Classifications

• • 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
• • 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
• • 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

Definitions

• the present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display device using the same.
• a polyimide resin film is widely used as a liquid crystal alignment film used for liquid crystal display devices.
• This polyimide-based liquid crystal alignment film is produced by applying a liquid crystal alignment agent containing a polymer such as polyamic acid (also referred to as polyamic acid), polyamic acid ester, or polyimide and a solvent as main components to a substrate.
• a liquid crystal alignment agent containing a polymer such as polyamic acid (also referred to as polyamic acid), polyamic acid ester, or polyimide and a solvent as main components.
• liquid crystal display elements have been improved in performance and area, power consumption of display devices has been reduced, and liquid crystal display elements have come to be used in various environments. Problems have become noticeable. For example, static electricity is easily accumulated in the liquid crystal cell, and charges accumulated in the liquid crystal alignment film affect the display as disturbance of the liquid crystal alignment or an afterimage, which significantly deteriorates the display quality of the liquid crystal display element. In addition, when a liquid crystal panel is driven for a long period of time, the magnitude of flicker (flicker) changes due to the application of positive and negative asymmetric voltages due to the accumulation of electric charges generated by the driving.
• flicker flicker
• Patent Documents 1 to 4 describe liquid crystal aligning agents containing a polyamic acid obtained from a low resistance material such as 4,4′-diaminodiphenylamine (DADPA).
• DADPA 4,4′-diaminodiphenylamine
• the DC luminance relaxation rate is increased, but the change in flicker may be large.
• the DC luminance relaxation rate may be slowed down. That is, in the conventional liquid crystal alignment film, there is a trade-off relationship between the speed of the DC luminance relaxation rate and the suppression of the change in flicker, and there is a case where both are not provided, which is a problem.
• the transmittance of the substrate may decrease due to coloring, which has been a problem.
• a liquid crystal aligning agent comprising the following polymer (A), polymer (B) and polymer (C).
• a 1 is a single bond, an ether bond, an ester bond, —C ⁇ C—, —C ⁇ C—, an alkylene group having 2 to 20 carbon atoms, or an alkylene group in the alkylene group.
• a 2 is a fluorine atom, or an alkyl group or an alkoxy group having 1 to 5 carbon atoms (provided that any hydrogen atom of the alkyl group or the alkoxy group is substituted with a fluorine atom).
• A is an integer of 0 to 4, and when a is an integer of 2 or more, A 2 may be the same or different, and b and c are each independently 1 to 2 Is an integer of );
• liquid crystal aligning agent of the present invention it is possible to obtain a liquid crystal aligning film having both a fast DC luminance relaxation rate and suppression of flicker change. Further, according to the liquid crystal aligning agent of the present invention, it is possible to obtain a liquid crystal aligning film having a high substrate transmittance even when a low resistance material is used.
• the polymer (A) contained in the liquid crystal aligning agent of the present invention is the following polymer.
• a polyamic acid obtained by polymerizing a tetracarboxylic acid component of (Ii) A diamine component containing at least one diamine selected from the group consisting of the diamine represented by the following formula [1] and the diamine represented by the formula [2] is polymerized with a tetracarboxylic acid component. The polyamic acid ester thus obtained.
• a diamine component containing at least one diamine selected from the group consisting of a diamine represented by the following formula [1] and a diamine represented by the formula [2] is polymerized with a tetracarboxylic acid component.
• a polyimide obtained by imidizing the obtained polyimide precursor is a polyimide precursor.
• a 1 is a single bond, an ether bond, an ester bond, —C ⁇ C—, —C ⁇ C—, an alkylene group having 2 to 20 carbon atoms, or an alkylene group in the alkylene group.
• a 2 is a fluorine atom, or an alkyl group or an alkoxy group having 1 to 5 carbon atoms (provided that any hydrogen atom of the alkyl group or the alkoxy group is substituted with a fluorine atom).
• A is an integer of 0 to 4, and when a is an integer of 2 or more, A 2 may be the same or different, and b and c are each independently 1 to 2 Is an integer.
• the diamine component for producing the polymer (A) contains at least one diamine selected from the group consisting of the diamine represented by the above formula [1] and the diamine represented by the above formula [2]. is there.
• a 1 is a single bond, —C ⁇ C—, —C ⁇ C—, an alkylene group having 2 to 10 carbon atoms, or —CH 2 — in the alkylene group.
• Examples of the diamine represented by the formula [1] to the formula [2] include the following.
• the amount of the diamine represented by the formulas [1] and [2] used is 30 to 100 mol %, more preferably 40 to 100 mol% based on the total amount of the diamine component for producing the polymer (A). Mol%, and more preferably 50 to 100 mol%.
• any diamine other than the diamines represented by the formulas [1] and [2] hereinafter, referred to as “other Also referred to as "diamine”.
• diamines include 4,4′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, 4, 4'-diaminobenzophenone, 4,4'-diaminoazobenzene, 1-(4-aminophenyl)-1,3,3-trimethyl-1H-indan-5-amine, 1-(4-aminophenyl)-2, 3-dihydro-1,3,3-trimethyl-1H-inden-6-amine, 1,4-diaminonaphthalene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,7-diaminonaphthalene, 2, 2'-bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-bis[4-(4-aminophenoxy)
• X v1 to X v4 and X p1 to X p8 are each independently -(CH 2 ) a- (a is an integer of 1 to 15). .), —CONH—, —NHCO—, —CON(CH 3 )—, —NH—, —O—, —CH 2 O—, —CH 2 OCO—, —COO—, or —OCO—, X v5 represents —O—, —CH 2 O—, —CH 2 OCO—, —COO—, or —OCO—, and Xa represents a single bond, —O—, —NH—, —O—(CH 2 ) m -O- (m is an integer of 1-6.) indicates, R v1 ⁇ R v4, R 1a ⁇ R 1b are each independently an alkyl group of 1 to 20 carbon atoms, a C1- 20 alkoxy groups or
• the diamine component for producing the polymer (A) of the present invention includes the solubility of the polymer (A) in a solvent, the coatability of a liquid crystal aligning agent, the liquid crystal aligning property when used as a liquid crystal aligning film, and the voltage holding ratio. It is also possible to use one kind or a mixture of two or more kinds according to the characteristics such as accumulated charge.
• the tetracarboxylic acid component for producing the (i) polyamic acid of the polymer (A) consists of an aromatic tetracarboxylic dianhydride.
• the aromatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups bonded to the same or different aromatic rings. In this case, if the number of aromatic rings is one, an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups bonded to the aromatic ring is preferable.
• an acid obtained by intramolecular dehydration of two carboxyl groups bonded to one aromatic ring and intramolecular dehydration of two carboxyl groups bonded to another aromatic ring A dianhydride, or a carboxyl group bonded to one of two adjacent aromatic rings and a carboxyl group bonded to the other are intramolecularly dehydrated, and a carboxyl group bonded to one of two adjacent aromatic rings and the other.
• An acid dianhydride obtained by intramolecular dehydration of the carboxyl group bound to is preferred.
• aromatic tetracarboxylic dianhydrides examples include compounds represented by the following formula (3a-1).
• X 1 is one of the following formulas (A-1) to (A-28). * Represents a bond.
• any tetracarboxylic dianhydride or its derivative tetracarboxylic acid, tetracarboxylic acid dihalide
• Tetracarboxylic acid dialkyl ester Tetracarboxylic acid dialkyl ester dihalide
• the tetracarboxylic acid component for producing the (ii) polyamic acid ester of the polymer (A) or the (iii) polyimide is preferably an aromatic tetracarboxylic dianhydride, an alicyclic tetracarboxylic dianhydride, or It is composed of an aliphatic tetracarboxylic dianhydride or a derivative thereof.
• aromatic tetracarboxylic dianhydride include those described above, and the alicyclic tetracarboxylic dianhydride or the aliphatic tetracarboxylic dianhydride is the alicyclic tetracarboxylic dianhydride in the polymer (C).
• An acid dianhydride or an aliphatic tetracarboxylic acid dianhydride is mentioned.
• Specific preferred examples of the aromatic tetracarboxylic dianhydride for producing the (ii) polyamic acid ester of the polymer (A) or the (iii) polyimide include compounds represented by the above formula (3a-1).
• Preferred examples of the alicyclic tetracarboxylic acid dianhydride or the aliphatic tetracarboxylic acid dianhydride include compounds represented by the following formula (3c-1).
• the tetracarboxylic acid component for producing the polymer (A) of the present invention includes the solubility of the polymer (A) in a solvent, the coatability of a liquid crystal aligning agent, the liquid crystal aligning property when used as a liquid crystal aligning film, and the voltage.
• a liquid crystal aligning agent the liquid crystal aligning property when used as a liquid crystal aligning film
• the voltage the voltage.
• One kind or a mixture of two or more kinds may be used depending on characteristics such as retention rate and accumulated charge.
• Polymer (B) contained in the liquid crystal aligning agent of the present invention is the following polymer.
• aromatic ring group means an n-valent group obtained by removing n hydrogen atoms from an aromatic ring
• specific examples of the aromatic ring include benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, and pyrene. Examples thereof include a ring, a perylene ring, and a terylene ring.
• Specific examples of the 5-membered or 6-membered nitrogen-containing aromatic heterocycle include a pyrrole ring and a pyridine ring.
• aromatic hydrocarbon ring include a benzene ring and a naphthalene ring.
• the diamine represented by the formula [3] preferably has a structure represented by the following formulas [3-1] to [3-3]. (In the formula, * represents a bond. However, in the formula [3-3], an aromatic hydrocarbon ring is bonded to at least one bond from the carbon atoms constituting the nitrogen-containing aromatic heterocycle. )
• the amount of the diamine represented by the formula [3] used is 30 to 100 mol %, more preferably 40 to 100 mol %, and further preferably 40 to 100 mol %, based on the total amount of the diamine component for producing the polymer (B). It is preferably 50 to 100 mol %.
• the diamine component for producing the polymer (B) contained in the liquid crystal aligning agent of the present invention any diamine other than the diamine represented by the formula [3], for example, the other diamine can be used. ..
• the diamine component for producing the polymer (B) of the present invention includes the solubility of the polymer (B) in a solvent, the coatability of a liquid crystal aligning agent, the liquid crystal aligning property when used as a liquid crystal aligning film, and the voltage holding ratio. It is also possible to use one kind or a mixture of two or more kinds according to the characteristics such as accumulated charge.
• any tetracarboxylic dianhydride or its derivative can be used as the tetracarboxylic acid component for producing the polymer (B) contained in the liquid crystal aligning agent of the present invention. More preferable specific examples of the tetracarboxylic dianhydride for producing the polymer (B) include aromatic tetracarboxylic dianhydride and alicyclic tetracarboxylic acid for producing the polymer (A). Examples thereof include dianhydride or aliphatic tetracarboxylic acid dianhydride.
• Preferred specific examples of the aromatic tetracarboxylic dianhydride include the compounds represented by the above formula (3a-1), and preferred are alicyclic tetracarboxylic dianhydride or aliphatic tetracarboxylic dianhydride. Specific examples include compounds represented by the following formula (3c-1).
• the tetracarboxylic acid component for producing the polymer (B) of the present invention includes the solubility of the polymer (B) in a solvent, the coatability of a liquid crystal aligning agent, the liquid crystal aligning property when used as a liquid crystal aligning film, the voltage. One kind or a mixture of two or more kinds may be used depending on characteristics such as retention rate and accumulated charge.
• the polymer (C) contained in the liquid crystal aligning agent of the present invention is the following polymer.
• the diamine component for producing the polymer (C) does not include the diamine represented by the formula [3].
• Examples of the diamine component for producing the polymer (C) include a diamine represented by the following formula [4]. (In the formula, Y is Has any one or more of the structures shown by, and * is a bond. )
• Y a divalent organic group having at least one partial structure shown above and at least one benzene ring is preferable.
• the diamine represented by the formula [4] include diamines represented by the following formulas (4-1) and (4-2).
• a 1 is a hydroxyl group, a carboxyl group, a fluorine atom, or an alkyl group or an alkoxy group having 1 to 5 carbon atoms (provided that any hydrogen atom of the alkyl group or the alkoxy group is substituted with a fluorine atom).
• At least one of A 1 represents a hydroxyl group or a carboxyl group
• a 2 represents a single bond, an ether bond, an ester bond, an alkylene group having 1 to 20 carbon atoms, or 1 to 20 carbon atoms.
• a divalent organic group in which a part of the alkylene group of is replaced by a urea bond or an amide bond, or a part or all of —CH 2 — in the divalent organic group is an ether bond, an ester bond, a cyclohexylene group.
• a group substituted with at least one group selected from the group consisting of a phenylene group a1 is an integer of 1 to 4, a21 and a22 are integers of 0 to 4, and a1, a21 or a22 is A 1 may be the same or different when they are integers greater than or equal to 2.
• a 2 represents a single bond or an alkylene group having 1 to 20 carbon atoms, either a21 or a22 is an integer other than 0.
• b and c are each independently an integer of 1 to 2.
• the diamine represented by the above formula [4] is preferably the following diamine, and particularly preferably is 1,3-bis(4-aminophenethyl)urea represented by the following formula.
• the diamine component for producing the polymer (C) of the present invention includes the solubility of the polymer (C) in a solvent, the coatability of a liquid crystal aligning agent, the liquid crystal aligning property when used as a liquid crystal aligning film, and the voltage holding ratio. It is also possible to use one kind or a mixture of two or more kinds according to the characteristics such as accumulated charge.
• the diamine component for producing the polymer (C) use any diamine other than the diamine represented by the formula [3] or the diamine represented by the formula [4], for example, the other diamine. You can
• the tetracarboxylic acid component for producing the polymer (C) is composed of an alicyclic tetracarboxylic dianhydride and/or an aliphatic tetracarboxylic dianhydride.
• the aliphatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups bonded to a chain hydrocarbon structure. However, it does not have to be composed only of a chain hydrocarbon structure, and a part thereof may have an alicyclic structure or an aromatic ring structure.
• the alicyclic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group bonded to the alicyclic structure. However, none of these four carboxyl groups is bonded to the aromatic ring. Further, it is not necessary to be composed only of an alicyclic structure, and a part thereof may have a chain hydrocarbon structure or an aromatic ring structure.
• Examples of the aliphatic tetracarboxylic dianhydride or the alicyclic tetracarboxylic dianhydride include compounds represented by the following formula (3c-1).
• X 2 is any one of the following formulas (B-1) to (B-18). * Represents a bond.
• the tetracarboxylic acid component for producing the polymer (C) of the present invention includes the solubility of the polymer (C) in a solvent, the coatability of a liquid crystal aligning agent, the liquid crystal aligning property when used as a liquid crystal aligning film, and the voltage.
• a liquid crystal aligning agent the liquid crystal aligning property when used as a liquid crystal aligning film
• the voltage the voltage.
• One kind or a mixture of two or more kinds may be used depending on characteristics such as retention rate and accumulated charge.
• the polyimide precursor that can be contained in the liquid crystal aligning agent of the present invention refers to polyamic acid or polyamic acid ester.
• the reaction between the diamine component and the tetracarboxylic acid component is usually performed in a solvent.
• the solvent used at that time is not particularly limited as long as it can dissolve the generated polyimide precursor. Specific examples of the solvent used in the reaction are shown below, but the solvent is not limited to these examples.
• N-methyl-2-pyrrolidone N-ethyl-2-pyrrolidone, ⁇ -butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, 3-methoxy-N,N-dimethylpropanamide, 3- Examples include butoxy-N,N-dimethylpropanamide, dimethyl sulfoxide, or 1,3-dimethyl-imidazolidinone.
• methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone or ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, diethylene glycol monomethyl ether, Diethylene glycol monoethyl ether and propyl ether such as diethylene glycol can be used.
• solvents may be used alone or as a mixture. Furthermore, even a solvent that does not dissolve the polyimide precursor may be used as a mixture with the solvent as long as the generated polyimide precursor does not precipitate. Further, since water in the solvent inhibits the polymerization reaction and causes hydrolysis of the generated polyimide precursor, it is preferable to use a dehydrated and dried solvent.
• the solution in which the diamine component is dispersed or dissolved in the solvent is stirred, and the tetracarboxylic acid component is added as it is or in the solvent after being dispersed or dissolved.
• Method conversely, a method of dispersing a tetracarboxylic acid component in a solvent, or a method of adding a diamine component to a dissolved solution, a method of alternately adding a diamine component and a tetracarboxylic acid component to the reaction system, and the like, Any of these methods may be used.
• the temperature at which the diamine component and the tetracarboxylic acid component are polycondensed can be selected at any temperature from -20 to 150°C, but is preferably in the range from -5 to 100°C.
• the reaction can be carried out at any concentration, but if the concentration is too low it will be difficult to obtain a high molecular weight polymer, and if the concentration is too high the viscosity of the reaction solution will be too high and uniform stirring will be difficult. .. Therefore, the concentration of the polymer is preferably 1 to 50% by mass, more preferably 5 to 30% by mass.
• the reaction can be performed at a high concentration in the initial stage, and then a solvent can be added.
• the ratio of the total mole number of the tetracarboxylic acid component to the total mole number of the diamine component is preferably 0.8 to 1.2. Similar to the usual polycondensation reaction, the closer the molar ratio is to 1.0, the larger the molecular weight of the polyimide precursor produced.
• Polyimide is obtained by ring-closing a polyimide precursor.
• the ring closure rate (also referred to as imidization rate) of the amic acid group (amido acid group) does not necessarily have to be 100%, and can be arbitrarily adjusted according to the application and purpose.
• the method for imidizing the polyimide precursor include thermal imidization in which the solution of the polyimide precursor is heated as it is, and catalytic imidization in which a catalyst is added to the solution of the polyimide precursor.
• the temperature is preferably 100 to 400° C., more preferably 120 to 250° C., and a method is preferably performed while removing water generated by the imidization reaction outside the system. ..
• Catalytic imidization of the polyimide precursor can be carried out by adding a basic catalyst and an acid anhydride to a solution of the polyimide precursor and stirring the mixture at -20 to 250°C, preferably 0 to 180°C.
• the amount of the basic catalyst is preferably 0.5 to 30 mol times, more preferably 2 to 20 mol times the amic acid group, and the amount of acid anhydride is preferably 1 to 50 mol times the amic acid group. , And more preferably 3 to 30 times by mole.
• the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine and the like. Of these, pyridine is preferable because it has an appropriate basicity to allow the reaction to proceed.
• the acid anhydride include acetic anhydride, trimellitic anhydride, pyromellitic anhydride and the like. Particularly, acetic anhydride is preferable because purification after the reaction is facilitated.
• the imidation ratio by catalytic imidization can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time.
• the reaction solution may be poured into a solvent for precipitation.
• the solvent used for precipitation include methanol, ethanol, isopropyl alcohol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, water and the like.
• the polymer precipitated by pouring it into a solvent can be collected by filtration, and then dried at normal temperature or under normal temperature or by heating.
• the impurities in the polymer can be reduced by repeating the operation of re-dissolving the polymer recovered by precipitation and re-precipitating and recovering it in a solvent 2 to 10 times.
• the solvent at this time include alcohols, ketones, hydrocarbons and the like. It is preferable to use three or more kinds of solvents selected from these, because the efficiency of purification is further improved.
• the polyimide precursor when the polyimide precursor is a polyamic acid ester, a specific method for producing it is, for example, the method described in paragraphs [0054] to [0062] of International Publication WO 2011-115077.
• the terminal of the polyimide precursor or the polyimide obtained therefrom may be modified with a terminal modifier. By modifying the ends, the effect of enhancing the adhesiveness between the sealant and the liquid crystal alignment film can be obtained.
• terminal modifying agent examples include tert-butyloxycarbonylating agents, N-tert-butoxycarbonylimidazole, tert-butylphenyl carbonate, tert-butyl carbazate, tert-butyl chloroformate, di-tert-butyl dicarbonate. Etc. As the end modifier, di-tert-butyl dicarbonate is preferred.
• An embodiment of the present invention is a liquid crystal aligning agent containing a polymer (A), a polymer (B) and a polymer (C).
• the content of the polymer (A) in the liquid crystal aligning agent is preferably 10 to 50% by mass based on the total amount of the polymers (A) to (C) of 100% by mass from the viewpoint of the liquid crystal alignment regulating force. And more preferably 10 to 30% by mass.
• the content of the polymer (B) in the liquid crystal aligning agent is preferably 10 to 70% by mass based on 100% by mass of the total amount of the polymers (A) to (C) from the viewpoint of relaxation characteristics of accumulated charges. And more preferably 40 to 60% by mass.
• the content of the polymer (C) in the liquid crystal aligning agent is preferably 10 to 50% by mass based on the total amount of the polymers (A) to (C) of 100% by mass from the viewpoint of the accumulated charge amount of DC. And more preferably 10 to 30% by mass.
• the liquid crystal aligning agent of the present invention may contain a polymer other than the polymers (A) to (C).
• examples of other polymers include cellulosic polymers, acrylic polymers, methacrylic polymers, polystyrene, polyamides, polysiloxanes and the like.
• the content of the other polymers other than that is preferably 0.5 to 15 parts by mass, and more preferably 1 to 10 parts by mass with respect to 100 parts by mass in total of the polymers (A) to (C).
• the liquid crystal aligning agent is usually contained in an organic solvent, and the content of the organic solvent is preferably 70 to 99.9 mass% with respect to the liquid crystal aligning agent. This content can be appropriately changed depending on the application method of the liquid crystal aligning agent and the target film thickness of the liquid crystal aligning film.
• the organic solvent used for the liquid crystal aligning agent is preferably a solvent (also referred to as a good solvent) capable of dissolving the polymers (A) to (C).
• N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide or ⁇ -butyrolactone can be used. preferable.
• the good solvent in the liquid crystal aligning agent of the present invention is preferably 20 to 99% by mass, more preferably 20 to 90% by mass, and particularly preferably 30 to 80% by mass based on the whole solvent contained in the liquid crystal aligning agent. Is.
• a solvent also referred to as a poor solvent
• ethylene glycol dimethyl ether ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether , 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene Gly
• preferred solvent combinations are N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone and ⁇ -butyrolactone and ethylene glycol monobutyl ether, and N-methyl-2-pyrrolidone and ⁇ -.
• the amount of the poor solvent is preferably 1 to 80% by mass, more preferably 10 to 80% by mass, and particularly preferably 20 to 70% by mass, based on the whole solvent contained in the liquid crystal aligning agent.
• the type and content of such a solvent are appropriately selected according to the liquid crystal alignment agent coating device, coating conditions, coating environment, and the like.
• the liquid crystal aligning agent of the present invention includes a dielectric for the purpose of changing the electrical properties such as the dielectric constant and conductivity of the liquid crystal aligning film, a silane coupling agent for improving the adhesion between the liquid crystal aligning film and the substrate, and a liquid crystal.
• Examples of the compound that improves the adhesion between the liquid crystal alignment film and the substrate include a functional silane-containing compound and an epoxy group-containing compound. Examples thereof include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and 3-aminopropyltriethoxysilane.
• additives (CL-1) to (CL-15) may be added to the liquid crystal aligning agent of the present invention in order to increase the mechanical strength of the liquid crystal aligning film.
• the content of the above additives is preferably 0.1 to 30 parts by mass with respect to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent. More preferably, it is 0.5 to 20 parts by mass.
• the liquid crystal alignment film is obtained by coating the above liquid crystal aligning agent on a substrate to form a film, preferably drying, and then baking.
• a substrate having high transparency is preferable, and as the material thereof, glass, ceramics such as silicon nitride, plastic such as acrylic or polycarbonate, and the like can be used. It is preferable to use a substrate on which an ITO (Indium Tin Oxide) electrode for driving the liquid crystal is formed as the substrate from the viewpoint of simplifying the process.
• an opaque material such as a silicon wafer can be used for the substrate on one side, and a material that reflects light such as aluminum can be used for the electrode.
• the film is preferably heated at 30 to 120° C., more preferably at 50 to 120° C. by a heating means such as a hot plate, a heat circulation type oven, an IR (infrared) type oven. It is preferable to evaporate the solvent by drying treatment for 1 minute to 10 minutes, more preferably 1 minute to 5 minutes.
• the coating film obtained from the liquid crystal aligning agent is then preferably heated at 120 to 250° C., more preferably 150° C., by the same heating means as in the above drying treatment. It is baked at ⁇ 230°C.
• the firing time varies depending on the firing temperature, but is preferably 5 minutes to 1 hour, more preferably 5 minutes to 40 minutes.
• the thickness of the coating film after the baking treatment is not particularly limited, but if it is too thin, the reliability of the liquid crystal display element may decrease, and if it is too thick, the electric resistance of the obtained liquid crystal alignment film increases, so that it is 5 to 300 nm. Is preferable, and 10 to 200 nm is more preferable.
• the obtained coating film is oriented. Examples of the alignment treatment method include a rubbing treatment method and a photo-alignment treatment method.
• the surface of the coating film is irradiated with radiation polarized in a certain direction.
• the radiation ultraviolet rays or visible rays having a wavelength of 100 to 800 nm can be used. Among them, ultraviolet rays having a wavelength of 100 to 400 nm are preferable, and ultraviolet rays having a wavelength of 200 to 400 nm are more preferable.
• the substrate coated with the liquid crystal alignment film may be irradiated with ultraviolet rays while being heated at 50 to 250° C.
• the irradiation dose of the radiation is preferably 1 to 10,000 mJ/cm2. Among them, 100 to 5,000 mJ/cm2 is preferable.
• the liquid crystal alignment film thus produced can stably align liquid crystal molecules in a certain direction.
• the extinction ratio of linearly polarized ultraviolet rays is preferably 10:1 or more, more preferably 20:1 or more.
• At least one treatment selected from the group consisting of heat treatment and contact treatment with a solvent may be further applied to the coating film subjected to the above-mentioned orientation treatment.
• the heat treatment after the orientation treatment can be performed by the same heating means as the above-mentioned drying treatment and firing treatment, and is preferably performed at 180 to 250°C, more preferably 180 to 230°C.
• the heat treatment temperature is within the above range, the contrast of the liquid crystal display device obtained by the obtained liquid crystal alignment film can be increased.
• the time of the heat treatment varies depending on the heating temperature, but is preferably 5 minutes to 1 hour, more preferably 5 to 40 minutes.
• the solvent used for the contact treatment with the above solvent is not particularly limited as long as it is a solvent capable of dissolving impurities and the like attached to the liquid crystal alignment film.
• Specific examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, 3- Methyl methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, cyclohexyl acetate and the like can be mentioned.
• water, 2-propanol, 1-methoxy-2-propanol or ethyl lactate is preferable from the viewpoint of versatility and solvent safety. More preferred is water, 1-methoxy-2-propanol or ethyl lactate.
• These solvents may be one kind or two or more kinds.
• the contact treatment includes dipping treatment and spraying treatment (also referred to as spraying treatment).
• the treatment time in these treatments is preferably 10 seconds to 1 hour, and particularly, an embodiment in which the immersion treatment is performed for 1 to 30 minutes can be mentioned.
• the temperature at the time of contact treatment may be room temperature or warming, but is preferably 10 to 80° C., and 20 to 50° C. is mentioned.
• ultrasonic treatment or the like may be further performed, if necessary.
• rinsing also referred to as rinsing
• a low boiling point solvent such as water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, or the like
• drying may be performed at that time.
• the drying temperature is preferably 50 to 150°C, and may be 80 to 120°C.
• the drying time is preferably 10 seconds to 30 minutes, more preferably 1 to 10 minutes.
• the liquid crystal alignment film of the present invention can be applied to various driving modes such as a TN method, an STN method, an IPS method, an FFS method, a VA method, an MVA method and a PSA method. It is suitable as a liquid crystal alignment film for an electric field type liquid crystal display element, and is particularly useful for an FFS type liquid crystal display element.
• the liquid crystal display device of the present invention is a device in which a liquid crystal cell is prepared by a known method after a substrate having a liquid crystal alignment film obtained from the above liquid crystal alignment agent is obtained.
• a liquid crystal display element having a passive matrix structure will be described as an example.
• a liquid crystal display element having an active matrix structure in which a switching element such as a TFT is provided in each pixel portion forming an image display may be used.
• a transparent glass substrate is prepared, a common electrode is provided on one substrate, and a segment electrode is provided on the other substrate.
• These electrodes can be, for example, ITO electrodes and are patterned so that a desired image can be displayed.
• an insulating film is provided on each substrate so as to cover the common electrodes and the segment electrodes.
• the insulating film can be, for example, a film made of SiO 2 —TiO 2 formed by a sol-gel method.
• a liquid crystal alignment film is formed on each substrate, and one substrate is overlaid with the other substrate so that the liquid crystal alignment film surfaces face each other. Glue with.
• a spacer In order to control the gap between the substrates, it is usually preferable to incorporate a spacer into the sealant. Further, it is preferable that spacers for controlling the substrate gap are also scattered on the in-plane portion where the sealant is not provided. It is preferable that a part of the sealant is provided with an opening that can be filled with liquid crystal from the outside.
• a liquid crystal material is injected into a space surrounded by the two substrates and the sealant through an opening provided in the sealant. Next, this opening is sealed with an adhesive.
• the liquid crystal material may have either positive or negative dielectric anisotropy.
• a liquid crystal having a negative dielectric anisotropy is preferable from the viewpoint of liquid crystal orientation, but it can be used properly according to the application.
• the polarizing plate is installed. Specifically, it is preferable to attach a pair of polarizing plates to the surfaces of the two substrates opposite to the liquid crystal layer.
• This solution was measured for proton NMR at 500 MHz with an NMR measuring device (JNW-ECA500) (manufactured by JEOL Datum).
• PA-I polyamic acid solution
• 100.0 g of the obtained polyamic acid solution (PA-I) was placed in a 100 mL four-necked flask equipped with a stirrer and a nitrogen introducing tube, and di-tert-butyl dicarbonate (Boc2O) as a terminal modifier was added to 4 After adding 0.06 g (18.6 mmol) and stirring at 40° C. for 15 hours, a terminal-modified polyamic acid solution (PAboc-I) was obtained.
• the resulting resin powder was vacuum dried at 80° C. for 12 hours to obtain a polyimide (SPI1-1) powder.
• the imidation ratio of this polyimide resin powder was 75%.
• NMP was added to the obtained polyimide (SPI1-1) so that the solid content concentration was 15% by mass, and the mixture was stirred at 70° C. for 15 hours to prepare a solution of the polyimide (SPI1-1) having a solid content concentration of 15% by mass. Obtained.
• a liquid crystal cell having a configuration of a fringe field switching (FFS) mode liquid crystal display device is manufactured.
• a substrate with electrodes was prepared.
• the substrate is a glass substrate having a size of 35 mm ⁇ 40 mm and a thickness of 0.7 mm.
• a SiN (silicon nitride) film formed by the CVD method is formed on the counter electrode of the first layer.
• the film thickness of the second-layer SiN film is 500 nm and functions as an interlayer insulating film.
• a comb-teeth-shaped pixel electrode formed by patterning an ITO film is arranged as a third layer on the second-layer SiN film to form two pixels, a first pixel and a second pixel. ing.
• the size of each pixel is 10 mm in length and about 5 mm in width.
• the counter electrode of the first layer and the pixel electrode of the third layer are electrically insulated by the action of the SiN film of the second layer.
• the third-layer pixel electrode has a comb-tooth shape formed by arranging a plurality of V-shaped electrode elements whose central portion is bent.
• the width of each electrode element in the lateral direction is 3 ⁇ m, and the distance between the electrode elements is 6 ⁇ m.
• the pixel electrode that forms each pixel is configured by arranging a plurality of bent V-shaped electrode elements in the central portion, the shape of each pixel is not rectangular, but is similar to the electrode element in the central portion. It has a shape that bends and resembles a bold "dogleg".
• Each pixel is divided into upper and lower parts with a central bent portion as a boundary, and has a first region on the upper side and a second region on the lower side of the bent portion.
• the forming directions of the electrode elements of the pixel electrodes forming them are different. That is, when the rubbing direction of the liquid crystal alignment film described later is used as a reference, the electrode elements of the pixel electrode are formed to form an angle (clockwise) of +10° in the first region of the pixel, and the pixel element is formed in the second region of the pixel.
• the electrode element of the electrode is formed so as to form an angle (clockwise) of ⁇ 10°. That is, in the first region and the second region of each pixel, the directions of the rotation operation (in-plane switching) of the liquid crystal, which is induced by the voltage application between the pixel electrode and the counter electrode, in the plane of the substrate are mutually different. It is configured to be in the opposite direction.
• the liquid crystal aligning agent was filtered through a 1.0 ⁇ m filter onto a glass substrate having a columnar spacer having a height of 4 ⁇ m and an ITO film formed on the back surface of the liquid crystal aligning agent by spin coating. Applied and dried on a hot plate at 80° C. for 2 minutes. Then, baking was performed for 30 minutes in a hot air circulation type oven at 230° C. to obtain a substrate with a liquid crystal alignment film having a film thickness of 100 nm.
• the surface of the substrate with the liquid crystal alignment film was rubbed with a rayon cloth (YA-20R manufactured by Yoshikawa Kako) (roller diameter: 120 mm, roller rotation speed: 1000 rpm, moving speed: 20 mm/sec, pushing length: 0.4 mm), and then pure. Ultrasonic irradiation in water was carried out for 1 minute to wash, water droplets were removed by air blow, and then dried at 80° C. for 15 minutes to obtain a substrate with a liquid crystal alignment film.
• the obtained two substrates with a liquid crystal alignment film are set as one set, the sealant is printed on the substrate with the liquid crystal injection port left, and the other substrate is faced with the liquid crystal alignment film and the rubbing direction is They were laminated in antiparallel.
• Liquid crystal MLC-3019 manufactured by Merck & Co., Inc.
• the injection port was sealed to obtain an FFS type liquid crystal display element.
• the obtained liquid crystal display device was heated at 120° C. for 1 hour and left at 23° C. overnight, and then used for evaluation.
• VT curve voltage-transmittance curve
• the case where the amount of accumulated DC is 150 mV or less is considered to be particularly good.
• the FFS-driving liquid crystal cell prepared above is placed between two polarizing plates arranged so that their polarization axes are orthogonal to each other, and the pixel electrode and the counter electrode are short-circuited to have the same potential.
• the LED backlight was irradiated from under the polarizing plate, and the angle of the liquid crystal cell was adjusted so that the brightness of the LED backlight transmitted light measured on the two polarizing plates was minimized. This evaluation was carried out under the temperature condition where the temperature of the liquid crystal cell was 23°C.
• VT curve voltage-transmittance curve
• an alternating voltage at which the relative transmittance was 23% or 100% was calculated as a driving voltage.
• a rectangular wave of 20 mV was applied to the liquid crystal cell at 23° C. at a frequency of 1 kHz for 30 minutes.
• the VT characteristic voltage-transmittance characteristic
• the VT characteristic voltage-transmittance characteristic at a temperature of 23° C. was measured, and an AC voltage at which the relative transmittance was 23% was calculated. ..
• this AC voltage corresponds to a region where the change in brightness with respect to the voltage is large, it is convenient to evaluate the accumulated charge through the brightness.
• a DC voltage of +1.0 V was superimposed and driven for 30 minutes.
• the direct current voltage was cut off, and an alternating current voltage having a relative transmittance of 23% was applied again, and only a rectangular wave having a frequency of 30 Hz was applied for 30 minutes. The faster the relaxation of the accumulated charge, the faster the accumulation of the charge in the liquid crystal cell when the DC voltage is superimposed.
• the relaxation characteristic of the accumulated charge is that the relative transmittance immediately after the DC voltage is superimposed is 30% or more. It evaluated by the time taken until it fell to 23%. It can be said that the shorter the time is, the better the relaxation characteristic of the accumulated charge is. Specifically, the time during which the relative transmittance decreased to 30% or less was quantified by the time when 30 minutes passed from the time when the application of the DC voltage was started. “ ⁇ ” when the relative transmittance decreased to 30% or less within 10 minutes, “ ⁇ ” when the relative transmittance exceeded 10 minutes and within 20 minutes, and “ ⁇ ” when the relative transmittance exceeded 30 minutes within 20 minutes. When the relative transmittance did not decrease to 30% or less in 30 minutes, it was evaluated as “x”.
• a liquid crystal cell is installed between two polarizing plates arranged so that their polarization axes are orthogonal to each other, a backlight is turned on, and the liquid crystal cell is arranged so that the transmitted light intensity of the first region of the pixel is minimized.
• the arrangement angle was adjusted, and then the rotation angle required when the liquid crystal cell was rotated so that the transmitted light intensity of the second region of the pixel was minimized was obtained. It can be said that the smaller the value of the rotation angle, the better the afterimage characteristics due to the long-term AC drive.
• “ ⁇ ” when the rotation angle is 0.5 degrees or less “ ⁇ ” when the rotation angle exceeds 0.5 degrees and 1.0 degree or less, and 1.5 degrees when the rotation angle exceeds 1.0 degrees. In the case of the following, it was evaluated as “ ⁇ ”, and when it exceeded 2.0 degrees, it was evaluated as “x”.
• the liquid crystal display element using the liquid crystal aligning agent of the example of the present invention has a high degree of compatibility with other characteristics while suppressing the amount of DC accumulation.
• the liquid crystal aligning agent of the present invention is useful for forming a liquid crystal aligning film in a wide range of liquid crystal display devices such as an IPS driving system and an FFS driving system.

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