2.1] hept-5-ene-2, 3-dicarboxyimide) phenyl } methane, N '-m-xylylene-bis (allylbicyclo [2.2.1] hept-5-ene-2, 3-dicarboxyimide), or N, N' -hexamethylene-bis (allylbicyclo [2.2.1] hept-5-ene-2, 3-dicarboxyimide).
< Compound having radically polymerizable unsaturated double bond >
For example, the liquid crystal aligning agent of the present invention may further contain a compound having a radical polymerizable unsaturated double bond for the purpose of stabilizing the electrical characteristics of the liquid crystal display element for a long period of time. The compound having a radical polymerizable unsaturated double bond may be one compound or two or more compounds. In addition, the alkenyl-substituted nadic imide compound is not included in the compound having a radical polymerizable unsaturated double bond. Among the compounds having a radical polymerizable unsaturated double bond, preferable compounds include: n, N ' -methylenebisacrylamide, N ' -dihydroxyethylene-bisacrylamide, ethylene bisacrylate, 4' -methylenebis (N, N-dihydroxyethylene-acryiamine), triallyl cyanurate, and compounds having radical-polymerizable unsaturated double bonds disclosed in Japanese patent application laid-open No. 2009-109987, japanese patent application laid-open No. 2013-242526, international publication No. 2014/119682, and International publication No. 2015/152014. For the purpose, the content of the compound having a radical polymerizable unsaturated double bond is preferably 1 to 50% by weight, more preferably 1 to 30% by weight, relative to the polyamic acid or derivative thereof.
< oxazine compound >)
For example, the liquid crystal aligning agent of the present invention may further contain an oxazine compound for the purpose of stabilizing the electrical characteristics of the liquid crystal display element for a long period of time. The oxazine compound may be one compound or two or more compounds. For the above purpose, the content of the oxazine compound is preferably 0.1 to 50% by weight, more preferably 1 to 40% by weight, and still more preferably 1 to 20% by weight, relative to the polyamic acid or derivative thereof.
The oxazine compound is preferably an oxazine compound which is soluble in a solvent for dissolving the polyamic acid or a derivative thereof and has ring-opening polymerization property. Preferable oxazine compounds include oxazine compounds represented by the formula (OX-3-1), the formula (OX-3-9) and the formula (OX-3-10), and oxazine compounds disclosed in Japanese patent application laid-open No. 2007-286597 and Japanese patent application laid-open No. 2013-242526.
< oxazoline Compounds >
For example, the liquid crystal aligning agent of the present invention may further contain an oxazoline compound for the purpose of stabilizing the electrical characteristics of the liquid crystal display element for a long period of time. The oxazoline compound is a compound having an oxazoline structure. The oxazoline compound may be one compound or two or more compounds. For the purpose, the content of the oxazoline compound is preferably 0.1 to 50 wt%, more preferably 1 to 40 wt%, and still more preferably 1 to 20 wt% with respect to the polyamic acid or derivative thereof. Preferred oxazoline compounds include those disclosed in japanese patent application laid-open publication No. 2010-054872 and japanese patent application laid-open publication No. 2013-242526. More preferably, 1, 3-bis (4, 5-dihydro-2-oxazolyl) benzene is exemplified.
< epoxy Compound >
For example, the liquid crystal aligning agent of the present invention may further contain an epoxy compound for the purpose of stabilizing the electrical characteristics of the liquid crystal display element for a long period of time, for the purpose of improving the hardness of the film, or for the purpose of improving the adhesion with the sealant. The epoxy compound may be one kind of compound or two or more kinds of compounds. For the purpose, the content of the epoxy compound is preferably 0.1 to 50% by weight, more preferably 1 to 20% by weight, and still more preferably 1 to 10% by weight, relative to the polyamic acid or derivative thereof.
As the epoxy compound, various compounds having one or more epoxy rings in the molecule can be used.
For the purpose of improving the hardness of the film or the adhesion to the sealant, a compound having two or more epoxy rings in the molecule is preferable, and a compound having three or four epoxy rings in the molecule is more preferable.
Examples of the epoxy compound include those disclosed in Japanese patent application laid-open No. 2009-175715, japanese patent application laid-open No. 2013-242526, japanese patent application laid-open No. 2016-170409, and International publication No. 2017/217813. Preferable epoxy compounds include: n, N, N ', N' -tetraglycidyl-4, 4 '-diaminodiphenylmethane, 3-glycidoxypropyl trimethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltriethoxysilane, (3, 3',4,4 '-diepoxy) dicyclohexyl, 1, 4-butanediol glycidyl ether, tris (2, 3-epoxypropyl) isocyanurate, 1, 3-bis (N, N-diglycidyl aminomethyl) cyclohexane, or N, N' -tetraglycidyl-m-xylylenediamine. More preferable examples thereof include 3-glycidoxypropyl trimethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyl trimethoxysilane and 2- (3, 4-epoxycyclohexyl) ethyl triethoxysilane. In addition to the above, an oligomer or polymer having an epoxy ring may be added. An oligomer or polymer having an epoxy ring can be used as disclosed in Japanese patent application laid-open No. 2013-242526.
< silane Compound >)
For example, the liquid crystal aligning agent of the present invention may further contain a silane compound for the purpose of improving adhesion to a substrate and a sealant. For the above purpose, the content of the silane compound is preferably 0.1 to 30% by weight, more preferably 0.5 to 20% by weight, and still more preferably 0.5 to 10% by weight, relative to the polyamic acid or derivative thereof.
As the silane compound, a silane coupling agent disclosed in Japanese patent application laid-open No. 2013-242526, japanese patent application laid-open No. 2015-212807, japanese patent application laid-open No. 2018-173545, and International publication No. 2018/181566 can be used. As preferred silane coupling agents, there may be mentioned: 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl triethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyl trimethoxysilane, p-aminophenyl trimethoxysilane, 3-aminopropyl triethoxysilane, 3-glycidoxypropyl methyldiethoxysilane, 3-isocyanatopropyl triethoxysilane, or 3-ureidopropyl triethoxysilane.
In addition to the above-described additives, a compound having a cyclic carbonate group, a compound having a hydroxyalkylamide moiety, or a hydroxyl group may be added for the purpose of improving the strength of a liquid crystal alignment film or for the purpose of stabilizing the electrical characteristics of a liquid crystal display element for a long period of time. Specific examples of the compound include those disclosed in Japanese patent laid-open publication No. 2016-118753 and International publication No. 2017/110976. Preferable examples of the compound include the following formulae (HD-1) to (HD-4). These compounds are preferably 0.5 to 50% by weight, more preferably 1 to 30% by weight, and still more preferably 1 to 10% by weight, relative to the polyamic acid or derivative thereof.
In addition, when it is necessary to improve the antistatic property, an antistatic agent may be used, and when imidization is performed at a low temperature, an imidization catalyst may be used. As the imidization catalyst, there may be mentioned imidization catalysts disclosed in Japanese patent application laid-open No. 2013-242526.
< liquid Crystal alignment film >)
The liquid crystal alignment film of the present invention is a film formed by heating the coating film of the liquid crystal alignment agent of the present invention. The liquid crystal alignment film of the present invention can be obtained by a usual method for producing a liquid crystal alignment film from a liquid crystal alignment agent. For example, the liquid crystal alignment film of the present invention can be obtained by a step of forming a coating film of the liquid crystal alignment agent of the present invention, a step of drying by heating, and a step of calcining by heating. The liquid crystal alignment film of the present invention is subjected to a treatment for imparting anisotropy. As the treatment, it is also possible to impart anisotropy by performing a rubbing treatment, but it is preferable to impart anisotropy by irradiation with light.
Hereinafter, a method for forming a liquid crystal alignment film using the liquid crystal alignment agent for photo-alignment of the present invention will be described.
The coating film can be formed by applying the liquid crystal aligning agent of the present invention to a substrate in a liquid crystal display element in the same manner as in the production of a usual liquid crystal alignment film. The substrate may be provided with Indium Tin Oxide (ITO), indium zinc Oxide (In) 2 O 3 ZnO, IZO), indium gallium zinc oxide (In-Ga-ZnO 4 IGZO) electrodes, glass substrates such as color filters, silicon nitride substrates, acrylic substrates, polycarbonate substrates, polyimide substrates, and the like.
As a method of applying a liquid crystal aligning agent to a substrate, a rotator method, a printing method, a dipping method, a dropping method, an inkjet method, and the like are generally known. These methods can be equally applied to the present invention.
As the heat drying step, a method of performing heat treatment in an oven or an infrared oven, a method of performing heat treatment on a hot plate, and the like are generally known. The heat drying step is preferably performed at a temperature within a range where the solvent can evaporate, and more preferably at a temperature relatively lower than the temperature in the heat calcination step. Specifically, the heating and drying temperature is preferably in the range of 30 to 150 ℃, and more preferably in the range of 50 to 120 ℃.
The heating and calcining step may be performed under conditions required for imidization of the polyamic acid or derivative thereof. As a method for calcining a coating film, a method of heat-treating the coating film in an oven or an infrared oven, a method of heat-treating the coating film on a hot plate, and the like are generally known. These methods can be equally applied to the present invention. Generally, the temperature is preferably about 90℃to 300℃and more preferably 120℃to 280℃and still more preferably 150℃to 250 ℃. The calcination time is not particularly limited, but is preferably 1 minute to 2 hours, more preferably 10 minutes to 40 minutes.
The heating may be performed in a plurality of times, and in this case, the temperature may be changed.
In order to orient the liquid crystal in one direction with respect to the horizontal direction and/or the vertical direction, a known photo-alignment method can be suitably used as a method for imparting anisotropy to the liquid crystal alignment film.
As the light used in the light irradiation step in the photo-alignment method, for example, ultraviolet light or visible light including light having a wavelength of 150nm to 800nm can be used. The light is not particularly limited as long as it is light capable of imparting liquid crystal alignment ability to the film, and is preferably polarized light, and more preferably linearly polarized light, when a strong alignment regulating force is to be exerted on the liquid crystal.
The wavelength of the polarized light in the light irradiation step is preferably 150nm to 400nm, more preferably 200nm to 400nm, and still more preferably 200nm to 300nm. The irradiation amount of the polarized light is preferably 0.001J/cm 2 ~10J/cm 2 More preferably 0.1J/cm 2 ~5J/cm 2 . The irradiation angle of the polarized light to the film surface is not particularly limited, and in the case where a strong alignment regulating force for the liquid crystal is to be exhibited, it is preferable that the irradiation angle is as perpendicular as possible to the film surface from the viewpoint of shortening the alignment treatment time. In addition, the liquid crystal alignment film of the present invention can align liquid crystals in a direction perpendicular to the polarization direction of the linearly polarized light by irradiating the linearly polarized light.
As the light source used in the light irradiation step, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a Deep ultraviolet (Deep UV) lamp, a halogen lamp, a metal halide lamp, a high power metal halide lamp, a xenon lamp, a mercury xenon lamp, an excimer lamp, a KrF excimer laser, a fluorescent lamp, a light emitting diode (light emitting diode, LED) lamp, a sodium lamp, a microwave excitation electrodeless lamp (microwave discharged electrodeless lamp), or the like can be used without limitation.
In order to improve the liquid crystal alignment ability of the liquid crystal alignment film, light irradiation may be performed while heating the liquid crystal alignment film. In this case, the heating temperature is preferably in the range of 50℃to 250 ℃.
The light irradiation step may be performed after the heat drying step or after the heat calcination step, and is preferably performed after the heat calcination step. The heat drying step may be performed simultaneously with the heating drying step.
The liquid crystal alignment film of the present invention is preferably additionally heated after the light irradiation step. The heating temperature is preferably 150 to 300 ℃, more preferably 150 to 250 ℃, and even more preferably 200 to 250 ℃ at the same temperature or at a higher temperature than the temperature of the heating and calcining step. The additional heating time is preferably 5 minutes to 2 hours, more preferably 5 minutes to 60 minutes, and still more preferably 5 minutes to 30 minutes.
The cleaning step may be provided after the light irradiation step or after the additional heating step. Specifically, the liquid crystal alignment film is immersed in a solvent. The temperature at the time of impregnation is preferably 10℃to 80℃and more preferably 20℃to 50 ℃. In addition, ultrasonic treatment is also preferable. The treatment time is preferably 1 minute to 1 hour, more preferably 1 minute to 30 minutes. The solvent to be used is not particularly limited as long as it is a solvent that dissolves a decomposed product generated from the liquid crystal alignment film by irradiation with ultraviolet rays, and examples thereof include: water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, cyclohexyl acetate, or the like. Among them, water, 2-propanol, 1-methoxy-2-propanol or ethyl lactate is preferable in terms of versatility and safety. After impregnation, it is preferable to heat or rinse. Or both may be performed. The heating temperature is preferably 150 to 300 ℃, more preferably 200 to 230 ℃. The heating time is preferably 10 seconds to 30 minutes, more preferably 1 minute to 10 minutes. For the rinsing, water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone or other low boiling point solvents are preferable.
The film thickness of the liquid crystal alignment film of the present invention is not particularly limited, but is preferably 10nm to 300nm, more preferably 30nm to 150nm. The film thickness of the liquid crystal alignment film of the present invention can be measured by a known film thickness measuring device such as a profilometer or ellipsometer (ellipsometer).
The liquid crystal alignment film of the present invention can be suitably used for alignment control of a liquid crystal composition in a liquid crystal display element. The liquid crystal composition of the liquid crystal display element can be used for alignment control of liquid crystal materials in all other liquid crystal elements such as liquid crystal antennas, light adjusting windows, optical compensation materials, and variable phase shifters.
< liquid Crystal display element >)
Next, a liquid crystal display element of the present invention will be described. The liquid crystal display device of the present invention is characterized by having the liquid crystal alignment film of the present invention, and can realize high display quality due to the contrast of the liquid crystal alignment film.
The liquid crystal display element of the present invention will be described in detail. In the present invention, the liquid crystal alignment film includes the liquid crystal alignment film of the present invention in a liquid crystal display element including a pair of substrates disposed to face each other, an electrode formed on one or both of the facing surfaces of the pair of substrates, the liquid crystal alignment film formed on the facing surface of each of the pair of substrates, a liquid crystal layer formed between the pair of substrates, and a pair of polarizing films, a backlight, and a driving device provided so as to sandwich the facing substrates.
The electrode is not particularly limited as long as it is an electrode formed on one surface of the substrate. Examples of such electrodes include ITO and metal vapor deposited films. The electrode may be formed on the entire surface of one surface of the substrate, or may be formed in a desired shape, for example, by patterning. Examples of the desired shape of the electrode include a comb-shaped structure and a saw-tooth structure. The electrode may be formed on one of a pair of substrates, or may be formed on both substrates. The formation form of the electrode varies depending on the type of the liquid crystal display element, and for example, in the case of an IPS type liquid crystal display element (in-plane switching type liquid crystal display element), the electrode is disposed on one of the pair of substrates, and in the case of the other liquid crystal display element, the electrode is disposed on both of the pair of substrates. The liquid crystal alignment film is formed on the substrate or electrode.
The liquid crystal layer is formed by sandwiching the liquid crystal composition between the pair of substrates facing each other on the surface on which the liquid crystal alignment film is formed. In the formation of the liquid crystal layer, spacers which are present between the pair of substrates and form appropriate intervals may be used as needed by using fine particles, resin sheets, or the like.
As a method for forming a liquid crystal layer, a vacuum injection method and a liquid crystal Drop Fill (ODF) method are known.
In the vacuum injection method, a gap (cell gap) is provided so that the liquid crystal alignment film faces each other, and a sealing agent is printed while leaving an injection port of liquid crystal, and the substrate is bonded. A liquid crystal display element is manufactured by injecting a filling liquid crystal into a cell gap defined by a substrate surface and a sealant by a vacuum differential pressure, and then closing the injection port.
In the ODF method, crystals are dropped in a region of one of a pair of substrates, which is located outside the liquid crystal alignment film surface Zhou Yinshua, and then the other substrate is bonded so that the liquid crystal alignment film surfaces face each other. Then, the liquid crystal is spread over the entire surface of the substrate by pressing, and the entire surface of the substrate is irradiated with ultraviolet light to cure the sealant, thereby manufacturing a liquid crystal display element.
As the sealant used for bonding the substrates, a UV curing type and a thermosetting type are known. The sealing agent may be printed by, for example, screen printing.
The liquid crystal composition is not particularly limited, and various liquid crystal compositions having positive or negative dielectric anisotropy can be used. Preferred liquid crystal compositions having positive dielectric anisotropy include: liquid crystal compositions disclosed in Japanese patent application laid-open No. 3086228, japanese patent application laid-open No. 2635435, japanese patent application laid-open No. 5-501735, japanese patent application laid-open No. 8-157826, japanese patent application laid-open No. 8-231960, japanese patent application laid-open No. 9-241644 (EP 885272A 1), japanese patent application laid-open No. 9-302346 (EP 806466A 2), japanese patent application laid-open No. 8-199168 (EP 722998A 1), japanese patent application laid-open No. 9-235552, japanese patent application laid-open No. 9-255956, japanese patent application laid-open No. 9-241643 (EP 885271A 1), japanese patent application laid-open No. 10-204016 (EP 844229A 1), japanese patent application laid-open No. 10-204436, japanese patent application laid-open No. 10-231482, japanese patent application laid-open No. 2000-087040, japanese patent application laid-open No. 2001-48822, and the like.
Preferable examples of the liquid crystal composition having negative dielectric anisotropy include: japanese patent application laid-open No. 57-114532, japanese patent application laid-open No. 2-4725, japanese patent application laid-open No. 4-224885, japanese patent application laid-open No. 8-40953, japanese patent application laid-open No. 8-104869, japanese patent application laid-open No. 10-168076, japanese patent application laid-open No. 10-168453, japanese patent application laid-open No. 10-236989, japanese patent application laid-open No. 10-236990, japanese patent application laid-open No. 10-236992, japanese patent application laid-open No. 10-236993, japanese patent application laid-open No. 10-236994, japanese patent application laid-open No. 10-237000, japanese patent application laid-open No. 10-237004, japanese patent application laid-open No. 10-237024, japanese patent application laid-open No. 10-237035, japanese patent application laid-open No. 10-237075, japanese patent application laid-open No. 10-5228 Japanese patent application laid-open No. 10-237076, japanese patent application laid-open No. 10-237448 (EP 967261A 1), japanese patent application laid-open No. 10-287874, japanese patent application laid-open No. 10-287875, japanese patent application laid-open No. 10-291945, japanese patent application laid-open No. 11-029581, japanese patent application laid-open No. 11-080049, japanese patent application laid-open No. 2000-256307, japanese patent application laid-open No. 2001-019965, japanese patent application laid-open No. 2001-192657, japanese patent application laid-open No. 2010-037428, international publication No. 2011/024366, international publication No. 2010/072370, japanese patent application laid-open No. 2010-537010, japanese patent application laid-open No. 2012-077201, A liquid crystal composition disclosed in japanese patent laid-open publication No. 2009-084362 and the like.
Even if one or more optically active compounds are added to a liquid crystal composition having positive or negative dielectric anisotropy, the composition has no influence.
In addition, for example, from the viewpoint of improving the alignment property, the liquid crystal composition used in the liquid crystal display element of the present invention may further contain additives. Such additives are photopolymerizable monomers, optically active compounds, antioxidants, ultraviolet absorbers, pigments, defoamers, polymerization initiators, polymerization inhibitors, and the like. Preferred examples of the photopolymerizable monomer, optically active compound, antioxidant, ultraviolet absorber, pigment, defoamer, polymerization initiator and polymerization inhibitor include those disclosed in International publication No. 2015/146330.
In order to be suitable for a liquid crystal display element of a polymer stabilized alignment (polymer sustained alignment, PSA) mode, a compound capable of polymerizing may be mixed in the liquid crystal composition. Preferable examples of the polymerizable compound are compounds having a polymerizable group such as acrylate, methacrylate, vinyl compound, vinyloxy compound, propenyl ether, epoxy compound (oxetane ), and vinyl ketone. Preferred compounds include those disclosed in International publication No. 2015/146330 and the like.
Examples (example)
The present invention will be described below with reference to examples. The evaluation methods and compounds used in the examples are as follows.
Weight average molecular weight (Mw)
The weight average molecular weight of the polyamic acid was determined by: the sample was measured by GPC using a 2695 separation module 2414 differential refractometer (manufactured by Waters), and converted into polystyrene. The obtained polyamic acid was diluted with a mixed solution of phosphoric acid-Dimethylformamide (DMF) (phosphoric acid/dmf=0.6/100:weight ratio) so that the concentration of the polyamic acid became about 2 wt%. The column was subjected to measurement using HSPgel RT MB-M (manufactured by Waters) and the mixed solution was used as a developing agent at a column temperature of 50℃and a flow rate of 0.40 mL/min. The standard polystyrene used was TSK standard polystyrene manufactured by Tosoh (Stro).
< tetracarboxylic dianhydride >)
< diamine >
< solvent >
NMP: n-methyl-2-pyrrolidone
BC: butyl cellosolve (ethylene glycol monobutyl ether)
Preparation of varnish
Preparation example of varnish A1 preparation
Into a 100mL three-necked flask equipped with stirring vanes and a nitrogen inlet tube, 0.804g of compound 2,016g represented by formula (DI-17-1) and compound 2,016g represented by formula (DI-4-1) and 34.0g of N-methyl-2-pyrrolidone (NMP) were placed and stirred. 3.178g of the compound represented by the formula (I-1) was added to the solution under nitrogen atmosphere, and stirred at room temperature for 12 hours. To this, 30.0g of NMP and 30.0g of BC were added, and the solution was heated and stirred at 60℃until the weight average molecular weight of the polymer as a solute became a desired weight average molecular weight, thereby obtaining varnish A1 having a weight average molecular weight of the solute of about 35,000 and a resin component concentration (solid component concentration) of 6% by weight.
Preparation examples 2 to 17 preparation of varnishes A2 to A10, varnishes R1 to R3 and varnishes B1 to B4
Varnishes A2 to a10, varnishes R1 to R3 and varnishes B1 to B4 were prepared in the same manner as in preparation example 1 except that the compounds used as diamines and tetracarboxylic dianhydrides were changed as shown in tables 1 and 2, and the solid concentration was 6% by weight. In tables 1 and 2, the preparation examples in which two or more compounds are described as diamines means that all the compounds are used as diamines in combination. The values in brackets indicate the formulation ratio (mol%), and blank refers to the absence of the compound corresponding to the column.
TABLE 1
TABLE 2
Example 1
The varnish A1 was diluted and stirred with an NMP/BC mixed solution (NMP/bc=7/3 weight ratio) so that the solid content concentration became 4 weight%, thereby preparing a liquid crystal aligning agent 1. The prepared liquid crystal alignment agent was coated on a glass substrate with FFS electrodes and a glass substrate with column spacers (column spacers) by a rotator method. After the coating, the substrate was heated at 60 ℃ for 80 seconds to evaporate the solvent, and then calcined at 230 ℃ for 30 minutes to form a liquid crystal alignment film. Linear polarization of ultraviolet rays was irradiated from a polarizing plate having a polarization wavelength range of 230nm to 310nm in a direction perpendicular to the substrate using a mliki (Multi-Light) ML-501C/B manufactured by a oxtail motor (stock). At this time, the exposure energy was measured by using an ultraviolet cumulative light meter UIT-150 (light receiver: UVD-S254) manufactured by a cattle tail motor (thigh) to measure the light quantity so as to be "standard exposure amount" 0.5J/cm at a wavelength of 254nm 2 ±0.05J/cm 2 The exposure time of the linear polarization is adjusted by means of the above method. Then, additional heating was performed at 230℃for 30 minutes.
Then, these two substrates on which the liquid crystal alignment films are formed are bonded so that the surfaces on which the liquid crystal alignment films are formed face each other and a gap for injecting the liquid crystal composition is provided between the facing liquid crystal alignment films. At this time, the polarization directions of the linearly polarized light irradiated to the respective liquid crystal alignment films are made parallel. The negative type liquid crystal composition A was injected into the cell to prepare a liquid crystal cell (liquid crystal display element) having a cell thickness of 5. Mu.m.
Negative type liquid crystal composition A >
(physical Property values)
Phase transition temperature NI: dielectric constant anisotropy Δε at 75.7deg.C: -4.1, refractive index anisotropy Δn:0.101, viscosity η:14.5 mPas.
The luminance-voltage characteristic (B-V characteristic) of the produced liquid crystal cell was measured, and the Contrast Ratio (CR) was determined using the following formula. As a result, CR was 3600.
CR=B max /B min
Wherein B is max Representing maximum brightness in B-V characteristics, B min Representing the minimum brightness in the B-V characteristic.
The larger the CR value, the more vivid the dark display, and the better the contrast. When the CR value is 3000 or more, the contrast is good, and when it is 3300 or more, the contrast is excellent.
Then, the amount of light in the linearly polarized light becomes "low exposure" 0.3J/cm which is lower than the standard exposure amount 2 ±0.03J/cm 2 The contrast was obtained in the same manner as in the case of manufacturing a liquid crystal cell except for the adjustment of the exposure time. As a result, CR was 3600.
Examples 2 to 10 and comparative examples 1 to 3
The liquid crystal aligning agent 2 and the comparative aligning agent 1 to comparative aligning agent 3 were prepared by diluting and stirring the liquid crystal using a NMP/BC mixed solution (NMP/bc=7/3 weight ratio) so that the solid concentration became 4 weight% with the varnish A2 and the varnishes R1 to R3. Contrast was evaluated in the same manner as in example 1 except that the liquid crystal aligning agent 1 was replaced with the liquid crystal aligning agent shown in table 3. The evaluation results are shown in table 3 together with example 1.
TABLE 3 Table 3
The examples 1 and 2 show excellent contrast not only at the standard exposure but also at low exposure. On the other hand, in comparative examples 1 and 2, the CR values at the standard exposure amount and the low exposure amount were low. In comparative example 3, good contrast was exhibited at the standard exposure amount, but good contrast was not obtained at the low exposure amount.
Examples 3 to 10
The liquid crystal aligning agents 2 to 10 were prepared by diluting and stirring the liquid crystal aligning agents with NMP/BC mixed solution (NMP/bc=7/3 weight ratio) so that the solid content concentration became 4 weight% using the varnishes A3 to a 10. The liquid crystal aligning agent shown in Table 3 was used in place of the liquid crystal aligning agent 1, and exposure was set to "low exposure" (0.3J/cm) 2 ±0.03J/cm 2 ) Except for this, contrast was evaluated in the same manner as in example 1. The evaluation results are shown in table 4.
TABLE 4 Table 4
Varnish No. Contrast ratio
Example 3 Liquid crystal aligning agent 3 A3 3,600
Example 4 Liquid crystal aligning agent 4 A4 3,500
Example 5 Liquid crystal aligning agent 5 A5 3,500
Example 6 Liquid crystal aligning agent 6 A6 3,500
Example 7 Liquid crystal aligning agent 7 A7 3,500
Example 8 Liquid crystal aligning agent 8 A8 3,500
Example 9 Liquid crystal aligning agent 9 A9 3,500
Example 10 Liquid crystal aligning agent 10 A10 3,500
Example 11
Varnish A3 and varnish B1 were mixed to a weight ratio of 6:4, and further diluting and stirring the mixture of NMP/BC (NMP/bc=7/3 weight ratio) so that the solid content concentration becomes 3.7 weight%, to prepare the liquid crystal aligning agent 11.
The same procedure as in example 3 was repeated except that the liquid crystal aligning agent 11 was used, and the contrast ratio was measured.
Examples 12 to 17 and comparative example 4
Liquid crystal aligning agents 12 to 17 and comparative aligning agent 4 were prepared in the same manner as in example 11, except that the varnishes shown in table 5 were used instead of varnish A3 and varnish B1 and the blending ratios shown in table 5 were changed. Using the prepared liquid crystal aligning agent, contrast was measured in the same manner as in example 1. The varnish, blending ratio and results used are shown in Table 5 together with example 11.
TABLE 5
Regarding the contrast in examples 1 to 17, even when the exposure amount at the time of photo-alignment treatment was 0.3J/cm 2 Such a small energy also shows an excellent value of CR of 3,300 or more. It is found that a liquid crystal alignment film of a liquid crystal display element having a high contrast even when the exposure amount is small can be obtained by using a compound represented by the formula (I) and at least one compound selected from the group consisting of the formulas (DI-13) and (DI-17-1).
[ Industrial applicability ]
When the liquid crystal aligning agent for photo-alignment of the present invention is used, a liquid crystal alignment film of a liquid crystal display element that achieves high contrast even when the exposure energy for photo-alignment treatment is small can be produced. The liquid crystal aligning agent for photo-alignment of the present invention can be suitably used for a transverse electric field type liquid crystal display element.

Claims (10)

1. A liquid crystal aligning agent comprising a polyamic acid or a derivative thereof obtained by reacting a tetracarboxylic acid derivative with a diamine, wherein the liquid crystal aligning agent comprises a compound represented by the formula (I) as the tetracarboxylic acid derivative and at least one selected from the group consisting of the formulas (DI-13) and (DI-17-1) as the diamine,
in the formula (I), 1', 2 and 2' are bond, and each is independently bonded to a hydroxyl group, a chlorine atom or an alkoxy group having 1 to 6 carbon atoms, and at least one of the group of 1 and 1 'and the group of 2 and 2' may be bonded to the same oxygen atom;
R b1 、R b2 、R b3 and R is b4 Each independently is a hydrogen atom, or a methyl group, at least one of which is a methyl group;
in the formula (DI-13), R 23 Independently is an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms or a chlorine atom, and p and q are each independently integers of 0 to 4;
in the formula (DI-17-1), k is an integer of 1 to 6.
2. The liquid crystal aligning agent according to claim 1, wherein the compound represented by the formula (DI-13) is a compound represented by the formula (DI-13-1), the compound represented by the formula (DI-17-1) is a compound wherein k is 2 in the formula (DI-17-1),
3. the liquid crystal aligning agent according to claim 1, comprising a compound represented by the formula (DI-17-2) as a diamine,
In the formula (DI-17-2), e is an integer of 1 to 10, and Boc is a tert-butoxycarbonyl group.
4. The liquid crystal aligning agent according to claim 3, wherein in the formula (DI-17-2), e is an integer of 6 to 10.
5. The liquid crystal aligning agent according to claim 3, wherein in the formula (DI-17-2), e is 6.
6. The liquid crystal aligning agent according to any one of claims 1 to 5, comprising a polyamic acid or a derivative thereof obtained by reacting a tetracarboxylic acid derivative other than the compound represented by the formula (I) with a diamine.
7. The liquid crystal aligning agent according to claim 1, comprising an additive.
8. A liquid crystal alignment film formed from the liquid crystal alignment agent according to any one of claims 1 to 7.
9. A liquid crystal element having the liquid crystal alignment film according to claim 8.
10. A method for manufacturing a liquid crystal alignment film, comprising: a step of coating the liquid crystal aligning agent according to any one of claims 1 to 7 on a substrate; calcining the substrate; and irradiating the substrate with polarized ultraviolet rays.
CN202310297142.8A 2022-04-07 2023-03-24 Liquid crystal aligning agent, liquid crystal alignment film, method for producing liquid crystal alignment film, and liquid crystal element Pending CN116891752A (en)

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JP2022-063842 2022-04-07
JP2023-014013 2023-02-01
JP2023014013A JP2023155156A (en) 2022-04-07 2023-02-01 Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal device using the same

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