Classifications

• • 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
  • 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
• • 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

Definitions

• Liquid crystal alignment agent for vertical alignment and liquid crystal display device Liquid crystal alignment agent for vertical alignment and liquid crystal display device
• the present invention relates to a liquid crystal alignment treatment agent used for forming a liquid crystal alignment film of a vertical alignment type liquid crystal display element, and a liquid crystal display element manufactured using the same.
• the basic structure of a liquid crystal display element is a structure in which a liquid crystal material is filled between two opposing substrates, and the liquid crystal material has a desired initial alignment state by the action of a liquid crystal alignment film provided on the substrate surface.
• a liquid crystal alignment film a polyimide resin film having excellent heat resistance has been mainly used, and it has realized vertical alignment and horizontal alignment with respect to a substrate.
• a method of introducing a long alkyl chain into polyamic acid or polyimide for example, see Patent Document 1
• a method of introducing a cyclic substituent for example, see Patent Documents 2 and 3 are known. Have been.
• a characteristic obtained by a simple liquid crystal cell called a voltage holding ratio is known.
• a high voltage holding ratio can be obtained by using an acid dianhydride having an aliphatic cyclic structure. It is known (see, for example, Patent Documents 4, 5, and 6).
• Patent Documents 4, 5, and 6 See, for example, Patent Documents 4, 5, and 6.
• these are techniques for increasing the voltage holding ratio at high temperatures, and have a high voltage holding ratio at high temperatures and stabilize the voltage holding ratio against high-temperature aging which is an index indicating long-term reliability. The method has been reported so far.
• Patent Document 1 Japanese Patent Application Laid-Open No. 6-3678
• Patent Document 2 Japanese Patent Application Laid-Open No. 9-278724
• Patent Document 3 JP 2001-311080 A
• Patent Document 4 JP-A-5-341129
• Patent Document 6 JP-A-11-84391
• a liquid crystal aligning agent for vertical alignment comprising at least one polymer of the obtained polyamic acid or the dehydrated ring-closure of the polyamic acid.
• ⁇ represents a single bond or a divalent bonding group selected from the group consisting of ethers, esters, amides, and urethanes.
• X is a linear alkyl group having 8 to 20 carbon atoms.
• R represents a linear hydrocarbon group having 1 to 12 carbon atoms or a branched hydrocarbon group having 1 to 12 carbon atoms, and R represents a hydrogen atom, a line having 1 to 12 carbon atoms. Hydrocarbon group, or
• R and R independently represent a hydrogen atom or
• the diamine having the structure represented by the formula (1) is 10 to 80 mol% and the diamine having the structure represented by the formula (2) is 20 to 90 mol%.
• Liquid crystal alignment agent for alignment is 10 to 80 mol% and the diamine having the structure represented by the formula (2).
• a liquid crystal alignment film for vertical alignment having excellent voltage holding characteristics at high temperatures and excellent aging resistance at high temperatures can be formed, and a high-quality display can be stably performed over a long period of time.
• a liquid crystal display device capable of performing the above operation is obtained.
• the vertical alignment type liquid crystal aligning agent of the present invention has a diamine component having a diamine having a structure represented by the formula (1) and a diamine having a structure represented by the formula (2), and an alicyclic structure. It is a liquid crystal aligning agent for vertical alignment containing at least one of a polyamic acid obtained by reacting with tetracarboxylic dianhydride and a dehydrated ring-closed product of the polyamic acid.
• Diamine having a structure represented by the formula (1) is used for imparting vertical alignment to a liquid crystal alignment film obtained from the liquid crystal alignment treatment agent of the present invention.
• the amount used is preferably at least 10 mol% of the total diamine component used in the reaction to obtain the polyamic acid, and is preferably at least 20 mol%, particularly preferably at least 30 mol%, in order to secure the stability of vertical alignment. It is. [0014] Also, from the relationship with the preferred amount of diamine having a structure represented by the formula (2) described later, 80 mol. / o or less, more preferably 70 mol% or less. Further, from the viewpoint of printability when the liquid crystal alignment treatment agent of the present invention is used as a coating solution, the content is preferably 60 mol% or less.
• X is a single bond or an ether, ester, amide, or urethane
• X is a linear alkyl group having 8 to 20 carbon atoms, or X
• the straight-chain alkyl group preferably has 12 to 18 carbon atoms, and more preferably 16 to 18 carbon atoms.
• the alicyclic skeleton having 414 carbon atoms includes monocyclic skeletons such as cyclobutane, cyclopentane and cyclohexane, skeletons combining two or more of these single rings, and steroids such as cholesterol and cholestanol. And a skeleton.
• the monovalent organic group having an alicyclic skeleton preferably has at least one alkyl group having 5 to 12 carbon atoms.
• the preferred position of the two amino groups is X, 2,2 on the benzene ring.
• diamine having the structure represented by the formula (1) are shown below, but are not limited thereto.
• Diamines having an alkyl group such as 1,3-diamino_4-octadecyloxybenzene, 1,3-diamino_4_hexadecyloxybenzene, and 1,3-diamino_4-dodecyloxybenzene.
• Diamine having a structure in a side chain A diamine having a steroid structure represented by the following formula (4)-(6). [0018] [Formula 4]
• 4_ [4_trans-n-heptylcyclohexyl) phenoxy 3-diaminobenzene, (4-trans-n-pentylbicyclohexyl) -3,5-diaminobenzoate and other liquid crystal-like structures are used as side chains. Is preferred because of excellent stability of vertical alignment.
• Diamine having a structure represented by the formula (2) is used for imparting stability to aging of a voltage holding ratio, and is characterized by having an N-arylaniline structure.
• the use amount is preferably 20 mol% or more, more preferably 30 mol% or more of the whole diamine component used in the reaction for obtaining polyamic acid.
• Omol% or less is preferable.
• the preferred position of the two amino groups is the 2,4 position, the 2,5 position, or the 3,5 position on the benzene ring with respect to the N-aryl group.
• the hydrocarbon group preferably contains a carbon-carbon double bond, more preferably the double bond is between the second and third carbon atoms from the nitrogen atom.
• the carbon number of R is 6 or less from the viewpoint of printability of the liquid crystal alignment agent. It is preferably 3 or less, more preferably 3 or less.
• R is a hydrogen atom, a linear hydrocarbon group having 1 to 12 carbon atoms, or a carbon atom.
• R is a hydrogen atom
• a preferred example of the diamine having the structure represented by the formula (2) is, for example, the structure of the following formula (3).
• the polyamic acid in the present invention comprises a diamine component containing a diamine having a structure represented by the formula (1) and a diamine component having a structure represented by the formula (2), and a tetracarboxylic dianhydride component having an alicyclic structure. It is obtained by reacting.
• the diamine component and the tetracarboxylic dianhydride component are reacted by supplying the former at a ratio of preferably 0.91 to 11 mol, particularly 0.95 to 1.05 mol, with respect to the former lmol.
• the polyamic acid used in the liquid crystal alignment treatment agent of the present invention has a weight average molecular weight ⁇ Mw ⁇ measured by GPC (Gel Permeation Chromatography) method of preferably 21,500,000, particularly preferably 51,200,000. It is preferred to do so. If the molecular weight is too small, the strength of the coating film obtained therefrom will be insufficient, and if the molecular weight is too large, the workability at the time of forming the coating film may deteriorate.
• the molecular weight of the polyamic acid can be controlled by adjusting the molar ratio of the diamine component and the tetracarboxylic dianhydride used in the synthesis reaction of the polyamic acid. As in the ordinary polycondensation reaction, the closer the molar ratio is to 1.0, the higher the degree of polymerization of the produced polymer becomes.
• dehydrated ring closure of polyamic acid examples include polyimide.
• dehydrated ring-closure of polyamic acid referred to herein includes those in which all of the repeating units of the polyamic acid are not dehydrated and ring-closed, but is included in the category, and is also suitable for the liquid crystal alignment treatment agent of the present invention. Used.
• imidation (dehydration ring closure) of a polyamic acid can be performed in a solution.
• the reaction temperature is usually 50 to 200 ° C, preferably 60 to 170 ° C. If the reaction temperature is lower than 50 ° C, the dehydration ring-closing reaction does not proceed sufficiently, and if the reaction temperature is higher than 200 ° C, the molecular weight of the obtained imidized polymer is reduced.
• the use amount of the dehydration ring-closing catalyst is preferably 0.01 to 10 mol per 1 mol of the dehydrating agent used.
• the organic solvent used for the dehydration ring closure reaction the organic solvents exemplified as those used for the synthesis of polyamic acid can be exemplified.
• the reaction temperature when a dehydrating agent and / or a dehydration ring-closing catalyst is added is usually 0 to 180 ° C, preferably 10 to 150 ° C.
• the polyamic acid or polyimide obtained as described above can be used as it is. Alternatively, it can be used after precipitation and isolation in a poor solvent such as methanol or ethanol.
• polymer having another structure examples include one or more tetracarboxylic dianhydrides selected from the following tetracarboxylic dianhydrides and diamine compounds, and one or more diamine dianhydrides.
• tetracarboxylic dianhydrides selected from the following tetracarboxylic dianhydrides and diamine compounds, and one or more diamine dianhydrides.
• Polyamic acid and its dehydrated ring-closed product obtained by the reaction with a product but are not limited thereto.
• Tetracarboxylic dianhydride pyromellitic acid, 2,3,6,7_naphthalenetetracarboxylic acid, 1,2,5,6_naphthalenetetracarboxylic acid, 1,4,5,8_naphthalenetetra Carboxylic acid, 2,3,6,7_anthracenetetracarboxylic acid, 1,2,5,6_anthracenetetracarboxylic acid, 3,3,4,4'-biphenyltetracarboxylic acid, 2,3, 3,, 4-biphenyltetracarboxylic acid, bis (3,4-dicarboxyphenyl) ether, 3,3'4,4'-benzophenonetetracarboxylic acid, 3,3'4,4'_chalconetetra Carboxylic acid, bis (3,4-dicarboxy Phenyl) sulfone, bis (3,4-dicarboxyphenyl) methane, 2,2-bis (3,4-dicanololebox
• Diamine compounds p-phenylenediamine, m-phenylenediamine, 2,4-diamino-N, N-diallylaniline, 2,5-diaminobenzonitrile, 2,5-diaminotoluene, 2,6-diaminotoluene, 4,4 , -Diaminobiphenyl, 3,3, -dimethyl-4,4, -diaminobiphenyl, 3,3,1-dimethoxy-4,4, diaminobiphenyl, diaminodiphenylmethane, diaminodiphenylether, diaminodiphenyl 2,2'-diaminodiphenylpropane, bis (3,5-ethylamino-4-phenylamino) methane, diaminodiphenylsulfone, diaminobenzophenone, 3,3'-diaminochalcone, 4,4'-diaminochalcone, 3, 3'-
• the liquid crystal alignment treatment agent of the present invention may contain a functional silane-containing compound for imparting adhesion to a substrate.
• a functional silane-containing compound for imparting adhesion to a substrate.
• silane bis (ethylamino) dimethylsilane, 1-trimethylsilylimidazole, methyltriacetoxysilane, ethoxymethylphenylsilane, phenyltriethoxysilane, and diphenylsilanediol.
• the transfer printing method is widely used industrially. It is also suitably used in agents.
• the drying step after the application of the liquid crystal alignment treatment agent is not necessarily required, but the time from application to one baking is not constant for each substrate, or baking is not performed immediately after the application. In this case, it is preferable to include a drying step.
• the drying means is not particularly limited as long as the solvent is evaporated to such an extent that the shape of the coating film is not deformed by the transport of the substrate or the like.
• a method of drying on a hot plate at 50 to 150 ° C., preferably 80 to 120 ° C., for 0.5 to 30 minutes, preferably 115 minutes may be employed.
• the firing of the liquid crystal alignment treatment agent can be performed at an arbitrary temperature of 100 to 350 ° C, preferably 150. C-1 300. C, and even more preferred is 200. C-250.
• C. Liquid crystal alignment treatment When the polyamic acid is contained in the agent, the conversion rate from polyamic acid to polyimide changes depending on the calcination temperature, but the liquid crystal alignment treatment agent of the present invention does not necessarily need to be imidized at 100%. However, it is preferable that the baking is performed at a temperature higher by 10 ° C. or more than a heat treatment temperature required for a liquid crystal cell manufacturing process, such as curing of a sealant, regardless of whether polyamic acid is contained.
• the thickness of the coating film after baking is too large, it is disadvantageous in terms of power consumption of the liquid crystal display element, and if it is too thin, the reliability of the liquid crystal display element may be reduced, so that the thickness is 5 to 300 nm, preferably 10 to 100 nm. Oh.
• the liquid crystal display device of the present invention is obtained by obtaining a substrate with a liquid crystal alignment film from the liquid crystal alignment agent of the present invention by the above-described method, and then forming a liquid crystal cell by a known method to obtain a liquid crystal display device.
• a pair of substrates on which a liquid crystal alignment film is formed is fixed with a sealant with a spacer of 30 ⁇ , preferably 2-10 ⁇ , A method of injecting a liquid crystal and sealing is common.
• the method of sealing the liquid crystal is not particularly limited, and examples thereof include a vacuum method in which the pressure in the manufactured liquid crystal cell is reduced and then the liquid crystal is injected, and a dropping method in which the liquid crystal is dropped and then sealed.
• the substrate used for the liquid crystal display element is not particularly limited as long as it is a substrate having high transparency, and a glass substrate, a plastic substrate such as an acrylic substrate or a polycarbonate substrate, or the like can be used. Among them, it is preferable to use a substrate on which a negative electrode or the like for driving a liquid crystal is formed from the viewpoint of simplifying the process.
• a reflection type liquid crystal display device an opaque material such as a silicon wafer can be used as long as only one substrate is used. In this case, a material which reflects light such as aluminum can be used.
• This liquid crystal alignment treatment agent was subjected to pressure filtration with a membrane filter having a pore size of 0.5 ⁇ m, and then spin-coated on a glass substrate with a transparent electrode.
• the substrate was placed on a hot plate at 80 ° C., dried for 5 minutes, and baked in a hot air circulating oven at 210 ° C. for 60 minutes to obtain a 100 nm thick liquid crystal alignment film on the substrate.
• the liquid crystal cell was placed in a constant temperature bath at 80 ° C, and a voltage of ⁇ 4 V, a pulse width of 0.06 ms and a frame of The voltage holding ratio was measured by the voltage ratio under the condition of a period of 16.67 ms. As a result, the voltage holding ratio at 80 ° C showed a very high value of 97.9%. Further, after aging treatment of this liquid crystal cell at 120 ° C for one week, the voltage holding ratio at 80 ° C was measured again in the same manner, and it was found that the voltage holding ratio was as high as 94.1%. Was. In addition, when the alignment state of the liquid crystal after aging was observed with a polarizing microscope, it was confirmed that the liquid crystal had a uniform vertical alignment without any defect.
• the voltage holding ratio of this liquid crystal cell was evaluated in the same manner as in Example 1. As a result, the voltage holding ratio at 80 ° C before aging showed a very high value of 97.7%. Furthermore, the voltage holding ratio at 80 ° C after aging treatment at 120 ° C for one week maintained a very high value of 96.1%. In addition, when the alignment state of the liquid crystal after aging was observed with a polarizing microscope, it was confirmed that the liquid crystal had a uniform vertical alignment without any defect.
• This liquid crystal alignment agent was subjected to the same treatment as in Example 1 to produce a liquid crystal cell. Observation of the alignment state of the liquid crystal with a polarizing microscope confirmed that the liquid crystal had a uniform vertical alignment without any defects.
• the voltage holding ratio of this liquid crystal cell was evaluated in the same manner as in Example 1. As a result, the voltage holding ratio at 80 ° C before aging showed a very high value of 97.9%. Furthermore, the voltage holding ratio at 80 ° C after aging treatment at 120 ° C for one week maintained a very high value of 95.5%. In addition, when the alignment state of the liquid crystal after aging was observed with a polarizing microscope, it was confirmed that the liquid crystal had a uniform vertical alignment without any defect.
• Example 4 12.20 g (0.06 mol) of 2,4-diamino-N, N-dialinoleadiline represented by the formula (7) and 15.07 g (0,0) of 1,3-diamino-14-octadecyloxybenzene O4mol) was added with NMP186.7g (the melting angle ratio, this (1,2,3,4, -cyclobutanetetranorenoleic acid dianhydride 19.41g (0.099mol)) was added, and the mixture was allowed to stand at room temperature for 24 hours. reacted to obtain a solution of polyamic acid. the weight average molecular weight of the obtained polyamic acid ⁇ Mw ⁇ was 44000. the solution 30g added NMP50g and ethylene glycol _ n _ ether 20g to sufficiently stirred to uniformly Thus, a liquid crystal alignment treating agent of the present invention having a concentration of 6 wt% was obtained.
• This liquid crystal alignment agent was subjected to the same treatment as in Example 1 to produce a liquid crystal cell. Observation of the alignment state of the liquid crystal with a polarizing microscope confirmed that the liquid crystal had a uniform vertical alignment without any defects.
• the voltage holding ratio of this liquid crystal cell was evaluated in the same manner as in Example 1. As a result, the voltage holding ratio at 80 ° C before aging showed a very high value of 96.4%. Furthermore, the voltage holding ratio at 80 ° C after aging treatment at 120 ° C for one week maintained a very high value of 92.2%. In addition, when the alignment state of the liquid crystal after aging was observed with a polarizing microscope, it was confirmed that the liquid crystal had a uniform vertical alignment without any defect.
• the imidation ratio was determined by 1 H-NMR measurement from the integral ratio of the remaining protons derived from the amide group and the protons derived from the methyl group.
• 6g of the above-obtained polyimide powder was dissolved in 74g of NMP, and 20g of ethylene glycol-n-butyl ether was further dissolved and stirred sufficiently to form a uniform solution.
• the liquid crystal alignment treatment of the present invention having a concentration of 6wt% was performed. Agent was obtained.
• the voltage holding ratio of this liquid crystal cell was evaluated in the same manner as in Example 1. As a result, the voltage holding ratio at 80 ° C before aging showed a very high value of 97.9%. Furthermore, the voltage holding ratio at 80 ° C after aging treatment at 120 ° C for 1 week maintained a very high value of 93.0%. In addition, when the alignment state of the liquid crystal after aging was observed with a polarizing microscope, it was confirmed that the liquid crystal had a uniform vertical alignment without any defect.
• a polyimide powder was obtained in the same manner as in Example 5, except that the imidization condition of the polyamic acid solution was changed from 30 ° C / 4 hours to 40 ° C / 4 hours.
• the weight average molecular weight ⁇ Mw ⁇ of the obtained polyimide was 35,000, and the imidation ratio was 87%.
• This liquid crystal alignment agent was subjected to the same treatment as in Example 1 to produce a liquid crystal cell. Observation of the alignment state of the liquid crystal with a polarizing microscope confirmed that the liquid crystal had a uniform vertical alignment without any defects.
• the voltage holding ratio of this liquid crystal cell was evaluated in the same manner as in Example 1. As a result, the voltage holding ratio at 80 ° C before aging showed a very high value of 97.8%. Furthermore, the voltage holding ratio at 80 ° C after aging treatment at 120 ° C for one week maintained a very high value of 95.5%. In addition, when the alignment state of the liquid crystal after aging was observed with a polarizing microscope, it was confirmed that the liquid crystal had a uniform vertical alignment without any defect.
• Example 6 25 g of the liquid crystal alignment treatment agent prepared in Example 6, and a concentration of 6 wt% synthesized and prepared in Example 2. was mixed with 25 g of a polyamic acid solution of the above, and sufficiently stirred to obtain a liquid crystal orientation treating agent of the present invention as a uniform solution.
• a polyimide powder was obtained in the same manner as in Example 5, except that the imidization condition of the polyamic acid solution was changed from 30 ° C / 4 hours to 50 ° C / 4 hours.
• the weight average molecular weight ⁇ Mw ⁇ of the obtained polyimide was 35,000, and the imidation ratio was 97%.
• This liquid crystal alignment agent was subjected to the same treatment as in Example 1 to produce a liquid crystal cell. Observation of the alignment state of the liquid crystal with a polarizing microscope confirmed that the liquid crystal had a uniform vertical alignment without any defects.
• This liquid crystal alignment agent was subjected to the same treatment as in Example 1 to produce a liquid crystal cell. Observation of the alignment state of the liquid crystal with a polarizing microscope confirmed that the liquid crystal had a uniform vertical alignment without any defects.
• This liquid crystal alignment agent was subjected to the same treatment as in Example 1 to produce a liquid crystal cell. Observation of the alignment state of the liquid crystal with a polarizing microscope confirmed that the liquid crystal had a uniform vertical alignment without any defects.
• the voltage holding ratio of this liquid crystal cell was evaluated in the same manner as in Example 1. As a result, the voltage holding ratio at 80 ° C before aging was as high as 97.3%, but the voltage holding ratio at 80 ° C after aging at 120 ° C for 1 week was 87%. . 9%, which was lower than the initial level. When the alignment state of the liquid crystal after aging was observed with a polarizing microscope, it was confirmed that the liquid crystal had a uniform vertical alignment without any defect.

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• 2004
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