WO2005040274A1

WO2005040274A1 - Aligning agent for liquid crystal and liquid-crystal display element

Info

Publication number: WO2005040274A1
Application number: PCT/JP2004/015531
Authority: WO
Inventors: Tetsuya Imamura; Hideyuki Nawata; Rie Gunji
Original assignee: Nissan Chemical Industries, Ltd.
Priority date: 2003-10-23
Filing date: 2004-10-20
Publication date: 2005-05-06
Also published as: CN1845965A; JPWO2005040274A1; KR20060133528A; TWI374928B; JP4702058B2; CN100396728C; TW200523345A; KR101133479B1

Abstract

An aligning agent for liquid crystals which can form a liquid-crystal alignment film which enables a liquid crystal to change little in pretilt angle with changing ambient temperature and to stably have a large pretilt angle even at a high temperature; and a liquid-crystal display element which can stably display high-quality images even when the ambient temperature changes. The aligning agent for liquid crystals comprises an addition polymer having a structural unit represented by the following formula (1). The liquid-crystal display element is produced with the aligning agent for liquid crystals. (In the formula, A is a structure of the main chain of a polymer obtained by addition polymerization; B is a single bond or a bonding group selected from the group consisting of an ester, ether, amide, and urethane; X1 and X2 each independently represents an aromatic ring, aliphatic ring, or heterocycle; and R1 represents C3-18 alkyl, C3-18 alkoxy, C1-5 fluoroalkyl, C1-5 fluoroalkoxy, cyano, or halogeno.)

Description

Specification

Liquid crystal alignment agent and liquid crystal display device

Technical field

The present invention relates to a liquid crystal alignment treatment agent used for forming a liquid crystal alignment film of a liquid crystal display element, and a liquid crystal display element manufactured using the same.

Background art

[0002] At present, a liquid crystal display element that has become widespread has a structure in which a liquid crystal material is filled between two opposing substrates, and the liquid crystal material is formed by the action of a liquid crystal alignment film provided on the substrate surface. The desired initial alignment state is maintained. As the liquid crystal alignment film, a method of rubbing a polyimide resin film (rubbing film) is generally widely used. As an alternative to the rubbing film, a method of irradiating the organic film with polarized ultraviolet light (photo-alignment film) is also being vigorously studied.

[0003] It is generally known that the applied voltage-transmittance characteristic of such a liquid crystal display element fluctuates depending on the environmental temperature, and this is an obstacle to stable high-quality display. The first factor in which the characteristics fluctuate is that the characteristics of the liquid crystal have temperature dependence, but there is also a factor derived from the liquid crystal alignment film. For example, if the pretilt angle of the liquid crystal changes due to the environmental temperature, a shift occurs in the threshold voltage when driving the liquid crystal, and as a result, the applied voltage-transmittance characteristic of the liquid crystal display element also changes. The fluctuation of the pretilt angle due to the environmental temperature is remarkable when the liquid crystal alignment film has a weak liquid crystal alignment regulating force, such as a liquid crystal alignment film having a high pretilt angle or a photoalignment film. In extreme cases, the pretilt angle is greatly reduced at high temperatures, causing problems such as a failure to drive the liquid crystal normally. Therefore, a liquid crystal display element that requires a high pretilt angle and a method of replacing a rubbing film have attracted attention, and this is a particularly important problem for a photo-alignment film.

[0004] Usually, the pretilt angle of the liquid crystal obtained from a polyimide-based liquid crystal alignment film having a simple structure is not very high. is known a method of introducing an alkyl group or Furuoroarukiru group, Ru (for example, JP-2- 282726 discloses reference.) ₀ [0005] Further, with respect to the pretilt angle increased as described above, the stability to the temperature at which a liquid crystal alignment film is formed and the stability to heat treatment after forming a liquid crystal display element are improved by improving the side chain of polyimide. structures are also known techniques for introducing a cyclic substituent (e.g., JP-a 9 278 724 JP reference.) ₀

[0006] The pretilt angle stabilization technology, which has been proposed in the past, has almost the stability to the manufacturing process and the stability related to the durability. There are no reports on corner stabilization techniques.

Disclosure of the invention

Problems to be solved by the invention

The present invention has been made to solve the problem of the stability of the pretilt angle of a liquid crystal with respect to a change in environmental temperature, particularly, the stability of the pretilt angle at a high temperature. That is, an object of the present invention is to form a liquid crystal alignment film having a small change in pretilt angle with respect to a change in environmental temperature, a stable high liquid crystal even at high temperatures, and a pretilt angle. It is an object of the present invention to provide a liquid crystal display device capable of performing high-quality display stably with respect to a change in environmental temperature.

Means for solving the problem

[0008] It has been found that the above object of the present invention can be solved by the following liquid crystal alignment treatment agent and liquid crystal display element.

[0009] By all means, the present invention has the following gist.

1. A liquid crystal alignment treatment agent containing an addition polymer containing a structural unit represented by the following formula (1)

[0010] [Formula 1]

(In the formula, A is a main chain structure of a polymer obtained by addition polymerization, and B is a single bond or It is a bonding group selected from the group consisting of an ester, an ether, an amide, and a urethane. XI and X2 independently represent an aromatic ring, an aliphatic ring, or a heterocyclic ring, and R1 is an alkyl group having 3 to 18 carbon atoms, an alkoxy group having 3 to 18 carbon atoms, and a fluoroalkyl having 115 carbon atoms. Group, a fluoroalkoxy group having 115 carbon atoms, a cyano group, or a halogen atom. )

2. The liquid crystal alignment treatment agent according to 1 above, further comprising at least one polymer selected from the group consisting of polyamic acids, polyimides, polyamides, polyesters, and polyureas.

3. The liquid crystal alignment treatment as described in 2 above, wherein the addition polymer is contained in a state of being chemically bonded to at least one polymer selected from the group consisting of polyamic acid, polyimide, polyamide, polyester, and polyurea. Agent.

4. The method according to the above 2 or 3, wherein the weight ratio of the structural unit represented by the formula (1) is 0.01% to 50% by weight in the whole polymer component contained in the liquid crystal alignment treatment agent. Liquid crystal orientation agent.

5. The addition polymer contains at least 50% of the structural unit represented by the formula (1) in terms of the number of the structural units, and the ratio of the addition polymer to all polymer components is 0.1 to 20% by weight. %. The liquid crystal alignment treatment agent according to any one of items 1 to 4, above.

6. The liquid crystal alignment treatment agent according to any one of the above items 15 to 15, wherein the addition polymer contains 5% or more of the structural unit represented by the formula (1) in terms of the number of the structural units.

7. The liquid crystal alignment treatment agent according to any one of the above items 1 to 6, wherein the addition polymer has a structural unit represented by the following formula (2) in the structural unit represented by the formula (1): .

[Formula 2]

(In the formula, R2 represents a hydrogen atom, a methyl group, or a halogen atom.)

8. A liquid crystal display device using the liquid crystal alignment treatment agent according to any one of the above items 1 to 7. The invention's effect

[0012] The liquid crystal alignment film formed from the liquid crystal alignment agent of the present invention can provide a thermally stable high pretilt angle to a liquid crystal in which the change in the pretilt angle of the liquid crystal with respect to a change in environmental temperature is small. it can. In addition, the liquid crystal display device using the liquid crystal alignment agent of the present invention can perform stable and high-quality display with little change in applied voltage-transmittance characteristic with respect to changes in environmental temperature.

Brief Description of Drawings

FIG. 1 is a graph showing a VT curve of Example 1.

FIG. 2 is a graph showing a VT curve of Comparative Example 4.

Explanation of symbols

V: applied voltage (V) T: transmittance (%)

23 ° C: V-T curve at 23 ° C 60 ° C: V-T curve at 60 ° C

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail.

The liquid crystal alignment treating agent of the present invention is a coating solution for forming a liquid crystal alignment film on a substrate, and is an addition polymer containing a structural unit represented by the formula (1) as a stabilizer for imparting a pretilt angle of liquid crystal. It contains.

[0016] [Formula 3]

In the formula (1), A is a main chain structure of a polymer obtained by an addition polymerization reaction, and B is a single bond or a bonding group selected from the group consisting of ester, ether, amide, and urethane. Examples of the polymer obtained by the addition polymerization reaction include polybutyl, poly (meth) acrylic acid, and polymaleimide. Specific structural examples of the portion indicated by A are described below, but are not limited thereto. [0017] [Dani 4]

(In the above formula, R2 represents a hydrogen atom, a methyl group, or a halogen atom such as a fluorine atom or a chlorine atom.)

As a polymer obtained by the addition polymerization reaction, poly (meth) acrylic acid is preferred from the viewpoints of polymerizability and ease of side chain introduction. As a specific structure, a structure represented by the formula (2) in which the portion represented by AB in the formula (1) is preferable.

[0018] [Formula 5]

(In the formula, R2 represents a hydrogen atom, a methyl group, or a halogen atom such as a fluorine atom and a chlorine atom.)

In the formula (1), XI and X2 independently represent an aromatic ring, an aliphatic ring, or a hetero ring, and R 1 is an alkyl group having 3 to 18 carbon atoms, and an alkoxy group having 3 to 18 carbon atoms. A fluoroalkyl group having 115 carbon atoms, a fluoroalkoxy group having 115 carbon atoms, a cyano group, or a halogen atom. The portion composed of XI-X2-R1 preferably has a liquid crystal-like structure.

[0020] Specific examples of XI or X2 include the following. Aromatic rings include benzene, naphthalene, anthracene, phenanthrene, and indane rings, and aliphatic rings include cyclobutane, cyclopentane, cyclohexane, and bicyclooctane. Include a furan ring, a thiophene ring, a thiazole ring, a pyridine ring, a pyrimidine ring, Examples include a noline ring, an acylidine ring, a phenanthridine ring, a benzothiazole ring, and a dioxane ring. In the bonding position of these ring structures in the formula (1), a higher linearity is more preferable, for example, a benzene ring is preferably a para bond. Preferred examples of XI or X2 are shown below, but are not limited thereto. XI and X2 may have different structures.

[0021] [Formula 6]

[0022]

[0023]

In the above structure, any hydrogen atom on the ring structure may be substituted with a methyl group, an ethyl group, or a halogen atom such as a fluorine atom or a chlorine atom.

The combination of XI and X2 is more preferably a combination in which a group power consisting of a benzene ring, a cyclohexane ring, a pyridine ring, and a pyrimidine ring is also selected from the viewpoint of compatibility with the current liquid crystal. , Benzene ring, and cyclohexane ring force preferable. Specifically, the combination of XI and X2 is particularly preferably selected from the group consisting of biphenyl, bicyclohexyl, phenylcyclohexyl, and cyclohexylphenyl.

[0025] R1 is an alkyl group having 3 to 18 carbon atoms, an alkoxy group having 3 to 18 carbon atoms, or a fluorophore having 115 carbon atoms in accordance with the compatibility with the liquid crystal to be used and the desired pretilt angle. It can be appropriately selected from a alkyl group, a fluoroalkoxy group having 115 carbon atoms, a cyano group, and a halogen atom. Among them, an alkyl group having 5 to 8 carbon atoms and an alkoxy group having 5 to 8 carbon atoms are particularly preferable because of wide application range.

[0026] The following is a limited force showing a part of a specific example of the portion consisting of XI-X2-R1. In the following structure, n is preferably an integer of 3-12, particularly preferably 5-10.

[0027] [Formula 9]

[0028] [Formula 10]

[0029]

[0030] The addition polymer containing the structural unit represented by the formula (1) is a homopolymer of the structural unit represented by the formula (1) or a random copolymer with another structural unit obtained by addition polymerization. It may be any of a copolymer, an alternating copolymer, a block copolymer, or a graft copolymer. These polymers can be synthesized by known radical polymerization, cationic polymerization, ion polymerization and the like. The polymerization means may be any of thermal polymerization, photopolymerization and the like.

[0031] The addition polymer containing the structural unit represented by the formula (1) comprises the monomer corresponding to the formula (1), that is, the XI-X2-R1 via the bonding group represented by the B It can be obtained by a general addition polymerization reaction using a vinyl compound having a substituent, a maleimidized compound, or the like.

[0032] The structure of a monomer corresponding to the structure represented by the formula (1) is shown below, but is not limited thereto. Note that Rl, R2, XI, and X2 in the following formula are as described above. [0033] [Formula 12]

[0034] [Formula 13]

[0035]

[0036] [Formula 15]

[0037] [Formula 16]

HN— X1— X2 [0038] [Formula 17]

[0039] [Formula 18]

[0040] One or more of the above monomers may be used in combination. In addition, the polymer having the structure represented by the formula (1) controls the magnitude of the pretilt angle, controls the solubility of the polymer in an organic solvent, and the other polymer contained in the liquid crystal alignment treatment agent. For the purpose of controlling the compatibility of the liquid crystal, improving the applicability of the liquid crystal alignment agent, and imparting heat resistance to the liquid crystal alignment film, a random copolymer, It can be an alternating copolymer, a block copolymer or the like.

[0041] Specific examples of other monomers capable of undergoing an addition polymerization reaction include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, Hexyl (meth) acrylate, hydroxyethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyhexyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, (meth) acrylic acid Cyclohexyl, (meth) acrylate, benzyl (meth) acrylate, glycidyl (meth) acrylate, styrene, hydroxystyrene, carboxystyrene, methacrylamide, N-aryl methacrylamide, N-hydroxyethyl N-methyl methacrylamide, N-methyl-N-methyl methacrylamide, acrylamide , N- § reel acrylamide, N, N- § reel acrylamide, N- methyl-N Hue - Le acrylamide, N Bulle Examples thereof include 2-pyrrolidone, N-phenylmaleimide, bulcarbazole, bulpyridine, and biluimidazole. Of these, glycidyl methacrylate is particularly preferred because it has an effect on improving the solubility and compatibility of the polymer.

As described above, using the monomer corresponding to the structure represented by the formula (1) and, if necessary, other monomer components capable of undergoing an addition polymerization reaction, the formula (1) An example of a method for obtaining an addition polymer containing the structural unit shown by a radical polymerization method is described below. Dissolve the corresponding monomer in an organic solvent and add a reaction initiator. The solvent for the above reaction is not particularly limited as long as it can dissolve the obtained polymer. For example, γ-petit mouth ratataton, cyclohexanone, dimethyl sulfoxide, Ν-methyl-2-pyrrolidone, Ν, Ν-dimethylacetoamide, Ν, Ν-dimethylformamide, ethyl lactate (EL), methoxypropanol (PG ME), propylene Glycol monomethyl ether acetate (PGMEA), or a mixture thereof. Examples of the reaction initiator include azoi conjugates such as AIBN (azobis isopuchi mouth-tolyl), and peroxy sulfides such as peroxy benzoyl. The reaction system may be heated for the purpose of promoting the reaction or completing the reaction. The polymer obtained in this manner may be used in a poor solvent in which the reaction solution can be used as it is, and the target polymer may be recovered to use the force.

[0043] In the addition polymer containing the structural unit represented by the formula (1), the content ratio of the structural unit represented by the formula (1) is a force that can be freely set. Therefore, the content is preferably 5% or more in terms of the number of structural units, more preferably 30% or more. As described later, when the liquid crystal alignment treatment agent of the present invention contains an addition polymer containing the structural unit represented by the formula (1) and a polymer other than the polymer, the formula (1) The content ratio of the structural unit represented by is preferably 50% or more, more preferably 60% or more, and particularly preferably 70% or more.

[0044] The molecular weight of the polymer having the structure represented by the formula (1) is not particularly limited !, but is, for example, 1000 to 1,000,000, 2000 to 2000, as a weight average molecular weight measured by a GPC (Gel Permeation Chromatography) method. Suitable for a force such as 400,000, 5000 to 100,000.

[0045] The polymer component contained in the liquid crystal alignment treatment agent of the present invention is, in addition to the addition polymer containing the structural unit represented by the formula (1), for controlling the liquid crystal alignment in the horizontal direction with respect to the substrate. It is preferable to include a polymer. As such a polymer, a polymer used for a general liquid crystal alignment film can be used, and polyamic acid, polyimide, polyamide, polyester, polyurea and the like are preferable. In particular, polyamic acid or polyimide is excellent in liquid crystal alignment and heat resistance, is widely used as a material for a liquid crystal alignment film, and is preferably used as a polymer component contained in the liquid crystal alignment treatment agent of the present invention.

The structure of the above-mentioned polyamic acid or polyimide is not particularly limited. However, when the liquid crystal alignment treatment agent of the present invention is used in a method of irradiating polarized ultraviolet light or the like to form a liquid crystal alignment film, that is, a so-called light alignment film It is desirable that the main chain contains a cyclobutane ring, an amide bond, an olefin structure, and a benzophenone structure that chemically react with light.

[0047] In general, polyamic acid can be obtained by reacting tetracarboxylic dianhydride with diamine conjugate in an organic solvent. Further, polyimide can be obtained by imidizing (dehydrating and cyclizing) polyamic acid.

[0048] Examples of the polyamic acid that can be contained in the liquid crystal alignment treatment agent of the present invention include one or more tetracarboxylic dianhydrides selected from the following tetracarboxylic dianhydrides and diamine conjugates. Examples include, but are not limited to, polyamic acids obtained by reacting an anhydride with one or more diamine compounds.

[0049] Examples of the tetracarboxylic dianhydride used in the polyamic acid synthesis reaction include pyromellitic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 1,2,5,6-naphthalenetetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid, 2,3,6,7-anthracenetetracarboxylic acid, 1,2,5,6-anthracenetetracarboxylic acid, 3,3,4,4,4-biphene- Rutetracarbonic acid, 2,3,3,4-biphenyltetracarboxylic acid, bis (3,4-dicarboxyphenyl) ether, 3,3,4,4,1-benzophenonetetracarboxylic acid, 3,3,4,4,1-chalconetetracarboxylic acid, bis (3,4-dicarboxyphenyl) sulfone, bis (3,4-dicarboxyphenyl) methane, 2,2-bis (3,4-di Carboxyphenyl) propane, 1,1,1,3,3,3-hexafluoro-2,2-bis (3,4-di Ruboxyphenyl) propane, bis (3,4-dicarboxyl) dimethylsilane, bis (3,4-dicarboxyphenyl) diphenylsilane, 2,3,4,5-pyridinetetracarboxylic acid, 2,6-bis (3,4-dicarboxyphenyl) dianhydride of aromatic tetracarboxylic acid such as pyridine, 1,2,3,4-cyclobutanetetraforce Rubonic acid, 1,2,3,4-cyclopentanetetracarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid, 2,3,5-tricarboxycyclopentylacetic acid, 3,4-dicarboxy-1, 2,3,4-tetrahydro-1 dihydrate of alicyclic tetracarboxylic acid such as naphthalene succinic acid, dianhydride of aliphatic tetracarboxylic acid such as 1,2,3,4 butanetetracarboxylic acid, etc. .

The diamine compounds used in the polyamic acid synthesis reaction include p-diene diamine, m-phenylene diamine, N, N-diaryl 1,2,4 benzenetriamine, 2,5-diaminobenzonitrile, and 2,5-diaminotoluene. , 2,6-diaminotoluene, 4,4'diaminobiphenyl, 3,3, -dimethyl-4,4-diaminobiphenyl, 3,3, dimethoxy-4,4, -diaminobiphenyl, diaminodiphenylmethane, diaminodiphenyl -Diether, diaminodiphenylamine, 2,2, diaminodiphenylpropane, bis (3,5-diethyl-4-aminophenyl) methane, diaminodiphenylsulfone, diaminobenzophenone, 3,3'-diaminochalcone, 4,4, Diaminochalcone, 3, 3, diaminostilbene, 4, 4, diaminostilbene, diaminonaphthalene, 1, 4 1,4-bis (4-aminophenyl) benzene, 9,10 bis (4-aminophenyl) anthracene, 1,3 bis (4-aminophenoxy) benzene, 4,4'bis (4aminophenoxy) diphenyl sulfone, 2,2-bis [4- (4aminophenoxy) phenyl] propane, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2bis [4— Aromatic diamines such as (4aminophenoxy) phenyl] hexafluoropropane, 2,6-diaminopyridine, 2,4-diaminopyridine, 2,7-diaminobenzofuran, 2,7-diaminocarbazole, 3, Heterocyclic diamines such as 7-diaminophenothiazine, 2,5-diamino-1,3,4-thiadiazole, 2,4-diamino-s-triazine, bis (4-aminocyclohexyl) methane, Screw (4 Alicyclic diamines such as mino-3-methylcyclohexyl) methane and aliphatic diamines such as 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane and 1,6-diaminohexane; 1,3-diamino-4 year old Kuta decyloxybenzene, 1,3-diamino-4-1, hexadecyloxybenzene, 1,3-diamino 4-dodecyloxybenzene, 4- [4— (4— Trans-n-heptylcyclohexyl) phenoxy] -1,3-diaminobenzene, (4-trans-n-pentylbicyclohexyl) -1,3,5-diaminobenzoate, etc. And silicon diamines such as 1,1,3-bis (3-aminopropyl) -1,1,3,3-tetramethyldisiloxane.

[0051] The polyamic acid contained in the liquid crystal alignment agent of the present invention preferably has a weight average molecular weight {Mw} of 21,500,000 as measured by GPC (Gel Permeation Chromatography). 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 during the formation of the coating film may deteriorate. The molecular weight of the polyamic acid can be controlled by adjusting the molar ratio of the tetracarboxylic dianhydride and the diamine conjugate used in the polyamic acid synthesis reaction. As in the ordinary polycondensation reaction, the closer the mole ratio is to 1.0, the higher the degree of polymerization of the produced polymer becomes.

[0052] The polyamic acid synthesis reaction is carried out in an organic solvent at a reaction temperature of usually 0 to 150 ° C, preferably 0 to 100 ° C. The organic solvent at this time is not particularly limited as long as the obtained polyamic acid can be dissolved. Specific examples include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, dimethylsulfoxide, tetramethylurea, pyridine, dimethyl Sulfone, hexamethylsulfoxide, γ-butyrolataton and the like can be mentioned. These may be used alone or as a mixture. Further, even if the solvent does not dissolve the polyamic acid, it may be used by mixing with the above solvent as long as the polyamic acid generated by the polymerization reaction does not precipitate.

Examples of the polyimide that can be contained in the liquid crystal alignment treatment agent of the present invention include those obtained by subjecting the above-mentioned polyamic acid to imidization (dehydration ring closure). Here, the polyimide is included in its category even if all of the repeating units of the polyamic acid are not imidized, and is suitably used for the liquid crystal alignment treatment agent of the present invention.

[0054] Usually, the imidization (dehydration ring closure) of the polyamic acid can be performed in a solution. In the method of imidizing a polyamic acid 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 closure reaction does not proceed sufficiently, and if the reaction temperature exceeds 200 ° C, the molecular weight of the obtained imidized polymer may decrease. Addition of a dehydrating agent and a dehydration ring-closing catalyst during this imidization reaction is advantageous because the imidation reaction proceeds at a relatively low temperature and the resulting polyimide is less likely to have a reduced molecular weight. preferable. As the dehydrating agent, for example, tertiary amines such as pyridine and triethylamine can be used. The amount of the dehydrating agent used is preferably 0.01 to 20 mol per 1 mol of the repeating unit of the polyamic acid. As the dehydration ring-closing catalyst, for example, tertiary amines such as pyridine and triethylamine can be used. The amount of the dehydration ring-closing catalyst used is preferably 0.01 to 10 mol per 1 mol of the dehydrating agent used. Examples of the organic solvent used for the dehydration ring closure reaction include the organic solvents exemplified as those used for the synthesis of polyamic acid. The reaction temperature when the dehydrating agent and the dehydration ring-closing catalyst are added is usually 0 to 180 ° C, preferably 10 to 150 ° C.

The polyamic acid or polyimide obtained as described above may be used as it is, or may be used after precipitation and isolation in a poor solvent such as methanol or ethanol.

[0056] In the liquid crystal alignment treatment agent of the present invention, the addition polymer containing the structural unit represented by the formula (1) is contained in a form chemically bonded to a polymer contained as another polymer component. You may. As a method for this, for example, a substituent capable of addition polymerization is introduced into a side chain of a polymer contained as another polymer component, and in a solution in which this polymer is present, as described above, the formula (1) is used. An addition polymerization reaction may be carried out using a monomer corresponding to the structure shown and, if necessary, other monomer components capable of undergoing an addition polymerization reaction. In order to obtain a form in which a polymer having the structure represented by the formula (1) is chemically bonded to a polyamic acid or a polyimide, for example, a diamine having a butyl group and a methacryloyl group in a side chain is used. The synthesis may be performed, and the above reaction may be performed in a solution containing the polyamic acid.

Examples of the diamine having a methacryloyl group in a side chain include the following diamines. [0057] [Formula 19]

In addition, a polymer containing a hydroxy group, a carboxyl group, an amino group, an isocyanate group, an acid anhydride group, etc. as a polymer having a structure represented by the formula (1) and other polymer components And bonded by a reaction between a hydroxy group or a carboxyl group and an isocyanate group, or a reaction between an amino group and an acid anhydride group.

[0059] The weight ratio of the structural unit represented by the formula (1) in the entire polymer component contained in the liquid crystal alignment treatment agent of the present invention is arbitrarily determined according to the desired pretilt angle. It can be set, but the weight ratio is preferably 0.01 to 50% by weight, more preferably 0.1 to 20% by weight.

Further, the liquid crystal alignment treatment agent of the present invention includes an addition polymer containing the structural unit represented by the formula (1), and a polymer for imparting horizontal liquid crystal alignment control to the substrate. In the case where is contained, the content ratio of the addition polymer containing the structural unit represented by the formula (1) may be 0.1 to 20% by weight of the whole polymer component contained in the liquid crystal alignment treatment agent. It is more preferably 0.3-5% by weight. By adding a relatively small amount of the addition polymer having a high content of the structural unit represented by the formula (1) to the polymer for controlling the liquid crystal alignment in the horizontal direction with respect to the substrate, the pretilt angle can be reduced. It is possible to obtain a liquid crystal alignment film that is stable and excellent in regulating the liquid crystal alignment in the horizontal direction with respect to the substrate.

From the above, it is preferable that the composition of the polymer component contained in the liquid crystal alignment treatment agent of the present invention be, for example, (A) the content ratio of the structural unit represented by the formula (1) is The addition polymer is at least 50%, more preferably at least 60%, particularly preferably at least 70% in terms of the number of units, and at least one type selected from (B) polyamic acid, polyimide, polyamide, polyester or polyester. polymers and contain a ratio of (a) in the total polymer component 0.5 1 20 weight ^_0/0, a composition more preferably from 0.5 3 5 wt%. [0062] The liquid crystal alignment treatment agent of the present invention is a coating solution containing the above-described polymer component. The solvent contained in the coating solution is not particularly limited as long as it can dissolve the polymer component. These can be used alone or in combination of two or more solvents. Furthermore, even if it is a solvent which does not dissolve the polymer by itself, it can be added within a range in which the polymer component does not precipitate. Specific examples of the solvent component are shown below, but are not limited thereto.

[0063] N-methyl-2-pyrrolidone, Ν, Ν-dimethylformamide, Ν, Ν-dimethylacetamide, γ-butyrolataton, dimethylsulfoxide, tetramethylurea, hexamethylphosphotriamide, m-creso-monole, methinole Anoreconore, etinoleanorekonore, echinoreenotenore, ethylenglycorenomonomethinooleatenore, ethylene glycolonorenotenore, ethylene glycoloneole _n- butinoreatenore, ethyleneglycorerenotenore Athenole, diethylene glycol dimethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, cyclohexanone, hexane, heptane, toluene, xylene.

[0064] The liquid crystal alignment treatment agent of the present invention may contain a functional silane-containing compound for imparting adhesion to a substrate. For example, N-trimethylsilylacetamide, diacetoxydimethylsilane, tetramethoxysilane, 3-aminopropyljetoxymethylsilane, 3-aminopropyltriethoxysilane, 1,4-bis (dimethylsilyl) benzene, bis (dimethylamino) dimethyl Examples include silane, bis (ethylamino) dimethylsilane, 1-trimethylsilylimidazole, methyltriacetoxysilane, ethoxymethylphenylsilane, phenyltriethoxysilane, and diphenylsilanediol. ,.

[0065] In order to obtain the liquid crystal alignment treatment agent of the present invention, the above-mentioned components are mixed to form a solution having a concentration capable of being applied to a substrate. The concentration of the polymer component in the liquid crystal alignment treatment agent of the present invention can be appropriately changed depending on the setting of the thickness of the liquid crystal alignment film to be formed, but is preferably set to be 11 to 15% by weight. If it is less than 1% by weight, it is difficult to form a uniform and defect-free coating film, and if it is more than 15% by weight, the storage stability of the solution may be poor.

[0066] The liquid crystal alignment treating agent of the present invention obtained as described above is filtered, if necessary, It can be applied to a substrate, dried and fired to form a coating film. By subjecting the coating surface to rubbing or irradiating polarized ultraviolet light in a certain direction to the substrate surface, the liquid crystal It can be used as an alignment film.

[0067] As a method for applying the liquid crystal alignment treatment agent, a transfer printing method is widely used industrially from the viewpoint of productivity S such as a spin coating method, a printing method, an ink jet method, and productivity. It is also suitably used in the liquid crystal aligning agent of the present invention.

[0068] The step of drying after applying the liquid crystal alignment treatment agent is not necessarily required. However, when the time from application to one baking is not constant for each substrate, or when baking is not performed immediately after application. Preferably includes a drying step. The drying method 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 transfer of the substrate or the like. As a specific example, 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.

[0069] The firing of the liquid crystal alignment treatment agent can be performed at any temperature of 100 to 350 ° C, preferably 150 to 300 ° C, and more preferably 200 to 250 ° C. is there. When a polyamic acid is contained in the liquid crystal alignment treatment agent, the conversion to polyamic acid force polyimide changes depending on the firing temperature.However, the liquid crystal alignment treatment agent of the present invention does not necessarily need to be imidized 100%. There is no. However, it is preferable to perform firing at a temperature that is at least 10 ° C. higher than the heat treatment temperature required for the liquid crystal cell manufacturing process, such as curing of a sealant.

[0070] The thickness of the coating film after firing is too large, which is disadvantageous in terms of power consumption of the liquid crystal display element, and too thin, the reliability of the liquid crystal display element may be reduced. Is 10—100 nm.

[0071] The liquid crystal display element of the present invention is obtained by obtaining a substrate with a liquid crystal alignment film from the liquid crystal alignment treatment 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 element. It is. To give an example of liquid crystal cell production, a pair of substrates on which a liquid crystal alignment film is formed is sandwiched between spacers of 110 μm, preferably 2 to 10 μm, with a rubbing direction of 0 to 270 μm. It is a common practice to install the device at an arbitrary angle, fix the periphery with a sealant, and inject and seal liquid crystal. The method of sealing the liquid crystal is not particularly limited. The vacuum method in which the pressure in the manufactured liquid crystal cell is reduced and then the liquid crystal is injected, and the sealing after the liquid crystal is dropped. Examples of the method include a dropping method.

[0072] 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. It is also preferable to use a substrate on which electrodes and the like are formed from the viewpoint of simplifying the process. In the case of a reflection type liquid crystal display element, an opaque object 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.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

Example

5.16 g (49.36 mmol) of methacryloyl chloride, 11.06 g (44.87 mmol) of 4- (4-trans-n-pentylcyclohexyl) phenol, and 4.99 g (49.36 mmol) of triethylamine in 200 mL of tetrahydrofuran solvent, The mixture was stirred at room temperature for 30 minutes, and then at 50 ° C for 1 hour. The reaction solution was gradually cooled to room temperature, extracted with ethyl acetate, and the organic layer was dried over anhydrous sodium sulfate. After concentrating the organic layer, the residue is purified by silica gel column chromatography (ethyl acetate: hexane = 3: 1), and 4 (4-trans-n-pentylcyclohexyl) phenoxymethatalate having an HPLC relative purity of 99% or more is obtained. 14.15 g was obtained.

20.10 g (0.07 mol) of 4 (4 trans-n-pentylcyclohexyl) phenoxymethallate and 4.27 g (0.03 mol) of glycidyl methacrylate obtained in the same manner as in Synthesis Example 1 were added to N-methyl- 2 Pyrrolidone (hereinafter abbreviated as NMP) After dissolving in 87.48 g, the inside of the flask was replaced with nitrogen and the temperature was raised to 70 ° C. After the temperature was raised, 0.2 g of azoisobutyl mouth-tolyl (hereinafter abbreviated as AIBN) dissolved in NMPlOg was added under a nitrogen-added atmosphere and reacted for 24 hours to obtain an addition polymer containing a structural unit of the formula (1). . The weight average molecular weight {Mw} of this addition polymer was 28,000.

Dissolve 10.81 g (0.1 mol) of p-phenylenediamine in 172.4 g of NMP and add 19.61 g (0.1 mol) of butanetetracarboxylic dianhydride was added, and the mixture was reacted at room temperature for 24 hours to obtain a polyamic acid. The weight average molecular weight {Mw} of the obtained polyamic acid was 156000.

NMP was added to the reaction solution of the addition polymer obtained in Synthesis Example 2 to obtain a solution having an addition polymer concentration of 3 wt%. NMP was added to the polyamic acid reaction solution obtained in Synthesis Example 3 to obtain a polyamic acid concentration of 3 wt%. To 99 g of this 3 wt% solution of polyamic acid, 1 g of a 3 wt% solution of the addition polymer was added, and the mixture was sufficiently stirred to obtain a uniform solution, thereby obtaining a liquid crystal alignment treating agent of the present invention.

This liquid crystal alignment treatment agent was subjected to pressure filtration with a membrane filter having a pore size of 0.5 μm, and then spin-coated on a glass substrate with a transparent electrode. The substrate was dried on a hot plate at 80 ° C for 5 minutes, and then baked in a hot air circulating oven at 210 ° C for 60 minutes to obtain a 50 nm-thick coating film on the substrate. The coated surface was subjected to a rubbing treatment using a rubbing device equipped with rayon cloth under the conditions of a rotational speed of 300 rpm, a moving speed of 20 mmZs, and an indentation of 0.5 mm to obtain a substrate with a liquid crystal alignment film.

[0078] Two substrates having the above-mentioned liquid crystal alignment film were prepared, and a 6-μm spacer was sprayed on the liquid crystal alignment film surface of one of the substrates. Then, the substrates were laminated so that the rubbing direction was perpendicular to the substrate. A liquid crystal cell was prepared by injecting ZLI-4792 from Merck. This liquid crystal cell was treated at 120 ° C. for 30 minutes, and the alignment state of the liquid crystal after that was observed with a polarizing microscope. As a result, it was confirmed that V ヽ uniform alignment without defects was obtained.

[0079] The pretilt angle of this liquid crystal cell at 23 ° C was measured to 22.1 ° using a pretilt angle measuring device (PAS-301) manufactured by ELSICON. Next, the voltage-transmittance characteristic (V-T curve) of this liquid crystal cell was measured at 23 ° C and 60 ° C, and the applied voltage (V90) at which the transmittance became 90% was measured. The thermal stability was evaluated by comparing the values of. As a result, 23. V90 in C is 0.72V, 60. The V90 at C was 0.66 V, and although a shift to the low voltage side due to the temperature characteristics of the liquid crystal was observed, no shift to the high voltage side due to the decrease in the pretilt angle was observed. Regardless, it was confirmed to have a very stable pretilt angle. [0080] The measurement of the VT curve and the calculation of V90 were performed as follows.

(1) Using a polarizing microscope with a light-receiving element installed in the eyepiece, the angle between the polarizer and analyzer of the polarizing microscope was set to 90 degrees.

(2) The liquid crystal cell was installed so that the alignment processing directions of the upper and lower substrates matched the polarization directions of the polarizer and the analyzer, respectively, so that the amount of light transmission was maximized when no voltage was applied. .

(3) A 30 Hz alternating-current rectangular wave was applied to the liquid crystal cell in the range of 0- ± 5 V in increments of 0.01 V, and the amount of light transmitted at that time was detected and recorded by the light receiving element.

(4) Assuming that the amount of transmitted light when no voltage is applied is 100% and the amount of transmitted light when 5V is applied is 0%, the relationship between applied voltage and transmittance is graphed.From this graph, the transmittance is 90%. The value of the applied voltage at the time of was read as V90.

(5) The measurement at 23 ° C was performed at room temperature of 23 ° C, and the measurement at 60 ° C was performed by heating the liquid crystal cell to 60 ° C on a stage of a polarizing microscope.

Instead of rubbing the coating film obtained in the same manner as in Example 1, using a light irradiation device manufactured by ELSICON, OptoAlign ™ (E3—UV—600—A), setting the angle of the lamp to Odeg and the irradiation amount to 20 J And a substrate with a liquid crystal alignment film was obtained by photo alignment treatment.

[0082] Two substrates with a liquid crystal alignment film were prepared, and a 6-μm spacer was sprayed on the liquid crystal alignment film surface of one of the substrates. Liquid crystal (ZLI-4792, manufactured by Merck) was injected to form a liquid crystal cell. This liquid crystal cell was treated at 120 ° C. for 30 minutes, and then the alignment state of the liquid crystal was observed with a polarizing microscope. As a result, it was confirmed that there was no defect and uniform alignment was obtained.

[0083] The pretilt angle and the VT curve of this liquid crystal cell were measured in the same manner as in Example 1. As a result, the pretilt angle was 22.5 °. The V90 at 23 ° C was 0.78 V, and the V90 at 60 ° C was 0.66 V. Although a shift to a lower voltage side due to the temperature characteristics of the liquid crystal was observed, it was due to a decrease in the pretilt angle. No shift to the high voltage side is observed, and it is confirmed that the pretilt angle has a very stable irrespective of the ambient temperature. <Comparative Example 1>

9.73 g (0.9 mol) of p-phenylenediamine and 3.77 g (0.1 mol) of 1,3-diamino-4 1-year-old octadecyloxybenzene were dissolved in 187.8 g of N-methylpyrrolidone (NMP), and cyclobutane was added thereto. 19.61 g (0. Imol) of tetracarboxylic dianhydride was added, and the mixture was reacted at room temperature for 24 hours to obtain a polyamic acid. The weight average molecular weight {Mw} of the obtained polyamic acid was 126 000. NMP was added to this polyamic acid reaction solution to prepare a solution having a concentration of 3 wt%, which was used as a liquid crystal alignment treatment agent for comparison.

[0085] A liquid crystal cell was produced in the same manner as in Example 1 using the above liquid crystal alignment treatment agent. Observation of the alignment state of the liquid crystal cell with a polarizing microscope confirmed that the liquid crystal cell had a uniform alignment without defects.

[0086] The pretilt angle and the VT curve of this liquid crystal cell were measured in the same manner as in Example 1. As a result, the pretilt angle was 16.5 °. The V90 at 23 ° C was 0.87 V, the V90 at 60 ° C was 1.01 V, and a shift to a high voltage side due to a decrease in the pretilt angle was observed at 60 ° C. It was unstable.

9.73 g (0.09 mol) of p-phenylenediamine and 3.81 g (0. Olmol) of 4- [4- (4-trans-n-butylcyclohexyl) phenoxy] -1,3-diaminobenzene are added to N-methylbi The solution was dissolved in 187.8 g of lidone (NMP), and 19.61 g (0.1 mol) of cyclobutanetetracarboxylic dianhydride was added thereto and reacted at room temperature for 24 hours to obtain a polyamic acid. The weight average molecular weight {Mw} of the obtained polyamic acid was 143,000. NMP was added to the polyamic acid reaction solution to make a solution having a concentration of 3 wt%, which was used as a liquid crystal alignment treatment agent for comparison.

A liquid crystal cell was produced in the same manner as in Example 1 using the above-mentioned liquid crystal alignment treatment agent. Observation of the alignment state of the liquid crystal cell with a polarizing microscope confirmed that the liquid crystal cell had a uniform alignment without defects.

[0089] The pretilt angle and the VT curve of this liquid crystal cell were measured in the same manner as in Example 1. As a result, the pretilt angle was 20.9 °. The V90 at 23 ° C was 0.63 V, the V90 at 60 ° C was 0.76 V, and a shift to a high voltage side due to a decrease in the pretilt angle was observed at 60 ° C. It was unstable. <Comparative Example 3>

After dissolving 12.72 g (0.05 mol) of n-dodecyl methacrylate and 7.11 lg (0.05 mol) of glycidyl methacrylate in 69.3 g of NMP, the atmosphere in the flask was replaced with nitrogen and the temperature was reduced to 70 ° C. The temperature rose. After the temperature was raised, 0.2 g of azoisobutyrate-tolyl (AIBN) dissolved in NMPlOg was added under a nitrogen atmosphere and allowed to react for 24 hours to obtain an addition polymer for comparison. The weight average molecular weight {Mw} of this addition polymer was 32,000.

[0091] p-Phenylenediamine 8.65 g (0.8 mol) and 4-—4- (4-trans n-butylsilyl hexyl) phenoxy] -1,3-diaminobenzene 7.61 g (0.2 mol) with N— It was dissolved in 203.3 g of methylpyrrolidone (NMP), and 19.61 g (0.1 mol) of cyclobutanetetracarboxylic dianhydride was added thereto and reacted at room temperature for 24 hours to obtain a polyamic acid. The weight average molecular weight {Mw} of the obtained polyamic acid was 143,000.

[0092] NMP was added to the reaction solution of the addition polymer obtained above to obtain a solution having an addition polymer concentration of 3 wt%. NMP was added to the polyamic acid reaction solution obtained above to obtain a solution having a polyamic acid concentration of 3% by weight. A 3 wt% solution lg of the above-mentioned addition polymer was added to 99 g of a 3 wt% solution of the polyamic acid, and the mixture was sufficiently stirred to obtain a uniform solution, thereby obtaining a liquid crystal alignment treatment agent for comparison.

[0093] A liquid crystal cell was produced in the same manner as in Example 2 using the above liquid crystal alignment agent. Observation of the alignment state of the liquid crystal cell with a polarizing microscope confirmed that the liquid crystal cell had a uniform alignment without defects.

The pretilt angle and the VT curve of this liquid crystal cell were measured in the same manner as in Example 1. As a result, the pretilt angle was 22.1 °. The V90 at 23 ° C was 0.70 V, and the V90 at 60 ° C was 1.28 V. At 60 ° C, a large shift to the high voltage side due to the decrease in pretilt angle was observed, and the pretilt angle Was very unstable.

[0095] <Comparative Example 4>

A 3 wt% solution of polyamic acid prepared in Comparative Example 3 was used as a liquid crystal alignment treatment agent for comparison.

Using this liquid crystal alignment agent, a liquid crystal cell was produced in the same manner as in Example 2. Observation of the orientation of the liquid crystal cell with a polarizing microscope revealed that the cell was uniform with no defects. Was confirmed.

The pretilt angle and the VT curve of this liquid crystal cell were measured in the same manner as in Example 1. As a result, the pretilt angle was 15.9 °. The V90 at 23 ° C is 0.78 V, the V90 at 60 ° C is 1.42 V, and a large shift toward high voltage due to the decrease in pretilt angle is observed at 60 ° C. Very unstable.

[0097] <Comparative Example 5>

A 3 wt% solution of polyamic acid prepared in Example 1 was used as a liquid crystal alignment treatment agent for comparison.

Using this liquid crystal alignment agent, a liquid crystal cell was produced in the same manner as in Example 2. Observation of the orientation of the liquid crystal cell with a polarizing microscope confirmed that the liquid crystal cell had a uniform orientation without defects.

[0098] The pretilt angle and the VT curve of this liquid crystal cell were measured in the same manner as in Example 1. As a result, the pretilt angle was as low as 0.3 °. The V90 at 23 ° C was 1.41 V, and the V90 at 60 ° C was 1.33 V. A shift toward a lower voltage due to the temperature characteristics of the liquid crystal was observed. This means that the pretilt angle almost appeared at 23 ° C, and therefore, even when the temperature was raised to 60 ° C, a decrease in the pretilt angle was not observed.

[Table 1] Orientation V90 value at pretilt angle 23 V90 value at 60: V90 value (23; _60Τ :) Example 1 Good 22.1 ° 0.72 V 0.66 V 0 . 06 V example 2 good 22. 5 ° 0. 78 V 0. 66 V 0. 12 V Comparative example 1 good ^{16. 5 0 0. 87 V 1. 0} 1 V one 0. 14 V Comparative example 2 good 20 9 ° 0.63 V 0.76 V – 0.13 V Comparative Example 3 Good 22.1 ° 0.70 V 1.28 V-0.58 V Comparative Example 4 Good 15.9. 0.78 V 1.42 V — 0.64 V Comparative Example 5 Good 0.3 ° 1.41 V 1.33 V 0.08 V

Claims

Claims [1] A liquid crystal alignment treating agent containing an addition polymer containing a structural unit represented by the following formula (1).

[Chemical 1]

(In the formula, A is a main chain structure of a polymer obtained by addition polymerization, B is a single bond or a bonding group selected from the group consisting of ester, ether, amide, and urethane. XI and X 2 are Independently represents an aromatic ring, an aliphatic ring, or a hetero ring, wherein R1 is an alkyl group having 3 to 18 carbon atoms, an alkoxy group having 3 to 18 carbon atoms, a fluoroalkyl group having 15 to 15 carbon atoms, Represents 1 to 5 fluoroalkoxy groups, cyano groups, or halogen atoms.)

2. The liquid crystal alignment treatment agent according to claim 1, further comprising at least one polymer selected from the group consisting of polyamic acids, polyimides, polyamides, polyesters, and polyureas.

3. The liquid crystal according to claim 2, wherein the addition polymer is contained in a state of being chemically bonded to at least one polymer selected from the group consisting of polyamic acid, polyimide, polyamide, polyester, and polyurea. Alignment agent.

[4] The weight ratio of the structural unit represented by the formula (1) in the entire polymer component contained in the liquid crystal alignment treatment agent is 0.01% to 50% by weight. The liquid crystal orientation treating agent according to the above.

[5] The addition polymer contains the structural unit represented by the formula (1) in an amount of 50% or more in terms of the number of structural units, and the ratio of the addition polymer to all polymer components is 0.1 to 20. The liquid crystal alignment treating agent according to any one of claims 14 to 14, which is% by weight.

6. The liquid crystal alignment treating agent according to claim 15, wherein the addition polymer contains 5% or more of the structural unit represented by the formula (1) in terms of the number of structural units.

[7] In the addition polymer, in the formula (1) of the structural unit, a portion represented by AB is represented by the following formula (

17. The liquid crystal alignment treatment agent according to claim 16, having a structure represented by 2). [Chemical 2]

[8] A liquid crystal display device using the liquid crystal alignment treatment agent according to claim 17.