Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K19/00—Liquid crystal materials
  • C09K19/52—Liquid crystal materials characterised by components which are not liquid crystals, e.g. additives with special physical aspect: solvents, solid particles
  • C09K19/54—Additives having no specific mesophase characterised by their chemical composition
  • C09K19/56—Aligning agents
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G73/00—Macromolecular compounds obtained by reactions forming a linkage containing nitrogen with or without oxygen or carbon in the main chain of the macromolecule, not provided for in groups C08G12/00 - C08G71/00
  • C08G73/06—Polycondensates having nitrogen-containing heterocyclic rings in the main chain of the macromolecule
  • C08G73/10—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L79/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen or carbon only, not provided for in groups C08L61/00 - C08L77/00
  • C08L79/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
  • C08L79/08—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL 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
  • G02F1/00—Devices 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
  • G02F1/01—Devices 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 
  • G02F1/13—Devices 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
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL 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
  • G02F1/00—Devices 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
  • G02F1/01—Devices 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 
  • G02F1/13—Devices 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
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
  • G02F1/133711—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers by organic films, e.g. polymeric films
  • G02F1/133723—Polyimide, polyamide-imide
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL 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
  • G02F1/00—Devices 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
  • G02F1/01—Devices 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 
  • G02F1/13—Devices 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
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
  • G02F1/133746—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers for high pretilt angles, i.e. higher than 15 degrees

Definitions

• the present invention relates to a liquid crystal alignment agent for obtaining a liquid crystal alignment film, and more particularly, to a liquid crystal alignment agent capable of obtaining a liquid crystal alignment film having a high pretilt angle and excellent liquid crystal alignment. It is. Background art
• liquid crystal display elements have been actively developed due to their excellent display characteristics, and the display performance has been further improved.
• demands for liquid crystal alignment films have also been required to simultaneously improve various characteristics.
• General characteristics required for the liquid crystal alignment film include control of the pretilt angle of liquid crystal molecules, voltage holding ratio, and charge storage characteristics by DC voltage.Of these characteristics, control of the pretilt angle is one of the characteristics. This is a very important property for driving the liquid crystal display element uniformly.
• the pretilt angle of the liquid crystal obtained by such a polymer-based liquid crystal alignment film is generally about 1 to 2 degrees, but a higher pretilt angle can be obtained by introducing an appropriate side chain into the polymer. It has been known.
• Examples of the side chain having the effect of increasing the pretilt angle of the liquid crystal include an alkyl group having 4 to 20 carbon atoms and a fluoroalkyl group (see, for example, Japanese Patent Application Laid-Open No. 2-287270) and a benzene ring-cyclo.
• Cyclic groups such as a xanth ring and a cyclic group having an alkyl group or the like (see, for example, JP-A-3-179332) and a group having a steroid skeleton (for example, JP-A-4-128414) See No. 27.) and others are known.
• the above method controls the pretilt angle by the side chain and obtains from the polymer main chain.
• the value of the pretilt angle can be arbitrarily changed by changing the structure of the side chain and the amount of the introduced side chain.
• the introduction of such side chains considerably disturbs the regulation of liquid crystal alignment by the polymer main chain, and in some cases, lowers the liquid crystal alignment of the produced liquid crystal display device. Occurs.
• the liquid crystal alignment is easily disturbed by heat, and the pretilt angle is easily reduced by heating. The decrease in pretilt angle due to heating greatly reduces the reliability of the liquid crystal display device.
• the rubbing treatment of the liquid crystal alignment film is an important step for defining the alignment direction of the liquid crystal, but there is a problem that dust generated at that time causes display defects. In order to suppress the generation of dust, rubbing treatment conditions have tended to become weaker in recent years.
• the rubbed liquid crystal alignment film is usually washed with ultrapure water or the like in order to remove adhering dust, but an organic solvent such as isopropanol may be used to improve the washing efficiency. is there. In a liquid crystal alignment film having a low liquid crystal alignment property, such an organic solvent causes disturbance in liquid crystal alignment and a decrease in pretilt angle.
• a liquid crystal alignment film having a pretilt-expressing group introduced into a polymer side chain has a problem that the control of the pretilt angle is easy, but the alignment of the liquid crystal is reduced. In particular, it was difficult to impart good liquid crystal orientation and a stable pretilt angle to a weak rubbing / washing with an organic solvent. Disclosure of the invention
• the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid crystal aligning agent for obtaining a liquid crystal alignment film capable of exhibiting a high and thermally stable pretilt angle. It is to be. It is a further object of the present invention to rely on process steps such as weak rubbing and cleaning with organic solvents. Another object of the present invention is to provide a liquid crystal alignment agent for obtaining a liquid crystal alignment film capable of exhibiting stable alignment and a pretilt angle.
• the present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, completed the present invention. That is, the present invention relates to the following.
• a liquid crystal aligning agent containing at least one polymer for forming a liquid crystal alignment film, wherein at least one of the polymers has an alkylene group having 4 to 16 carbon atoms in a main chain, and A liquid crystal aligning agent, which is a polymer having a side chain that increases the pretilt angle of the liquid crystal.
• liquid crystal aligning agent according to the above 1, wherein the side chain for increasing the pretilt angle of the liquid crystal is a monovalent organic group having an alkyl group or a fluoroalkyl group having 4 to 20 carbon atoms.
• liquid crystal aligning agent according to the above 1, wherein the side chain for increasing the pretilt angle of the liquid crystal has the structure shown in the following (1).
• X represents a single bond or a divalent linking group
• R represents an alkyl group having 4 to 20 carbon atoms, a fluoroalkyl group having 4 to 20 carbon atoms, a benzene ring or a cyclic hexane ring.
• a polymer having an alkylene group having 4 to 16 carbon atoms in the main chain and having a side chain that increases the pretilt angle of the liquid crystal has a repeating unit represented by the following general formula (5) 2.
• A represents a tetravalent organic group
• B represents a divalent organic group
• Y 2 represents a tetravalent organic group
• Y 3 represents a trivalent organic group
• X represents a single bond or a divalent bonding group
• R represents an alkyl group having 4 to 20 carbon atoms.
• the structure represented by the formula (6) is 20 to 95%, which is represented by the formula (7).
• the liquid crystal alignment agent of the present invention is a solution containing at least one polymer for forming a liquid crystal alignment film, wherein the polymer has an alkylene group having 4 to 16 carbon atoms in a main chain, and By using a polymer having a side chain that increases the pretilt angle of the liquid crystal, a liquid crystal alignment film that exhibits a high and stable pretilt angle can be obtained.
• that the polymer has an alkylene group having 4 to 16 carbon atoms in the main chain means that the polymer has 4 to 16 continuous methylene groups in the main chain.
• the hydrogen on the continuous methylene group may be substituted with a methyl group or an ethyl group.
• the side chain that increases the pretilt angle of the liquid crystal refers to a side chain that has an effect of increasing the pretilt angle of the liquid crystal by introducing the side chain.
• the side chains in the polymer may be of one type or of multiple types.
• the side chain for increasing the pretilt angle of the liquid crystal includes an alkyl group having 4 to 20 carbon atoms, a fluoroalkyl group having 4 to 20 carbon atoms, a group having 1 to 3 benzene rings or cyclohexan rings, and a steroid skeleton. And the like.
• alkyl groups and fluoroalkyl groups have carbon atoms Those having 8 to 20 carbon atoms are preferable, those having 1220 carbon atoms are more preferable, and those having 16 to 18 carbon atoms are particularly preferable.
• a group having 1 to 3 benzene rings or cyclohexane rings, or a group having a steroid skeleton is preferably a group having 1 to 16 carbon atoms in addition to these ring structures, more preferably Has an alkyl group having 4 to 8 carbon atoms.
• These organic groups forming a side chain may be directly bonded to the polymer main chain, or may be bonded via a divalent bonding group.
• the bonding group include ethers, esters, amides, iminos, groups in which these groups are combined with alkylene having 1 to 3 carbon atoms, and alkylenes having 1 to 3 carbon atoms.
• the side chain including such a bonding group is represented by the following formula (1).
• X represents a single bond or a divalent bonding group
• R represents an alkyl group having 4 to 20 carbon atoms, a fluoroalkyl group having 4 to 20 carbon atoms, a benzene ring or a cyclic hexane ring having 1 to 3 carbon atoms.
• at least one organic group selected from the group consisting of a group having a steroid skeleton and a group having a steroid skeleton.
• XI represents a single bond, one of 0—, —COO—, and R 1 represents an alkyl group having 8 to 20 carbon atoms.
• X2 represents a single bond, _ ⁇ —, —COO—, one CH 2 —, one CH 2 ⁇
• R2 represents one of the following formulas (4)
• X3 Represents a single bond, —O—, or one CO ⁇
• R 3 represents an alkyl group having 1 to 16 carbon atoms.
• the polymer for forming the liquid crystal alignment film includes polyamide, polyamic acid, polyimide, polyamideimide, polyurea, polyurethane, polyether, polyester ether ketone, polyester, polycarbonate, polysulfide, and polybutylene.
• Benzoimidazole, polybenzoxazole, polyesterimide, aramide and the like it is particularly preferable to use polyamic acid or polyimide because of its excellent reliability when used as a liquid crystal alignment film.
• a polyamic acid having an alkylene group having 4 to 16 carbon atoms in the main chain and having a side chain that increases the pretilt angle of the liquid crystal can be obtained by reacting a diamine component with a tetracarboxylic acid dianhydride component. Can be done. Specifically, (a) diamine having an alkylene having 4 to 16 carbon atoms in a main skeleton is used as one of the diamine components, and liquid crystal pretilt is used as one of the tetracarboxylic dianhydride components. (B) using one of diamines having a side chain to increase the pretilt angle of a liquid crystal as one of the diamine components, wherein the tetracarboxylic acid dianhydride is used.
• a method using tetracarbonic dianhydride having an alkylene having 4 to 16 carbon atoms in the main skeleton (c) in the diamine component, A method in which a diamine having an alkylene having 4 to 16 carbon atoms and a diamine having a side chain that increases the pretilt angle of a liquid crystal are used in combination.
• the main skeleton has a carbon number of A method in which a tetracarboxylic dianhydride having 4 to 16 alkylenes is used in combination with a tetracarboxylic dianhydride having a side chain that increases the pretilt angle of the liquid crystal.
• This polyamic acid can be represented as a polyamic acid having a repeating unit represented by the following general formula (5).
• A represents a tetravalent organic group
• B represents a divalent organic group
• a diamine compound having an alkylene having 4 to 16 carbon atoms in the main skeleton are preferable, and in particular, a diamine compound having a side chain that increases the pretilt angle of a liquid crystal is preferably used in combination. What is obtained by is preferred.
• a polyimide having an alkylene group having 4 to 16 carbon atoms in the main chain and having a side chain that increases the pretilt angle of the liquid crystal can be obtained by dehydrating and ring-closing the above polyamic acid.
• diamine compounds having an alkylene having 4 to 16 carbon atoms in the main skeleton include 1,4-bis (4-aminophenoxy) butane and 1,5-bis (4- Aminophenoxy) pentane, 1,6-bis (4-aminophenoxy) hexane, 1,7-bis (4-aminophenoxy) heptane, 1,8-bis (4-aminophenoxy) octane, 1,9-bis (4- Aminophenoxy) Nonane, 1,10-bis (4-7 minophenoxy) decane, 1,1 1-bis (4-aminophenoxy) pentane, 1,12-bis (4-aminophenoxy) dodecane, 1,1 3 — Bis (4-aminophenoxy) tridecane, 1,14-bis (4-aminophenoxy) tetradecane, 1,15-bis (4-aminophenoxy) ⁇ Decane and 1,16-bis (4-aminophenoxy) hexadecane.
• aliphatic diamines examples include 1,4 diaminobutane, 1,5-diaminopentane, 1,6 diaminohexane, 1,7 diaminoheptane, 1,8 diaminooctane, 1,9-diaminononane, 1, 10-Diaminodecane, 1,6-Diamino-2,5-dimethylhexane, 1,7-Diamino_2,5-dimethylheptane, 1,7-Diamino1.4,4-dimethylheptane, 1,7-Diamino 3 —Methylheptane, 1,9 diamino-5-methylnonane, 2,11 diaminododecane, 1,12 diaminooctadecane, 1,2-bis (3-aminopropoxy) ester, etc.
• polyamic acids obtained from these diamine compounds as raw materials polyamic acids having a structure represented by the following formula (6) in the main chain are preferable.
• Such a polyamic acid can be obtained by using the above-mentioned aromatic diamine compound.
• Y 1 represents a tetravalent organic group
• k represents an integer of 4 to 16.
• a polyamic acid having a structure represented by the above formula (6) or a polyimide obtained by dehydrating and ring-closing this polyamic acid is preferable.
• a polymer using 1,5-bis (4-aminophenoxy) pentane, that is, k of the formula (6) is excellent because of its excellent liquid crystal orientation and heat resistance of the pretilt angle when a liquid crystal alignment film is formed. Is particularly preferably 5.
• the diamine compound having a side chain that increases the pretilt angle of the liquid crystal is a diamine in which the above-described side chain that increases the pretilt angle of the liquid crystal is bonded to a diamine main skeleton having two primary amino groups.
• the side chain of diamine include the structure of the above formula (1), and preferable side chains include those represented by the above formula (2) or (3).
• X 1 is preferably —0_, and R 1 is preferably an alkyl group having 12 to 18 carbon atoms.
• X 2 is any one of —0— and CH 2 0—, R 2 is the above 4 b, X 3 is a single bond, and R 3 is an alkyl group having 4 to 12 carbon atoms. Particularly preferred.
• diaminobenzene diaminobiphenyl, diaminodiphenyl ether, diaminodiphenylmethane, diaminodiphenylamine, and the like are preferable from the viewpoint of the efficiency of increasing the pretilt angle.
• a diaminobenzene skeleton is particularly preferred.
• diamine compound as described above examples include 41- (dodecyloxy) -1,3-diaminobenzene, 4- (hexadecyloxy) 1-1,3-diaminobenzene, and 41- (octadecyloxy). 1), 3-Diaminobenzene, 4- [4- (4-Heptylcyclohexyl) phenoxy] 1-1,3-Diaminobenzene, and 5- ⁇ [4- (4-Heptylcyclo to mouth Xyl) phenoxy] methyl ⁇ —1,3-diaminobenzene. Needless to say, these diamine compounds as pretilt angle developing components can be used alone or in combination.
• polyamic acids obtained from a diamine compound having a side chain that increases the pretilt angle of the liquid crystal are polyamic acids having a structure represented by the following formula (7) in the main chain. That is, in the repeating unit represented by the general formula (5), a polyamic acid containing a structure represented by the following formula (7) as one of the repeating structures or a dehydration-cyclization of the polyamic acid is included. Polyimides are preferred.
• Y 2 represents a tetravalent organic group
• ⁇ 3 represents a trivalent organic group
• X and R are the same as defined in the above formula (1).
• ⁇ 3 is preferably a skeleton selected from benzene, biphenyl, diphenylether, diphenylethane, diphenylmethane, and diphenylamine, and a benzene skeleton is more preferable.
• a diamine component for polymerizing the polyamic acid used in the present invention a diamine compound having an alkylene having 4 to 16 carbon atoms in a main skeleton and a diamine compound having a side chain that increases a pretilt angle of a liquid crystal are further added. And a typical diamine compound. Specific examples of the additional diamine compound are shown below.
• Examples of alicyclic diamines are 1,4-diaminocyclohexane, 1,3 diaminocyclohexane, 4,4, diaminodicyclohexylmethane, 4,4 'diamino-3,3'-dimethyldicyclohexylamine , And isophorone diamine.
• Examples of carbocyclic aromatic diamines include ⁇ -phenylenediamine, m-phenylenediamine, p-phenylenediamine, diaminotoluenes (for example, 2,4 diaminotoluene), and 1,4-diamino-2-methoxybenzene.
• the polyamic acid having the structural unit represented by the general formula (5) can be obtained by reacting the diamine component with the tetracarboxylic dianhydride as described above.
• the structure represented by the formula (6) is preferably 20 to 95%, more preferably 50 to 95 mol%, more preferably 70 to 95%, of the structural units represented by the general formula (5). % Is particularly preferred.
• the structure represented by the formula (7) is preferably 5 to 30% of the structural unit represented by the general formula (5), and is 5 to 20% depending on the desired pretilt angle. % Or 5 to 10%.
• the tetracarboxylic dianhydride to be reacted with the diamine component as described above is not particularly limited.
• Specific examples of the aromatic acid dianhydride include pyromellitic dianhydride, 3,3 ', 4,4'-biphenyletratetracarboxylic dianhydride, 2,2,3,3 '—Biphenyltetracarboxylic dianhydride, 2,3,3,, 4'-Biphenyltetracarboxylic dianhydride, 3,3,, 4,4'-Benzophenonetetracarboxylic dianhydride , 2,3,3 '., 4,1-Benzophenonetetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride , 1,2,5,6-acid dianhydride, 2,3,6,7-naphthalenetetraacid dianhydride and the
• Xycyclopentylacetic acid dianhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalenesuccinic dianhydride, and the like are exemplified. Naturally, these acid dianhydrides can be used alone or in combination.
• Y1 in the above formula (6) or Y2 in the formula (7) is represented by the following formula (8)
• Such a polyamic acid can be obtained by using 1,2,3,4-cyclobutanetetracarboxylic dianhydride as the acid dianhydride.
• the polyamic acid used in the present invention is obtained by treating the above-mentioned diamine and acid dianhydride in the presence of an organic solvent at a temperature of from 120 to 150 ° C, preferably from 0 to 80 ° C, for 30 minutes to 24 hours.
• the reaction can be carried out preferably by reacting for 1 to 10 hours.
• the solvent used in the polymerization reaction is not particularly limited, but N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, dimethylsulfoxide, tetramethylurea It is preferable to use pyridine, and ptyrrolactone because the resulting polyamic acid has high solubility.
• the concentration of the solution during the polymerization reaction is too high, the handleability of the resulting polyamic acid solution will be poor, and if it is too low, the molecular weight will not increase, so it is preferably 1 to 50% by weight, more preferably 5 to 30% by weight. %, Particularly preferably 8 to 20% by weight. Needless to say, a poor solvent such as butyl cellosolve toluene or methanol may be added as long as the polymer is dissolved.
• the molecular weight of the polyamic acid can be reduced by subjecting the reaction system to a nitrogen atmosphere or performing the reaction while bubbling nitrogen through the solvent in the reaction system Is preferred because of easy rise.
• a method in which imidization proceeds by heating a method in which imidization is chemically performed using a catalyst, and the like can be exemplified.
• a polyimide obtained by chemically imidizing with a catalyst because the reaction easily proceeds and a side reaction hardly occurs.
• Chemical imidization is carried out by adding a base catalyst in an amount of 2 to 20 mol times of an acid of an acid and an acid anhydride in an amount of 3 to 30 times of an acid of an amic acid to a solution of a polyamic acid.
• the reaction is preferably performed at a temperature of C, preferably 0 to 250 T: for 1 to 100 hours.
• the reaction does not proceed sufficiently, and if the amount is too large, it is difficult to completely remove the base catalyst or the acid anhydride after the completion of the reaction.
• the base catalyst include pyridine, triethylamine, trimethylamine, triptylamine, trioctylamine, and the like. Among them, pyridine is preferable because it has an appropriate basicity for the reaction to proceed.
• the acid anhydride include acetic anhydride, trimellitic anhydride, and pyromellitic anhydride. Among them, acetic anhydride is preferred because purification after the reaction is easy.
• the polymer component can be precipitated and recovered by injecting the polyamic acid or polyimide solution into a poor solvent.
• a catalyst when used during polymer synthesis, when unreacted monomers remain in the solution, and when the solvent used for polymer synthesis is not suitable as a component of the liquid crystal aligning agent, the polymer is recovered. Therefore, it is preferable to use it for a liquid crystal aligning agent.
• the poor solvent used for recovering the polymer by precipitation is not particularly limited, but examples thereof include methanol, acetate, hexane, butylcellosolve, heptane, methylethylketone, methylisobutylketone, ethanol, toluene, and benzene.
• the polymer obtained by precipitation can be recovered by filtration and then dried at normal temperature or under reduced pressure at normal temperature or under reduced pressure to obtain a powder. It is preferable that the operation of further dissolving the powder in a good solvent and reprecipitating is repeated 2 to 10 times, because the impurities in the polymer are reduced and the electrical characteristics of the liquid crystal alignment film are excellent.
• poor solvents include alcohols and ketones. It is preferable to use three or more kinds of poor solvents such as hydrocarbons because the purification efficiency is further improved.
• a method of copolymerizing a monomer having an alkylene group having 4 to 16 carbon atoms in the main chain with a monomer having a side chain that increases the pretilt angle of the liquid crystal To a polymer having an alkylene group having 4 to 16 carbon atoms and a side chain that increases the pretilt angle of the liquid crystal.
• the reduced viscosity of the polymer for forming the liquid crystal alignment film is not particularly limited as long as a uniform coating film can be formed, but is preferably from 0.05 to 3.0 O dl / g. Preferably, 0.1 to 2.5 dl / g is more preferred, and 0.3 to 1.5 d1Zg is particularly preferred. If the reduced viscosity of the polymer is too high, it becomes difficult to handle the liquid crystal aligning agent, and if it is too low, the characteristics of the liquid crystal aligning film may not be stable.
• the polymer having an alkylene group having 4 to 16 carbon atoms in the main chain and having a side chain that increases the pretilt angle of the liquid crystal obtained as described above has a concentration suitable for application to a substrate.
• the solution is used as the liquid crystal aligning agent of the present invention.
• the polymer component contained in the liquid crystal alignment agent may be one type, or two or more types may be mixed.
• two or more polymers are contained in the liquid crystal aligning agent, at least one of them has an alkylene group having 4 to 16 carbon atoms in the main chain and increases the pretilt angle of the liquid crystal. Any polymer having a chain may be used.
• the solvent used for the liquid crystal aligning agent of the present invention is not particularly limited as long as it can dissolve the contained components uniformly.
• examples include good solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, dimethylsulfoxide, tetramethylurea, pyridine, and butyrolactones. Is mentioned. Above all, it is preferable to include an amide-based solvent because the solubility of the polymer is high. Particularly, when N-methyl-12-pyrrolidone or N, N-dimethylacetoamide is included, printability of the liquid crystal aligning agent is improved. It is preferred.
• Alkylene diol monoalkyl ethers such as Solve TM propylene propylene glycol monobutyl ether; dialkylene glycol monoalkyl ethers such as ethyl carbitol dipropylene glycol—methyl monomethyl ether; dialky such as diglyme and diethylene glycol dimethyl ether
• Polymers such as lenglycol dialkyl ethers, alkyl lactates such as butyl lactate, and alcohols such as methyl alcohol are low in polymer solubility, but are included in the liquid crystal aligning agent for printing. It is preferable to mix these poor solvents as long as the polymer component does not precipitate, since it has the effect of improving the uniformity and smoothness of the coating film. Specifically, it is preferable to use a solvent containing 30 to 99.9% by weight of a good solvent and 0.1 to 70% by weight of the poor solvent.
• the resin concentration is preferably 0.1 to 30% by weight, more preferably 1 to 10% by weight.
• the coupling agent refers to a compound having a covalent bond between an oxygen atom and at least one element selected from silicon and all typical metal elements belonging to groups 1 to 3 and all transition metal elements. Show. Among them, coupling agents having an alkoxysilane, alkoxyaluminum, alkoxyzirconium, or alkoxytitanium structure are preferred because they are easily available and are excellent in cost.
• 3-aminopropyltrimethoxysilane is particularly preferable because the electrical characteristics of a liquid crystal display device are improved.
• the amount of the coupling agent is large, the strength of the alignment film is weakened, and when the amount is small, the effect of improving the adhesion is reduced. Therefore, 0.01 to 30% by weight of the solid content in the liquid crystal alignment agent is more preferable. It is 0.1 to 20% by weight, particularly preferably 0.5 to 10% by weight.
• the solvent and the concentration for diluting the coupling agent are not particularly limited.
• N-methyl-12-pyrrolidone, dimethylacetamide, dimethylformamide, toluene, hexane, heptylolactone, etc. using a solvent used in the polymer solution, 1 to 50% by weight, preferably It is preferable to use after diluting to a concentration of 3 to 30% by weight.
• the liquid crystal alignment agent of the present invention can be formed into a liquid crystal alignment film by forming a coating film on a substrate after filtration and rubbing.
• the substrate to be used is not particularly limited, and a glass substrate, an acrylic substrate, or a plastic substrate such as a polyacrylonitrile substrate can be used. Needless to say, it is preferable to use a substrate on which an IT0 electrode or the like for driving the liquid crystal is formed from the viewpoint of simplifying the process.
• the liquid crystal aligning agent can be applied by a method such as a spin coating method, a printing method, and an inkjet method.
• the coating is formed by applying a liquid crystal aligning agent and then drying at a temperature of 50 to 300 ° C, preferably 80 to 250 ° C for 1 to 100 minutes.
• the thickness of the film to be formed is 5 to 300 ⁇ , more preferably 7 to 100 nm, and particularly preferably 7 to 100 nm, because if it is too thick, it is disadvantageous in cost, and if it is too thin, the reliability of the liquid crystal display element decreases. Is preferably 10 to 8 O nm.
• Rubbing of the coating film is performed by rubbing the film surface in one direction using a cloth such as nylon, rayon, or cotton.
• the pushing amount of the rubbing cloth is 0.11 to 11M, more preferably 0.1 to 0.7 thigh, but the pushing amount of the rubbing cloth is preferably smaller because the generation of dust is suppressed. .
• the rubbed substrate with a liquid crystal alignment film is preferably washed with water, methanol, ethanol, isopanol, or the like to remove dust generated during rubbing.
• the cleaning method is to immerse the substrate in the above liquid, It is preferable that dust is removed efficiently by applying water.
• the washing solution is preferably water, isopropanol, or a mixed solution of water and isopropanol. In particular, it is preferable to perform ultrasonic cleaning with a cleaning solution containing isopropanol for 1 minute or more.
• the substrate with a liquid crystal alignment film thus obtained can be used for manufacturing a liquid crystal display element after the cleaning liquid is dried.
• a solution of polyamic acid (a-1) is diluted with NMP and butyl sorbate (hereinafter abbreviated as BCS) to obtain a polyamic acid concentration of 5% by weight and a BCS concentration of 20% by weight. Obtained.
• the substrate with a liquid crystal alignment film was washed in water for 1 minute by applying ultrasonic waves, water drops were blown off with an air gun, and further dried at 80 ° C for 10 minutes.
• This substrate is assembled into a pair, and the liquid crystal (Merck MLC-2003) is injected with a 50 xm spacer sandwiched between them so that the alignment film surface is inside and the rubbing direction is antiparallel.
• a liquid crystal cell was prepared. Observation of the alignment state of the liquid crystal cell with a polarizing microscope confirmed that the liquid crystal cell was uniformly aligned without defects.
• the pretilt angle of the liquid crystal was measured by a crystal rotation method.
• the pretilt angle was measured without heat treatment after liquid crystal injection, and then heat aging treatment was performed at 105 ° C for 5 minutes and 12060 minutes, and the pretilt angle after each heat treatment was measured at room temperature. did.
• the order was 4.8 degrees, 4.6 degrees, and 4.7 degrees, and each condition had a high pretilt angle. And no change in the pretilt angle with respect to the heat treatment was observed.
• the solution of the polyamic acid (a-2) was diluted with NMP and BCS to obtain a polyamic acid concentration of 5% by weight and a BCS concentration of 20% by weight. Agent was obtained.
• the pretilt angle was evaluated in the same manner as in the liquid crystal aligning agent of Example 1.
• the pretilt angles of the liquid crystal were 3.8 degrees, 3.9 degrees, and 4.2 degrees before heat treatment, after 105 ° C / 5 minutes, and after 120 ° C / 60 minutes, respectively. It had a high pretilt angle and hardly changed the pretilt angle with respect to the heat treatment.
• a solution of the polyamic acid (a-3) was diluted with NMP and BCS to obtain a polyamic acid concentration of 5% by weight and a BCS concentration of 20% by weight to obtain a liquid crystal aligning agent for comparison.
• the pretilt angle was evaluated in the same manner as in the liquid crystal aligning agent of Example 1.
• the pretilt angles of the liquid crystal were 6.3 degrees, 6.0 degrees, and 5.6 degrees before heat treatment, after 105 minutes at 105 ° C, and after 60 minutes at 120. Although the angle was shown, a decrease in the pretilt angle with respect to the heat treatment was observed.
• the pretilt angle was evaluated in the same manner as in the liquid crystal aligning agent of Example 1.
• the pretilt angle of the liquid crystal before the heat treatment 10 5 D C / 5 minutes after, in the order after 1 20 ° C / 60 min, 5.6 °, 5.4 °, a 5.0 degrees, each Although the pretilt angle was high under all the conditions, the pretilt angle decreased with respect to the heat treatment.
• the polyamic acid (a-5) solution was diluted with NMP and BCS to obtain a polyamic acid concentration of 5% by weight and a BCS concentration of 20% by weight to obtain a liquid crystal aligning agent of the present invention.
• the pretilt angle was evaluated in the same manner as in the liquid crystal aligning agent of Example 1.
• the pretilt angles of the liquid crystal were 8.9 degrees, 8.8 degrees, and 8.9 degrees before heat treatment, after 105 minutes at 105 ° C, and after 120 minutes / 60 minutes, respectively. Both had a high pretilt angle, and almost no change in the pretilt angle with respect to the heat treatment was observed.
• the solution of the polyamic acid (a-6) was diluted with NMP and BCS to obtain a polyamic acid concentration of 5% by weight and a BCS concentration of 20% by weight to obtain a liquid crystal aligning agent of the present invention.
• the pretilt angle was evaluated in the same manner as in the liquid crystal aligning agent of Example 1.
• the pretilt angles of the liquid crystal were 6.9 degrees, 6.8 degrees, and 7.2 degrees before heat treatment, after 105 ° C / 5 minutes, and after 120 ° C / 60 minutes, respectively. In both cases, the pretilt angle was high, and the pretilt angle was hardly changed by the heat treatment.
• 1,47-bis (4-aminophenoxy) pentane 7.47 g (26.09 mmo 1), 5- ⁇ [4- (4-hexylhexylhexyl) phenoxy] methyl ⁇ —1,3— 1.14 g (2.89 mmo 1) of diaminobenzene was dissolved in 98 g of NMP. To this was added 6.14 g (28.15 mmo 1) of pyromellitic dianhydride and reacted at room temperature for 4 hours. The reduced viscosity was about 1.ldl / g (concentration 5 g / dl, in NMP). (Measured with 3 O)).
• the solution of the polyamic acid (a-7) was diluted with NMP and BCS to obtain a polyamic acid concentration of 5% by weight and a BCS concentration of 20% by weight to obtain a liquid crystal aligning agent of the present invention.
• the pretilt angle was evaluated in the same manner as in the liquid crystal aligning agent of Example 1.
• the pretilt angles of the liquid crystal were 8.3 degrees, 8.0 degrees, and 8.2 degrees before heat treatment, after 105 ° C / 5 minutes, and after 120 ° C / 60 minutes, respectively. In both cases, the pretilt angle was high, and the pretilt angle was hardly changed by the heat treatment.
• 3-Aminopropyltrimethoxysilane (LS-3150: Shin-Etsu Chemical Co., Ltd.) diluted to 2% with N, N-dimethylacetamide was added to a solution of polyamic acid (a-8).
• Minopropyltrimethoxysilane was added so as to be 1% by weight based on the polyamic acid, and further diluted with a lactone lactone to obtain a solution having a polyamic acid concentration of 5% by weight.
• the pretilt angle was evaluated in the same manner as in the liquid crystal aligning agent of Example 1.
• the pretilt angles of the liquid crystal were 4.0 degrees, 4.1 degrees, and 4.3 degrees before heat treatment, after 5 minutes at 105 ° C ZZ, and after 60 minutes at 120 ° C ZZ.
• the pre-tilt angle was hardly changed by the heat treatment.
• the liquid crystal aligning agent obtained in Example 1 was filtered through a 0.5-fill filter, and then spin-coated on a glass substrate with a transparent electrode, and baked at 200/30 minutes to obtain a coating film having a thickness of 7 Onm. did. Furthermore, this coating film was rubbed with a rayon cloth with a bristle length of 2 and a push-in amount of 0.3, a roller rotation speed of 300 rpm, and a roller feed speed of 4 Omm / s. It was a membrane.
• the substrate with a liquid crystal alignment film was washed in isopropanol for 1 minute by applying ultrasonic waves, and then the droplets were blown off with an air gun, followed by drying at 80 for 10 minutes.
• This board is a set of two, and a 50 m spacer A liquid crystal (MLC-203, manufactured by Merck) was injected to assemble the liquid crystal cell so that the alignment film surface was inside and the rubbing direction was antiparallel, and a liquid crystal cell was formed.
• the pretilt angle of the liquid crystal measured by the crystal rotation method was 9.9 degrees. Observation of the alignment state of this liquid crystal cell with a polarizing microscope confirmed that the liquid crystal cell was uniformly aligned without defects, and despite good rubbing conditions and washing with an organic solvent, good alignment and high pretilt. Had a corner.
• Example 7 The same evaluation as in Example 7 was performed using the liquid crystal aligning agent obtained in Example 2. As a result, the pretilt angle of the liquid crystal was 8.7 degrees, and it was confirmed that the liquid crystal had a uniform alignment without defects. The liquid crystal had good alignment despite weak rubbing conditions and washing with an organic solvent. And a high pretilt angle.
• Example 7 The same evaluation as in Example 7 was performed using the liquid crystal aligning agent obtained in Example 3. As a result, the pretilt angle of the liquid crystal was 8.7 degrees, and it was confirmed that the liquid crystal had a uniform alignment without defects. The liquid crystal had good alignment despite weak rubbing conditions and washing with an organic solvent. And a high pretilt angle.
• Example 7 The same evaluation as in Example 7 was performed using the liquid crystal aligning agent obtained in Example 4. As a result, the pre-tilt angle of the liquid crystal was 7.3 degrees, and it was confirmed that the liquid crystal had a uniform alignment without any defects. The liquid crystal had good alignment despite weak rubbing conditions and washing with an organic solvent. And a high pretilt angle. Industrial applicability
• the liquid crystal display device manufactured using the liquid crystal alignment agent of the present invention exhibits a high pretilt angle, does not cause a decrease in the pretilt angle when the display device is thermally aged, and has a high reliability. It can be. Further, the liquid crystal alignment film produced using the liquid crystal alignment agent of the present invention has a weak rubbing condition. Despite the fact that it is washed with an organic solvent such as isopropanol, it has good orientation and a high pretilt angle.

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