KR101059138B1 - Photoaligning agent, a liquid crystal aligning film, the liquid crystal display element using this, and the manufacturing method of a liquid crystal aligning film - Google Patents

Abstract

[OBJECT] An object of the present invention is to provide an alignment film having particularly good orientation and low coloring.

[Solution] A photoalignment agent containing at least one of the polymers having the photo-alignment ability as the A component, and containing at least one of the polymers having the liquid crystal temperature range in the range of 100 to 300 ° C as the B component. Preferred examples of the component A are polyamic acids or polyimides having at least one photoreceptor represented by formulas (I) to (V) and formula (X) in the main chain, and a preferred example of the component B is 6 to 6 carbon atoms in the main chain. Liquid crystalline polyamic acid or polyimide having a straight chain alkylene structure of 20. R ¹ , R ² and R ³ are aromatic divalent groups.

Photoaligning agent, alignment film, liquid crystal display element, pretilt angle, ion density, polyamic acid

Description

Photoaligning agent, a liquid crystal aligning film, the liquid crystal display element using this, and the manufacturing method of a liquid crystal aligning film {PHOTO-ALIGNMENT MATERIAL, ALIGNMENT LAYER AND LIQUID CRYSTAL DISPLAY DEVICE COMPRISING THIS}

The present invention relates to an alignment film, a method for producing the same, and a liquid crystal display device having the alignment film.

Liquid crystal display elements are used in various liquid crystal display devices such as monitors of notebook computers and desktop computers, viewfinders of video cameras, projection displays, etc., and have recently been able to use them in televisions. It is also used as an optoelectronics related element, such as an optical printer head, an optical Fourier conversion element, a light bulb. As a conventional liquid crystal display element, a display element using a nematic liquid crystal is a mainstream, in which the alignment direction of the liquid crystal in the vicinity of one substrate and the alignment direction of the liquid crystal in the vicinity of the other substrate are twisted at an angle of 90 degrees. BACKGROUND ART Liquid crystal display devices in a nematic (TN) mode, a super twisted nematic (STN) mode in which the orientation direction is usually twisted at an angle of 180 degrees or more, and a so-called thin-film-transistor (TFT) mode using a thin film transistor have been put to practical use.

However, such a liquid crystal display element has a narrow viewing angle in which an image can be visually recognized appropriately, the luminance and contrast may be lowered when viewed in the oblique direction, and the luminance may be reversed in the middle tones. In recent years, such a problem of viewing angle is TN type liquid crystal display element using an optical compensation film, MVA (Multi-domain Vertical Alignment) mode which used the vertical alignment and protrusion structure technology together (for example, refer patent document 1), or It is being improved by the IPS (In-Plane Switching) mode of a transverse electric field system (for example, refer patent document 2).

The development of the liquid crystal display element technology is achieved not only by the improvement of such a drive system and an element structure, but also by the improvement of the structural member used for a liquid crystal display element. Among the constituent members used for the display elements, in particular, the liquid crystal alignment film is one of important factors related to the display quality of the liquid crystal display element, and the role of the liquid crystal alignment layer is becoming increasingly important as the quality of the display element is improved.

In such a liquid crystal alignment film, it is necessary to uniformly control the molecular arrangement of the liquid crystal for uniform display characteristics of the liquid crystal display element. For this purpose, the liquid crystal molecules on the substrate are uniformly bent in one direction, and a constant inclination angle from the surface of the substrate is also provided. It is required to express (pretilt angle). Thus, the liquid crystal aligning film which arranges the direction of the liquid crystal molecule on a board | substrate similarly is an important and indispensable technique in the manufacturing process of a liquid crystal display element.

A liquid crystal aligning film is manufactured from a liquid crystal aligning agent. The liquid crystal aligning agent currently used mainly is the solution which melt | dissolved polyamic acid or soluble polyimide in the organic solvent. After apply | coating such a solution to a board | substrate, it forms into a film by means, such as a heating, and forms a polyimide-type liquid crystal aligning film. Various liquid crystal aligning agents other than polyamic acid are also examined, but they are hardly put into practical use in view of heat resistance, chemical resistance (liquid crystal resistance), coating property, liquid crystal alignment property, electrical properties, optical properties, display properties, and the like.

Industrially, the rubbing method which can carry out high speed processing of large area easily is widely used as an orientation treatment method. The rubbing method is a treatment which rubs the surface of a liquid crystal aligning film to one direction using the cloth | flock which flocked fibers, such as nylon, rayon, and polyester, and can obtain the same orientation of a liquid crystal molecule by this. However, problems such as dust generation and static electricity generation by the rubbing method have been pointed out.

So far, the following two are proposed as an orientation mechanism of the liquid crystal on the liquid crystal aligning film which performed the orientation process by the rubbing process.

(1) the surface shape effect of the liquid crystal aligning film resulting from the micro groove generated by a rubbing process, and

(2) Intermolecular interaction with the liquid crystal aligning film uniaxially oriented by a rubbing process, and the liquid crystal monomolecule layer which contacts this liquid crystal aligning film.

In recent years, it has been confirmed that the contribution of the surface shape effect of (1) is relatively small, and the contribution of the intermolecular interaction of (2) is dominant.

On the other hand, regarding the photo-alignment method which irradiates light and performs an orientation process, many orientation mechanisms, such as a photolysis method, a photoisomerization method, a photodimerization method, and a photocrosslinking method, are proposed (for example, Nonpatent literature 1, See Patent Document 3 and Patent Document 4). In particular, since the photo-alignment method is a non-contact alignment method unlike the rubbing method, it is considered that only the intermolecular interaction of (2) acts as the alignment mechanism of the liquid crystal. In addition, since the photo-alignment treatment method is a non-contact system, in principle, dust generation and static electricity generation are less than that of the rubbing treatment method.

Therefore, in particular, by performing the alignment treatment by the photo-alignment method and using the liquid crystal alignment film having good alignment property, it is possible to control the molecular alignment state of the liquid crystal monomolecular layer in contact with the liquid crystal alignment film to improve the performance as a liquid crystal display element.

[Prior Art Literature]

[Patent Document]

Patent Document 1: Japanese Patent No. 2947350

Patent Document 2: Japanese Patent No. 2940354

Patent Document 3: Japanese Patent Application Laid-Open No. 2005-275364

Patent Document 4: Japanese Patent Application Laid-Open No. 11-15001

[Non-Patent Documents]

[Non-Patent Document 1] Liquid Crystal, Vol. 3, No. 4, page 262, 1999.

An object of the present invention is to provide an alignment film having particularly good orientation, little coloring, and high light resistance.

As a result of research and development, the present inventors have found that by blending a polymer having liquid crystallinity in a photoalignment agent, the photoalignment can be improved, the stability of the alignment is high, and the coloring when the film is formed can be reduced. It was found that the present invention was completed. The photoalignment agent of this invention can be shown in following [1].

[1] A photoalignment agent containing at least one of the polymers having the photo-alignment ability as the A component, and containing at least one of the polymers having the liquid crystal temperature range in the range of 100 to 300 ° C as the B component.

When the photoalignment agent of this invention is used, for example as a liquid crystal aligning agent, the film | membrane which has liquid crystal aligning property equivalent to or more than the orientation by a rubbing method can be obtained by light irradiation for a short time. In addition, the coloring of the film can be significantly reduced. Moreover, when irradiating light, such as a backlight, the photoalignment film which does not have the orientation change by the light can be obtained.

The term used by this invention is demonstrated. The compound represented by formula (I-1) may be described as compound (I-1). The same may be abbreviated also about the compound represented by another formula. The term "arbitrary" used when defining a chemical structural formula is arbitrary for the number as well as the position. In the chemical structural formula, a group enclosing a letter (for example B) in a hexagon means a group of a ring structure (ring B), and the group Me means methyl.

The present invention comprises the above-mentioned [1] and the following [2] to [12].

[2] The photoalignment agent according to [1], wherein the component A is at least one polymer selected from the group consisting of polyamic acid, partially imidized polyamic acid and polyimide.

[3] The photo-alignment agent according to [1], wherein the component A is at least one polymer selected from the group consisting of polyamic acid, partially imidized polyamic acid and polyimide, and is a polymer having a photosensitive group in the main chain.

[4] At least one polymer selected from the group consisting of polyamic acid, partially imidized polyamic acid, and polyimide, wherein component A is selected from formulas (I) to (V) and (X) in the main chain; At least one liquid crystalline polymer selected from the group consisting of a polymer having at least one, and the B component is a polyamic acid, a partially imidized polyamic acid and a polyimide, wherein two -CH _2- A polymer having a linear alkylene structure of 6 to 20 carbon atoms, which may be substituted with O-, -NH-, -N (CH ₃ )-, or -Si (CH ₃ ) ₂ OSi (CH ₃ ) _2- Photo-alignment agent as described in [1]:

Wherein R ¹ , R ² and R ³ are independently divalent groups.

[5] The component A is formula (I-1) to formula (I-3), formula (II-1) to formula (II-3), formula (III-1), formula (IV-1) to formula ( The photoalignment agent as described in [4] which is a polymer obtained using IV-3), at least one of the compound represented by Formula (V-1) and Formula (X-1)-Formula (X-8) as a raw material. :

[6] The photoalignment agent according to [4], wherein the component B is a polyimide having a structural unit represented by the formula (VI) or a polyamic acid thereof.

Wherein R ⁴ is one or two non-adjacent -CH ₂ -to -O-, -NH-, -N (CH ₃ )-, or -Si (CH ₃ ) ₂ OSi (CH ₃ ) _2- It may be a C2-C20 alkylene which may be substituted, the divalent group represented by Formula (VIII), or the divalent group represented by Formula (IX), and may differ for every structural unit; More than 60% of the total number of units is one in which R ⁴ is or two non-adjacent two -CH ₂ -is -O-, -NH-, -N (CH ₃ )-, or -Si (CH ₃ ) ₂ OSi (CH _{3) 2} - Im may be substituted carbon atoms, alkylene of 6 to 20 in a structural unit with:

In formula (VIII), X ¹ and X ² are a single bond, —O—, —COO—, —OCO—, —NH—, —CONH—, or alkylene having 1 to 12 carbon atoms; G ¹ and G ² are divalent groups containing 1 to 3 rings selected from a single bond or an aromatic ring having 6 to 12 carbon atoms and an alicyclic ring having 3 to 12 carbon atoms; R ⁵ is hydrogen, fluorine, —CN, —OH, or alkyl having 1 to 30 carbon atoms, perfluoroalkyl or alkoxy; When X ¹ , G ¹ , X ² and G ² are all single bonds, R ⁵ is alkyl, perfluoroalkyl or alkoxy having 3 to 30 carbon atoms, G ² is a single bond and X ² is not a single bond; If not alkylene, R ⁵ is hydrogen or alkyl of 3 to 30 carbon atoms, and when G ¹ and G ² are both single bonds, the sum of the carbon numbers of X ¹ , X ² and R ⁵ is 3 or more:

In formula (IX), R ⁶ is hydrogen or alkyl having 1 to 12 carbon atoms; Ring B is 1,4-phenylene in which arbitrary hydrogen may be substituted by alkyl having 1 to 4 carbon atoms, or 1,4-cyclohexylene in which arbitrary hydrogen may be substituted by alkyl having 1 to 4 carbon atoms ego; X ⁰ is a single bond or alkylene having 1 to 5 carbon atoms; s is an integer of 0 to 3; When s is 2, two rings B may be the same or different, and two X ⁰ may be the same or different, and when s is 3, three or any two rings B may be the same or different. And three or any two X ⁰ may be the same or different; Z ¹ and Z ² are independently a single bond, —CH ₂ —, —CH ₂ CH ₂ — or —O—; t1 and t2 are independently integers of 0 to 3; when t1 is 2, two Z ¹ may be the same or different; when t1 is 3, three or any two Z ¹ may be the same or different; when t2 is 2, the two Z ² may be the same or different; When t2 is 3, three or any two Z ² may be the same or different.

[7] A component is represented by formulas (I-1) to (I-3), formulas (II-1) to (II-3), formulas (III-1), and formulas (IV-1) to ( IV-3), a polymer obtained by using at least one of the compounds represented by formulas (V-1) and (X-1) to (X-8) as raw materials, and the B component is represented by formula (VI). The photoalignment agent as described in [4] which is a polyimide which is a polyimide which has a structural unit represented or its precursor:

Wherein R ⁴ is one or two non-adjacent -CH ₂ -to -O-, -NH-, -N (CH ₃ )-, or -Si (CH ₃ ) ₂ OSi (CH ₃ ) _2- It may be a C2-C20 alkylene which may be substituted, the divalent group represented by Formula (VIII), or the divalent group represented by Formula (IX), and may differ for every structural unit; More than 60% of the total number of units is one in which R ⁴ is or two non-adjacent two -CH ₂ -is -O-, -NH-, -N (CH ₃ )-, or -Si (CH ₃ ) ₂ OSi (CH _{3) 2} - Im may be substituted carbon atoms, alkylene of 6 to 20 in a structural unit with:

In formula (VIII), X ¹ and X ² are a single bond, —O—, —COO—, —OCO—, —NH—, —CONH—, or alkylene having 1 to 12 carbon atoms; G ¹ and G ² are divalent groups containing 1 to 3 rings selected from a single bond or an aromatic ring having 6 to 12 carbon atoms and an alicyclic ring having 3 to 12 carbon atoms; R ⁵ is hydrogen, fluorine, —CN, —OH, or alkyl having 1 to 30 carbon atoms, perfluoroalkyl or alkoxy; When X ¹ , G ¹ , X ² and G ² are all single bonds, R ⁵ is alkyl, perfluoroalkyl or alkoxy having 3 to 30 carbon atoms, G ² is a single bond and X ² is not a single bond; If not alkylene, R ⁵ is hydrogen or alkyl of 3 to 30 carbon atoms, and when G ¹ and G ² are both single bonds, the sum of the carbon numbers of X ¹ , X ² and R ⁵ is 3 or more:

In formula (IX), R ⁶ is hydrogen or alkyl having 1 to 12 carbon atoms; Ring B is 1,4-phenylene in which arbitrary hydrogen may be substituted by alkyl having 1 to 4 carbon atoms, or 1,4-cyclohexylene in which arbitrary hydrogen may be substituted by alkyl having 1 to 4 carbon atoms ego; X ⁰ is a single bond or alkylene having 1 to 5 carbon atoms; s is an integer of 0 to 3; When s is 2, two rings B may be the same or different, and two X ⁰ may be the same or different, and when s is 3, three or any two rings B may be the same or different. And three or any two X ⁰ may be the same or different; Z ¹ and Z ² are independently a single bond, —CH ₂ —, —CH ₂ CH ₂ — or —O—; t1 and t2 are independently integers of 0 to 3; when t1 is 2, two Z ¹ may be the same or different; when t1 is 3, three or any two Z ¹ may be the same or different; when t2 is 2, the two Z ² may be the same or different; When t2 is 3, three or any two Z ² may be the same or different.

[8] R ⁴ in formula (VI) is an alkylene having 2 to 20 carbon atoms or a divalent group represented by formula (VIII-1), and may be different for each structural unit; The photoalignment agent as described in [7] whose 60% or more of total number of structural units is a structural unit whose R <^4> is C6-C20 alkylene:

Wherein ring B ¹ and ring B ² are independently a single bond or 1,4-cyclohexylene, G ³ is a single bond or —CH ₂ CH ₂ —, and R ⁷ is hydrogen or alkyl of 1 to 20 carbon atoms .

[9] The photoalignment agent according to any one of [1] to [8], wherein the proportion of the A component based on the total weight of the A component and the B component is 10 to 90% by weight.

[10] A liquid crystal alignment film produced using the photoalignment agent according to any one of [1] to [9].

[11] A liquid crystal display device manufactured using the photoalignment film according to [10].

[12] A film is formed by coating a substrate with a photoaligning agent containing a polymer having a photo-alignment ability as a component A, and containing a polymer having a liquid crystal temperature range as a component B in a range of 100 to 300 ° C. After aligning the film, a heat treatment for raising the temperature to the liquid crystal temperature of the B component is performed.

The A component of the photoalignment agent of the present invention is important not only for inducing and generating anisotropy by light in the film when the photoalignment agent of the present invention is produced as a film, but also for maintaining the anisotropy. For example, when employing a method of forming an oriented film described later, in which a polyamic acid is used as the A component and irradiation is performed after irradiation with light to improve the optical orientation, the firing is usually performed so as not to cause a decrease in anisotropy due to heating. It is preferable to select a component which is non-liquid crystalline at a temperature range of 100 to 300 ° C. For the same reason as this, it is further preferable to select a component having no glass transition point (Tg) in the temperature range of 300 ° C or lower. Specifically, as the A component, a polyamic acid having a photo-alignment ability, a polymer partially imidized with the polyamic acid, or a polyimide obtained by completely dehydrating this polyamic acid is preferable, and those having a photosensitive group in the main chain thereof are preferred. More preferred are polymers.

There is no restriction | limiting in particular in the photosensitive member which a polymer which has a photo-alignment ability, ie, a photo-alignable polymer, can select all well-known photosensitive groups. Examples of known photosensitive groups include azobenzene derivatives, maleimide derivatives, chalcone derivatives, cinnamic acid derivatives, 1,2-vinylene derivatives, 1,2-acetylene derivatives, spiropyrane derivatives, spirobenzopyran derivatives and loose groups It is a photosensitive group included in a fulgide derivative.

The photo-alignment agent of this invention is a non-liquid crystalline polyamic acid which has at least one of the photosensitive groups represented by Formula (I)-Formula (V) and Formula (X) in a principal chain, and the polymer which partially imidated this polyamic acid. And at least one of at least one polymer selected from the group consisting of polyimides obtained by completely dehydrating this polyamic acid.

R <^1> , R <^2> and R <^3> in formula (I)-(V) are aromatic divalent groups independently. Preferable examples of the aromatic divalent group include 1,4-phenylene, 1,3-phenylene, 2-methyl-1,4-phenylene, 2-methyl-1,3-phenylene, 4,4'- Biphenylene and diphenylmethane-4,4'-diyl, and any hydrogen of these rings may be substituted with fluorine or chlorine. Among these groups, 1,4-phenylene and 1,3-phenylene are more preferable, and 1,4-phenylene is most preferable.

By selecting the photosensitive groups represented by formulas (I) to (V) and formula (X), the properties of the photoalignment agent of the present invention that the light alignment property is large and the coloration is small can be expressed to the maximum. Two isomers of cis or trans exist in the double bond of the photosensitive group of formula (III) and formula (V), and the photo-alignment agent of the present invention may use any of these isomers.

What is necessary is just to use diamine and / or carboxylic dianhydride which has such a photosensitive group as a raw material in order to obtain the polyamic acid which has one or more of the photosensitive groups represented by Formula (I)-Formula (V) and Formula (X) in a principal chain. In order to obtain especially high photo-alignment property, it is preferable to use the raw material which has a photosensitive group in diamine.

The diamine of Formula (I-1)-Formula (V-1) is mentioned as a especially preferable example among the diamine which has a photosensitive group represented by Formula (I)-Formula (V).

The preferable example of the diamine or tetracarboxylic dianhydride which has a photosensitive group represented by Formula (X) is shown next.

According to the characteristic requested | required of an oriented film, when manufacturing the polymer as A component of this invention, the diamine which has the said photosensitive group, and the well-known diamine which does not have a photosensitive group can be used together. For example, when an alignment film is used as an alignment film for nematic liquid crystal compositions in liquid crystal display applications, so-called electrical characteristics, which exhibit high voltage retention (VHR) and are difficult to cause burn-in, Excellent known diamines can be used.

As a preferable thing of such a well-known diamine, the diamine represented by Formula (2) is mentioned.

In formula (2), A ¹ , A ² , A ³ and A ⁴ are independently cyclohexylene or phenylene; X ³ and X ⁴ are independently a single bond, alkylene having 1 to 5 carbon atoms, or —O—; X ⁵ and X ⁶ are independently a single bond, —CH ₂ —, —CH ₂ CH ₂ —, —O—, or —S—; Y ¹ is -CH _2- , -C (R ¹¹ ) (R ¹² )-, -CO- or -SO _2- , and R ¹¹ and R ¹² are independently hydrogen, alkyl having 1 to 12 carbons, or 1 carbon 12 to perfluoroalkyl; m1, m2, m3, m4 and n are independently 0 or 1. In the cyclohexylene and phenylene, any hydrogen may be substituted with alkyl or benzyl having 1 to 4 carbon atoms, and the bonding position of such a substituent is arbitrary. Although the position of the free group of cyclohexylene and phenylene is also arbitrary, 1, 3- or 1, 4- is preferable and 1, 4- is the most preferable.

The preferable example of the diamine represented by Formula (2) is shown next.

Among them, from the viewpoint of imparting high VHR to the liquid crystal alignment film to suppress the burn-in phenomenon, the formulas (2-6) to (2-23), (2-38), (2-39), and formula Diamine represented by (2-44), formula (2-45), formula (2-49), or formula (2-50) to formula (2-54) is more preferable, and formula (2-6), In formula (2-7), formula (2-11), formula (2-12) to formula (2-16), formula (2-19) to formula (2-24), or formula (2-51) Diamine represented is more preferable.

The use ratio of the diamine which does not have the said photosensitive group in this invention can be arbitrarily selected according to the orientation and electrical characteristics made into the objective. However, when the use ratio of such diamine is large, since orientation property falls, it is preferable that this use ratio is 0-50 mol% with respect to the whole quantity of the diamine used when synthesize | combining the polyimide or polyamic acid as A component, and 0 It is more preferable that it is-30 mol%.

Another example of the diamine having no photosensitive group that can be suitably used for producing the polymer of the component A is a diamine having a side chain group represented by the formula (3) or (4).

In formula (3), X ¹ and X ² are independently a single bond, -O-, -COO-, -OCO-, -NH-, -CONH- or alkylene having 1 to 12 carbon atoms; G ¹ and G ² are independently a divalent group comprising 1 to 3 rings selected from a single bond or an aromatic ring having 6 to 12 carbon atoms and an alicyclic ring having 3 to 12 carbon atoms; R ⁵ is hydrogen, fluorine, —CN, —OH, or alkyl having 1 to 30 carbon atoms, perfluoroalkyl or alkoxy. Provided that when X ¹ , G ¹ , X ² and G ² are all single bonds, R ⁵ is alkyl having 3 to 30 carbons, perfluoroalkyl or alkoxy; When G ² is a single bond and X ² is neither a single bond nor an alkylene, then R ⁵ is hydrogen or alkyl; In addition, when G <^1> and G <^2> are all single bonds, the sum total of carbon number of X <^1> , X <^2> and R <^2> is three or more.

In the above formula (3), the two amino groups are bonded to the carbon of the benzene ring, but it is preferable that the bond position relationship between the two amino groups is meta or para. The two amino groups are preferably bonded at positions 3 and 5, or at positions 2 and 5, and particularly preferably at positions 3 and 5 when the bond position of X ¹ is set to position ¹ , respectively. Do.

In formula (4), R ⁵ is hydrogen or alkyl having 1 to 12 carbon atoms; Ring B is 1,4-phenylene in which arbitrary hydrogen may be substituted by alkyl having 1 to 4 carbon atoms, or 1,4-cyclohexylene in which arbitrary hydrogen may be substituted by alkyl having 1 to 4 carbon atoms ego; X ⁰ is a single bond or alkylene having 1 to 5 carbon atoms; s is an integer of 0 to 3; when s is 2 the two rings B may be the same or different and two X ⁰ may be the same or different; when s is 3 three or any two rings B may be the same or different and three or any two X ⁰ may be the same or different; Z ¹ and Z ² are independently a single bond, —CH ₂ —, —CH ₂ CH ₂ — or —O—; t1 and t2 are independently integers of 0 to 3; when t1 is 2, two Z ¹ may be the same or different; when t1 is 3, three or any two Z ¹ may be the same or different; when t2 is 2, the two Z ² may be the same or different; When t2 is 3, three or any two Z ² may be the same or different.

The preferable example of the diamine represented by Formula (3) is shown next.

In formula (3-1)-(3-25), R <^20> is C1-C20 alkyl or alkoxy, Preferably it is C5-C16 alkyl. R <^21> is C1-C20 alkyl or alkoxy, Preferably it is C3-C10 alkyl. R ²² is alkyl having 4 to 20 carbons, preferably alkyl having 6 to 16 carbons. R ²³ is alkyl having 6 to 20 carbon atoms, preferably alkyl having 8 to 20 carbon atoms. R <^24> is C3-C20 alkyl or alkoxy, Preferably it is C5-C12 alkyl. R <^25> is C1-C20 alkyl or alkoxy, Preferably it is C3-C10 alkyl.

Among these diamines, a more preferable example is the diamine represented by Formula (3-1), Formula (3-2), Formula (3-4), Formula (3-5), and Formula (3-6), respectively. Further preferred examples are diamines represented by formulas (3-1) and (3-2), respectively.

The preferable example of the diamine represented by Formula (4) is shown next.

In formulas (4-1) to (4-16), R ²⁶ is hydrogen or alkyl having 1 to 12 carbon atoms or alkoxy, and preferably alkyl having 4 to 7 carbon atoms.

The use ratio of the diamine which has the said side chain group in this invention can be arbitrarily selected according to the orientation, electrical property, or pretilt angle made into the objective. In order to express a pretilt angle of 2 degrees or more in particular, it is preferable to make this use ratio into 5 to 70 mol% in the diamine whole quantity used when manufacturing the polymer of A component, and to make it 10 to 50 mol% more. desirable.

When manufacturing the polymer of A component, one or more of siloxane diamine can also be used together, The diamine represented by Formula (15) is mentioned as a preferable example of this siloxane diamine.

In formula (15), R ³⁰ and R ³¹ are each independently alkyl or phenyl having 1 to 3 carbon atoms, R ³² is alkylene, phenylene or alkyl substituted phenylene having 1 to 6 carbon atoms, and y is 1 It is an integer of -10.

As a specific example of the diamine represented by Formula (15), the following compound or polymer is mentioned.

The molecular weight of the polymer of Formula (15-2) is 850-3000.

When using such a siloxane-based diamine, the addition amount is 0.5-30 mol with respect to the whole quantity of the diamine used as a raw material when manufacturing A component and B component in order to express the said effect and to prevent the deterioration of other characteristics. % Is suitable and 1-10 mol% is more suitable.

In such a diamine, the aromatic system (including a heteroaromatic ring system) in which the amino group was couple | bonded with the aromatic ring directly is especially preferable from a viewpoint of providing favorable orientation to a liquid crystal. Moreover, it is preferable that it is a structure which does not contain oxygen and sulfur, such as ester and ether bond which are a cause of the fall of the electrical property of a liquid crystal display element. However, even if it has such a structure, it will not be a problem at all if it is an amount which does not adversely affect an electrical characteristic.

Tetracarboxylic dianhydride, which is a raw material for producing a polymer of A component, can be selected from known compounds without limitation. Such tetracarboxylic dianhydride is an aromatic dicarboxylic acid anhydride and heterocyclic aromatic ring dicarboxylic anhydride in which two 2-oxapropane-1,3-diyl groups (dicarboxylic acid anhydride groups) are bonded directly to an aromatic ring, together with aromatic It may belong to any one group of aliphatic dicarboxylic anhydride and heterocyclic aliphatic dicarboxylic anhydride in which the dicarboxylic acid anhydride group is not directly bonded to the ring. It is preferable that a polyimide or polyamic acid is a structure which does not contain oxygen and sulfur, such as ester and ether bond which are a cause of the fall of the electrical property of a liquid crystal display element. Therefore, it is preferable that tetracarboxylic dianhydride is also a structure which does not contain oxygen or sulfur. However, even if it has such a structure, it will not be a problem at all if it is the quantity which does not adversely affect an electrical characteristic.

Tetracarboxylic dianhydride is represented by Formula (20).

Preferred examples of R ⁴⁰ in formula (20) are tetravalent groups represented by formulas (21) to (29).

(G ³ is a single bond, alkylene having 1 to 12 carbon atoms, 1,4-phenylene, or 1,4-cyclohexylene, and X ⁷ is independently a single bond or -CH _2- )

(R ⁴¹ , R ⁴² , R ⁴³ and R ⁴⁴ are independently hydrogen, methyl, ethyl or phenyl)

(Ring D ¹ is a cyclohexane ring or a benzene ring)

(G ⁴ is a single bond, —CH ₂ —, —CH ₂ CH ₂ —, —O—, —CO—, —S—, —C (CH ₃ ) ₂ —, or —C (CF ₃ ) ₂ — , Ring D ² is independently a cyclohexane ring or a benzene ring)

(R ⁴⁵ is hydrogen or methyl)

(X ⁸ is, independently, a single bond or —CH ₂ — and v is 1 or 2)

(X ⁶ is a single bond or -CH _2- )

(R ⁴⁶ is hydrogen, methyl, ethyl or phenyl, ring D ³ is a cyclohexane ring or a benzene ring)

(w1 and w2 are independently 0 or 1).

As a specific example of the said tetracarboxylic dianhydride, the compound of the following formula (A-1)-a formula (A-43) is mentioned.

In such tetracarboxylic dianhydride, from a viewpoint of improving the photo-alignment performance of a liquid crystal aligning film, Formula (A-1), Formula (A-2), Formula (A-12), Formula (A-14), Formula ( A-18), formula (A-20), formula (A-21), formula (A-28), formula (A-30), formula (A-37), or a compound of formula (A-40) It is preferable to use, and it is especially preferable to use the compound of Formula (A-1), Formula (A-12), Formula (A-14), or Formula (A-18). Moreover, from a viewpoint of improving VHR of a liquid crystal aligning film, or reducing coloring, Formula (A-14), Formula (A-18), Formula (A-19), Formula (A-20), Formula (A-21) ), Formula (A-28), formula (A-29), formula (A-30), formula (A-32), formula (A-39), formula (A-40), formula (A-41) Or it is preferable to use the compound of formula (A-43), and it is especially preferable to use the compound of formula (A-14), a formula (A-18), or a formula (A-21). Tetracarboxylic dianhydride is not limited to these, Another well-known compound can also be used within the range which can achieve the objective of this invention. In addition, these tetracarboxylic dianhydride can also be used individually or in combination of 2 or more types.

As another structural material used for the photo-alignment agent of this invention, selection of the polymer which shows liquid crystallinity, or B component which is its precursor is important. The component B in the present invention is used for the purpose of amplifying the photoinduced anisotropy of the alignment film of the present invention. At this time, in order to obtain larger orientation, it is preferable to use a liquid crystalline polymer having a liquid crystal phase at a lower temperature. However, in order to improve the stability of orientation, it is preferable to use the liquid crystalline polymer which has a liquid crystal phase at comparatively high temperature. From this viewpoint, the B component which has liquid crystal temperature in 100-300 degreeC, Preferably it is 150-300 degreeC is used. When manufacturing the alignment film of this invention, in order to make the orientation amplification by B component act | work, it is essential to use together the heat processing to the liquid crystal temperature range. Moreover, when forming an oriented film by the method of performing imidation after photoalignment using polyamic acid for A component as mentioned later, it is preferable to imidize A component in the liquid crystal temperature range of B component.

The kind of polymer of the B component in this invention is not specifically limited, Any known liquid crystalline polymer can be used. However, the most suitable liquid crystalline polymer from the viewpoint of the stability of the orientation includes a polyamic acid which becomes a polyimide when formed into a film, a polyamic acid ester in which the carboxyl group of the polyamic acid is esterified, or a soluble polyimide. Of course, from a practical point of view, partially imidized polyamic acid may also be used. As a specific example of this liquid crystalline polyimide, Macromol. Chem. The polyimide which has a structural unit represented by Formula (VI) described in Phys., 198, 519 (1997) etc. is mentioned.

R ⁴ is an alkylene having 2 to 20 carbon atoms, a divalent group represented by formula (VIII), or a divalent group represented by formula (IX), and may be different for each structural unit; 60% or more of the total number of structural units is a structural unit in which R <^4> is C6-C20 alkylene. When R ⁴ is alkylene, one or two non-adjacent -CH ₂ -of these alkylenes are -O-, -NH-, -N (CH ₃ )-, or -Si (CH ₃ ) ₂ OSi (CH ₃ ) ₂ -may be substituted.

In order to express liquid crystallinity of the component B, for example, a structural unit in which R ⁴ in formula (VI) is alkylene having 6 to 20 carbon atoms, that is, a structural unit having a flexible spacer is hexavalent to the entire structural unit. It is important to stay longer. However, even if the presence of such a structural unit is 60% or less of polymer, if it can express liquid crystallinity, it can select as B component.

In order to express the liquid crystalline property of B component, it is preferable to use acid anhydride or diamine which has the skeleton which the aromatic ring connected to, for example, elongate plane (core) extended as a raw material, for example. It is preferable to select the ratio of the raw material having such a core in the range of 50 to 100% by weight, and more preferably in the range of 70 to 100% by weight based on the total amount of the raw material. However, even if the proportion of the raw material having such a core is 50% by weight or less, the polymer can be selected as the B component if it is possible to express liquid crystallinity in the polymer obtained.

As long as the liquid crystallinity of B component is not impaired, another well-known acid anhydride or diamine can be used as a raw material of B component. At this time, it is preferable to select the diamine represented by the following formula (VIII) or formula (IX) as a component of R <^4> as another well-known raw material especially at the point which maintains liquid crystallinity.

Wherein X ¹ and X ² are independently a single bond, —O—, —COO—, —OCO—, —NH—, —CONH—, or alkylene having 1 to 12 carbon atoms; G ¹ and G ² are independently a divalent group comprising a single bond or 1 to 3 rings selected from an aromatic ring having 6 to 12 carbon atoms and an alicyclic ring having 3 to 12 carbon atoms; R ⁵ is hydrogen, fluoro, —CH, —OH, or alkyl having 1 to 30 carbon atoms, perfluoroalkyl or alkoxy; When X ¹ , G ¹ , X ² and G ² are all single bonds, R ⁵ is alkyl, perfluoroalkyl or alkoxy having 3 to 30 carbon atoms, G ² is a single bond and X ² is not a single bond; When it is not alkylene, R <^5> is hydrogen or C3-C30 alkyl, and when G <^1> and G <^2> are single bonds, the sum total of carbon number of X <^1> , X <^2> and R <^5> is three or more.

Wherein R ⁵ is hydrogen or alkyl of 1 to 12 carbon atoms; Ring B is 1,4-phenylene in which arbitrary hydrogen may be substituted by alkyl having 1 to 4 carbon atoms, or 1,4-cyclohexylene in which arbitrary hydrogen may be substituted by alkyl having 1 to 4 carbon atoms ego; X ⁰ is a single bond or alkylene having 1 to 5 carbon atoms; s is an integer of 0 to 3; when s is 2, two rings B may be the same or different, and two X ⁰ may be the same or different; when s is 3, three or any two rings B may be the same or different, and three or any two X ⁰ may be the same or different; Z ¹ and Z ² are independently a single bond, —CH ₂ —, —CH ₂ CH ₂ — or —O—; t1 and t2 are independently integers of 0 to 3; when t1 is 2, two Z ¹ may be the same or different; when t1 is 3, three or any two Z ¹ may be the same or different; when t2 is 2, the two Z ² may be the same or different; When t2 is 3, three or any two Z ² may be the same or different.

When selecting the structural unit which has a structure of Formula (VIII) or Formula (IX), it is preferable that the abundance ratio of these structural units is 50% or less with respect to the whole structural unit in order to provide sufficient liquid crystallinity to B component. .

When the liquid crystal aligning film of this invention is used for IPS uses, selecting the structural unit only of C2-C20 alkylene as said R <^4> reduces the Pt angle of a liquid crystal, and improves the orientation with respect to an azimuth direction desirable. On the other hand, when used for TN or VA purposes, in order to control the Pt angle of a liquid crystal, it is preferable to include the structural unit which has a structure of said Formula (VIII) or Formula (IX) as R <^4> . At this time, in order to maintain the liquid crystallinity of the B component, it is more preferable to select the structure of Formula (VIII-1) as R ⁴ .

Wherein ring B ¹ and ring B ² are independently a single bond or 1,4-cyclohexylene, G ³ is a single bond or —CH ₂ CH ₂ —, and R ⁷ is hydrogen or alkyl of 1 to 20 carbon atoms .

The mixing ratio of the A component and the B component of the present invention may be arbitrarily selected in the range of 5 to 95% by weight, in accordance with the requirements for the photoalignment of the film, the stability of the orientation, and the coloring of the film. It is selectable and it is suitable to select in the range of 10-90 weight%. In order to improve photo-alignment at this time and to reduce coloring of a film, it is suitable to select this ratio in the range of 50 to 90 weight%. Moreover, in order to improve the stability of orientation, it is suitable to select this ratio in 30 to 80weight% of a range.

The alignment agent of the present invention may further contain an organosilicon compound from the viewpoint of adjusting the adhesion of the alignment film to the glass substrate. Examples of the organosilicon compound include aminopropyltrimethoxysilane, aminopropyltriethoxysilane, vinyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2- Aminoethyl) -3-aminopropyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxy Silane coupling agents such as silane and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane and silicone oils such as dimethylpolysiloxane, polydimethylsiloxane, and polydiphenylsiloxane.

The addition ratio with respect to the aligning agent of this organosilicon compound will not be restrict | limited especially if it is a range from which the effect of this invention is acquired. However, when the said organosilicon compound is added a lot, the orientation defect of a liquid crystal may arise when made into an oriented film. Therefore, when adding an organosilicon compound, it is preferable that the density | concentration is 0.01 to 5 weight% with respect to the weight of the polymer contained in an aligning agent, Especially preferably, it is the range of 0.1 to 3 weight%.

The alignment agent of the present invention may further contain a compound having two or more functional groups reacting with the carboxylic acid residues of the polyamic acid or its derivatives, and a so-called crosslinking agent, from the viewpoint of preventing the deterioration over time and deterioration of the environment. As an example of such a crosslinking agent, the polyfunctional epoxy, isocyanate material, etc. which are described in Unexamined-Japanese-Patent No. 3049699, Unexamined-Japanese-Patent No. 2005-275360, Unexamined-Japanese-Patent No. 10-212484, etc. are mentioned.

Moreover, the crosslinking agent itself reacts, and becomes a polymer of a mesh structure, and the crosslinking agent which improves the film strength of a polyamic acid or a polyimide can also be used for the same purpose. As such a crosslinking agent, the polyfunctional vinyl ether, maleimide, or bisaryl naziimide derivative as described in Unexamined-Japanese-Patent No. 10-310608, Unexamined-Japanese-Patent No. 2004-341030, etc. are mentioned. When using such a crosslinking agent, the preferable ratio is 5-100 weight% with respect to the total amount of a polymer component, More preferably, it is 10-50 weight%.

The alignment agent of this invention contains the solvent which has the ability to melt | dissolve polyamic acid or its derivative (s). Such a solvent can be suitably selected according to the purpose of use, including the solvent normally used in manufacture or use of a polyamic acid or its derivative (s). When such a solvent is illustrated, it is as follows.

Examples of aprotic polar organic solvents that are good solvents for polyamic acids include N-methyl-2-pyrrolidone (NMP), dimethylimidazolidinone, N-methylcaprolactam, N-methylpropionamide, N, N-dimethylacetamide, dimethyl sulfoxide, N, N-dimethylformamide (DMF), N, N-diethylformamide, N, N-diethylacetamide (DMAc), and γ-butyrolactone (GBL) Lactone, such as a), is mentioned.

As a solvent other than the above-mentioned solvents, examples of other solvents for the purpose of improving the coating properties include alkyl lactate, 3-methyl-3-methoxybutanol, tetralin, isophorone, ethylene glycol monobutyl ether (BCS), and the like. Diethylene glycol monoalkyl ethers such as ethylene glycol monoalkyl ether and diethylene glycol monoethyl ether, propylene glycol monoalkyl ethers such as ethylene glycol monoalkyl and phenyl acetate, triethylene glycol monoalkyl ether and propylene glycol monobutyl ether, Ester compounds, such as dipropylene glycol monoalkyl ether, such as malonic acid dialkyl, such as diethyl malonate, and dipropylene glycol monomethyl ether, and these glycol monoethers, are mentioned. Among these, NMP, dimethyl imidazolidinone, GBL, BCS, diethylene glycol monoethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, etc. can be used especially suitably for the said solvent.

The alignment agent of the present invention may further contain various additives as desired. For example, when improving applicability | paintability, you may contain surfactant according to such an objective, and when antistatic agent needs to further improve antistatic agent in a suitable quantity.

Although the density | concentration of the polyamic acid or its derivative in the aligning agent of this invention is not specifically limited, It is preferable that it is 0.1-40 weight%. When apply | coating this aligning agent to a board | substrate, in order to adjust film thickness, the operation which dilutes the polyamic acid contained with the solvent in advance may be needed.

In order to express better properties as the alignment film, the alignment agent in the present invention may be mixed with at least one kind selected from all other known polymers. At this time, in order to express the effect of this invention, the sum total of A component and B component which occupy for all the polymers is 50 weight% or more, and 80 weight% or more is more preferable.

Solid content concentration in the aligning agent of this invention is not specifically limited, What is necessary is just to select the optimal value according to the following various application | coating methods. Usually, in order to suppress the unevenness, pinhole, etc. at the time of application | coating, it is 0.1-30 weight% with respect to a varnish weight, More preferably, it is 1-10 weight%.

As described above, the alignment film of the present invention can be obtained by using an alignment agent (varnish) containing the above-mentioned A component, B component, other components already added as required, and a solvent for dissolving them. have. This alignment agent is apply | coated to a board | substrate by the method demonstrated below, and a solvent is heat-removed (preliminary baking) at comparatively low temperature as needed. In addition, in order to further promote imidization or solvent removal of the polyimide, polyamic acid, or polyamic acid derivative, and to express the characteristics of the alignment film, it is heated (main firing) at a relatively high temperature. It can obtain by irradiating light to the film | membrane obtained in this way and orienting a polymer.

At this time, it is preferable that the orientation film of this invention is manufactured in the following procedures using polyamic acid as A component from a viewpoint of expressing sufficient orientation.

(1) The varnish is applied onto a substrate by a brush coating method, dipping method, spinner method, spray method, printing method, or the like.

(2) The film formed on the substrate is heated to 50 to 120 캜, preferably 80 to 100 캜 to evaporate the solvent.

(3) Light is irradiated to the film to orient the polyamic acid in the film.

(4) The film in which the polyamic acid is oriented is imidized by heating to 150 to 300 ° C, preferably 180 to 250 ° C.

On the other hand, when a predetermined pretilt angle is to be expressed in a liquid crystal display device using an alignment film, a method of irradiating linearly polarized light from an arbitrary angle with respect to a substrate when irradiating light, and linearly polarized light from a vertical direction with respect to the substrate Irradiation and unpolarized irradiation from any angle can be performed by a combination method.

In the manufacture of the alignment film of the present invention, linearly polarized light can be used for the alignment of the polyamic acid. The polyamic acid main chain is oriented in a direction perpendicular to the polarization direction of linearly polarized light by irradiation of linearly polarized light. The linearly polarized light is not particularly limited as long as it is light that can orient the polyamic acid in the film. The alignment film of the present invention can orientate the film by light irradiation of low energy. Therefore, it is preferable that the irradiation amount of linearly polarized light in the photo-alignment process of the said polyamic acid is 0.5-10J / cm <^2> . Moreover, it is preferable that the wavelength of linearly polarized light is 300-400 nm. Although the irradiation angle with respect to the film surface of linearly polarized light is not specifically limited, When it is going to express strong orientation control force with respect to a liquid crystal, it is preferable from a viewpoint of shortening an orientation processing time that it is as perpendicular | vertical as possible with respect to a film surface.

Moreover, in manufacture of the oriented film of this invention, the light irradiated to the said film in order to express a pretilt angle may be polarized light or unpolarized light. In the case where the pretilt angle is to be expressed, the irradiation amount of light irradiated to the film is preferably 0.5 to 10 J / cm ² , and the wavelength is preferably 300 to 400 nm. Although the irradiation angle with respect to the film surface of the light irradiated to the said film | membrane in order to express a pretilt angle is not specifically limited, It is preferable from a viewpoint of shortening an orientation processing time in 30-60 degree | times.

The alignment film of the present invention is characterized by particularly having anisotropy of large orientation. The magnitude of such anisotropy can be evaluated by the method using polarization IR as described in Unexamined-Japanese-Patent No. 2005-275364. Moreover, it can also evaluate by the method using ellipsometry, as shown in the following Example. When the orientation film of this invention is used as an orientation film for liquid crystal compositions, it is thought that the material which has larger anisotropy of a film has a large orientation control force with respect to a liquid crystal composition.

The alignment film of this invention can be used for orientation control of an optical compensation material and all other liquid crystal materials other than the orientation use of the liquid crystal composition for liquid crystal displays. In addition, since the alignment film of the present invention has great anisotropy, it can be used alone as an optical compensation material.

The present invention provides a pair of substrates disposed to face each other, an electrode formed on one or both sides of the facing surfaces of each of the pair of substrates, a liquid crystal alignment film formed on the facing surfaces of the pair of substrates, And a liquid crystal display device having a liquid crystal layer formed between the pair of substrates, wherein the liquid crystal alignment film is an alignment film of the present invention.

The electrode is not particularly limited as long as it is an electrode formed on one surface of the substrate. As such an electrode, ITO, a metal vapor deposition film, etc. are mentioned, for example. The electrode may be formed on the entire surface of one surface of the substrate, or may be formed in a desired shape that is patterned, for example. As said desired shape of an electrode, a comb-tooth type | mold or a zigzag structure etc. are mentioned, for example. An electrode may be formed in one board | substrate among a pair of board | substrates, and may be formed in both board | substrates. The form of electrode formation depends on the kind of liquid crystal display element, for example, in the case of an IPS type liquid crystal display element, an electrode is arrange | positioned at one side of the said pair of board | substrates, and in the case of other liquid crystal display elements, said pair The electrodes are arranged on both sides of the substrate. The liquid crystal alignment film is formed on the substrate or the electrode.

The said liquid crystal layer is formed in the form which a liquid crystal composition is clamped by the said pair of board | substrate which the surface in which the liquid crystal aligning film was formed faces. In formation of a liquid crystal layer, the spacer which forms a suitable space | interval through said pair of board | substrates, such as microparticles | fine-particles and a resin sheet, can be used as needed. It does not specifically limit to the said liquid crystal composition, A well-known liquid crystal composition can be used.

When the alignment film of this invention forms a liquid crystal display element as a liquid crystal aligning film, although the characteristic can be improved with respect to all the well-known liquid crystal compositions, the alignment film of this invention manufactured by the method mentioned above especially carries out a rubbing process. The effect is large in improving the orientation defect of a large screen display which is hard to implement. This large screen display is controlled to be driven by the TFT. Moreover, the liquid crystal composition used for such a TFT type liquid crystal display element is described in Unexamined-Japanese-Patent No. 3086228, Unexamined-Japanese-Patent No. 5-501735, and Unexamined-Japanese-Patent No. 9-255956. Therefore, it is preferable to use the alignment film of this invention in combination with the liquid crystal composition described in such a patent document.

As for the pretilt angle in the liquid crystal display element of this invention, the liquid crystal characteristic evaluation apparatus OMS-CA3 type which is a product made by Nakae Seiki Co., Ltd. is used, for example, Journal of Applied Physics, Vol. 48, No. 5, p. 1783-1792 (1977) can be measured by the crystal rotation (crystal rotation) method.

The liquid crystal display element of this invention is excellent in the electrical characteristics related to the reliability of a liquid crystal display element. As such electrical characteristics, voltage retention and ion density are mentioned.

The voltage retention VHR is a ratio at which the voltage applied to the liquid crystal display element is maintained in the liquid crystal display element between frame periods, and represents the display characteristics of the liquid crystal display element. The liquid crystal display device of the present invention uses a square wave of 5 V and a frequency of 30 Hz, has a voltage retention of 90.0% or more measured at a temperature of 60 ° C., and uses a square wave of 5 V and a frequency of 0.3 Hz. It is preferable from the viewpoint of preventing display defects that the voltage retention measured at the temperature of 占 폚 is 85.0% or more.

The ion density is a transient current other than that resulting from the driving of the liquid crystal generated when a voltage is applied to the liquid crystal display element, and represents the magnitude of the concentration of the ionic impurities contained in the liquid crystal in the liquid crystal display element.

It is preferable that the ion density of the liquid crystal display element of this invention is 500 pC or less from a viewpoint of preventing the burn-in of a liquid crystal display element.

[Example]

Hereinafter, although an Example and a comparative example demonstrate this invention, this invention is not limited to these Examples. Pyromellitic anhydride (PMDA, Compound (A-1)), 1,2,3,4-cyclobutanetetracarboxylic acid (CBTA, Compound (A-14)), Compound (2-13), and DATP are commercially available. The compound was purified by recrystallization and used in the experiment. 1,8-diaminooctane, 1,9-diaminononane, and 1,12-diaminododecane were distilled off the commercial item. Compound (I-1), Compound (II-1) and Compound (A-21) were respectively described in Tetrahedron, Vol. 60, 9977 (2004), Japanese Patent Laid-Open No. 5-65530, and Japanese Patent Laid-Open No. 58-109479. The following compound TPDA and compound (30) are described in Macromolecules, Vol. 28, 6368 (1995) and Japanese Patent Laid-Open No. 2004-341030. Compound (X-1) was used for the experiment by recrystallizing a commercial item with ethanol. Compound (3-5-1) was synthesize | combined by the method similar to the method of Unexamined-Japanese-Patent No. 2002-162630. The preparation of the polymer was carried out in a nitrogen stream.

The light irradiation irradiated the ultraviolet-ray of wavelength 310-380 nm vicinity using the 250W high pressure mercury lamp manufactured by Reiko. Irradiation was carried out at room temperature and in air.

The evaluation method of the liquid crystal display element used by the Example below is shown.

<Measurement of retardation, film thickness, and pretilt angle of alignment film>

It calculated | required using the spectroscopic ellipsometer M-2000U (made by J.A. Woollam Co. Inc.). For this example, the retardation value of the membrane increases in proportion to the degree of orientation of the polymer backbone. That is, what has a big retardation value has a big orientation degree.

<Measurement of UV-Vis Spectrum>

It measured on the basis of the glass substrate in which the oriented film is not formed using the UV-Vis spectrum measuring apparatus (Japan V-660).

<Voltage retention rate>

It carried out by the method as described in "Water, 14th liquid crystal discussion meeting notice p78 (1988)". The measurement was performed by applying a square wave of wave height ± 5 V to the cell. The measurement was performed at 60 ° C. This value is an index indicating how long the applied voltage is held after the frame period, and when this value is 100%, it indicates that all charges are held.

<Ion amount measurement (ion density) in liquid crystal>

According to the method of application physics, Vol. 65, No. 10, 1065 (1996), it measured using the Toyo Technica Co., Ltd. liquid crystal physical property measuring system 6254 type. It measured by the voltage range of +/- 10V and the temperature of 60 degreeC using the triangle wave of the frequency of 0.01 Hz. If the ion density is large, defects such as burn-in due to ionic impurities are likely to occur. In other words, the ion density is a physical property that is an index for predicting burn-in occurrence.

<Weight average molecular weight (Mw)>

The weight average molecular weight (Mw) of the polyamic acid in the liquid crystal aligning agent was gel permeation chromatography (GPC, manufactured by Shodex, GF7MHQ), and 0.6 wt% phosphoric acid-containing DMF was used as the eluent. Was measured as a standard solution.

<Phase transition point of polymer liquid crystal>

The thin film (film thickness about 70 nm) formed into the board | substrate was baked at 230 degreeC for 10 minutes, and observed by the polarizing microscope and calculated | required. The polymer liquid crystal obtained by separate reprecipitation was measured by a differential scanning calorimetry apparatus, but the measurement in the foregoing method was used because the thin film state and the phase transition temperature were different.

<Viscosity>

It measured at 25 degreeC using the viscometer (the Tokyo KK make, TV-22).

<Glass transition temperature>

It measured using the differential scanning calorimetry apparatus (DSC, the diamond DSC by the Perkin Elmer company).

Synthesis Example 1

<Production of Polyamic Acid Varnish A>

4,4'-Diaminotolan (Compound No. I-1; 1.2534 g, 6.018 mmol) was dissolved in N-methyl-2-pyrrolidone (NMP, 22.5 g), and pyromellitic anhydride (PMDA, 0.5901 g) , 3.009 mmol) and 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBTA, 0.6564 g, 3.009 mmol) were added while keeping the temperature below room temperature. After stirring for 2 hours, ethylene glycol monobutyl ether (BC, 22.5 g) was added. Its viscosity was 350 mPa · s. The solution was stirred at 60 ° C. for about 4 hours to obtain a varnish A having a viscosity of 33 mPa · s. The weight average molecular weight of the polyamic acid of this varnish was 45,000, and glass transition temperature (Tg) exceeded 300 degreeC.

Synthesis Examples 2 to 7

<Production of Polyamic Acid Varnishes B to G>

With the raw material composition shown in Table 1, varnish B-G of polyamic acid was manufactured by the method similar to the synthesis example 1, and the physical property was measured similarly to the synthesis example 1. In addition, the parenthesis shows mol%.

<Table 1>

[Synthesis Example 8]

<Production of Polyamic Acid Varnish I>

1,8-diaminooctane (DAO) (0.7009 g, 4.858 mmol) was dissolved in NMP (22.5 g), and TPDA (1.7991 g, 4.858 mmol) was added at room temperature. After stirring at 60 ° C. for 2 hours, it was cooled to room temperature and BC (22.5 g) was added to give varnish H. The viscosity of this varnish was 18.7 mPa · s. (Weight average molecular weight; 18,000). Moreover, the phase transition point (nematic-isotropic phase) was 235 degreeC.

Synthesis Example 9

<Production of Polyamic Acid Varnish J>

Varnish I was obtained in the same manner as in Synthesis example 6, using a mixture of DAO and 1,9-diaminononane (molar ratio 1: 1) instead of DAO. The viscosity of this varnish was 28.6 mPa · s. (Weight average molecular weight; 24,000). Moreover, the phase transition point (nematic-isotropic phase) was 212 degreeC.

Synthesis Example 10

<Production of Soluble Polyimide Varnish K>

DAO (0.7009 g, 4.858 mmol) was dissolved in NMP (22.5 g) and TPDA (1.7991 g, 4.858 mmol) was added at room temperature. After stirring at 60 ° C. for 2 hours, it was cooled to room temperature, acetic anhydride (0.58 g, 5.7 mmol) and pyridine (0.45 g, 5.7 mmol) were added, and the mixture was stirred at room temperature for 3 hours. This reaction solution was added to pure water (500 ml), and the resulting precipitate was filtered off. The precipitate obtained was washed twice with 100 ml of pure water and then vacuum dried at 100 캜 for 8 hours. This polymer (1.0 g) was dissolved in NMP (10 g), BC (10 g) was added to make varnish J. The viscosity of this varnish was 9.8 mPa * s. (Weight average molecular weight; 16,000). Moreover, the phase transition point (nematic-isotropic phase) was 231 degreeC.

Synthesis Examples 11-16

<Production of Polyamic Acid Varnishes K to P>

Varnishes K to P of polyamic acid were produced in the same manner as in Synthesis Example 8 using the raw material compositions shown in Table 2. In addition, the parenthesis shows mol%.

<Table 2>

Example 1

0.50 g of varnish A and varnish H were respectively weighed out in the sample bottle, and NMP / BC = 1/1 (wt%) was added to make 1.67 g. About 3 weight% of polyamic acid solution of the said mixture was dripped on the transparent glass substrate, and it apply | coated by the spinner method (2,000 rpm, 15 second). After application | coating, the board | substrate was heated at 80 degreeC for 3 minutes and the solvent was evaporated, and linearly polarized light was irradiated across a polarizing plate (energy about 4J / cm <2> at 365nm). The board | substrate after light irradiation was heat-processed in oven at 23 degreeC for 10 minutes, and the orientation film A whose film thickness is about 70 nm was obtained. It was 2.0 nm when the retardation of this alignment film A was measured.

EXAMPLES 2-14

Using the varnish shown in Table 3, alignment films B to N were obtained in the same manner as in Example 1. The result of having measured the retardation is shown together with the result of Example 1.

<Table 3>

F ¹⁾ : Compound (30) having a weight ratio of 0.20 was further added to the same polymer component as used to obtain the alignment film E.

J ²⁾ : Under the same polymer conditions as the alignment film I, the firing conditions were changed to 200 ° C. for 10 minutes.

Comparative Example 1

Instead of the mixture of varnish B and varnish H, varnish B was used alone, the alignment film O was obtained by the same method as Example 1, and its retardation was measured. The result was 0.6 nm.

Comparative Example 2

Using varnish E instead of the mixture of varnish B and varnish H, the alignment film P was obtained by the same method as Example 1, and its retardation was measured. The result was 0.1 nm.

Comparative Example 3

Instead of the mixture of varnish F and varnish H, varnish F was used, the alignment film Q was obtained by the same method as Example 1, and its retardation was measured. The result was 1.3 nm.

Example 15

The UV-Vis spectrum of the alignment film B prepared in Example 2 was measured. The results are shown in FIG.

[Comparative Example 4]

The UV-Vis spectrum of the alignment film O prepared in Comparative Example 1 was measured. The result was shown in FIG. 1 with the data of the orientation film B. FIG.

When Examples and Comparative Examples 1 to 3 are compared, the alignment film of the present invention obtained by using the A component and the B component in combination has a larger retardation value, that is, the retardation value is increased compared to the alignment film obtained from only the A component. In order to make it, it turns out that it is important to add a liquid crystalline polymer to a photo-alignment agent. 1 shows that the alignment film B has a higher transmittance at 380 to 500 nm and less coloring than the alignment film O. FIG.

Example 16

Instead of the transparent glass substrate provided with the ITO electrode on one side of the glass substrate, the same method as in Example 1 was used except that the combinations of varnishes were the same as in the case of the alignment films B, E and F, respectively. Alignment film B ', E', and F 'were obtained. The two substrates on which the alignment films are formed on the ITO electrode are arranged so that the polarization directions of the linearly polarized light irradiated with respect to the respective alignment films are parallel, and the surfaces on which the alignment films are formed face each other, and between the alignment films that face each other. The air gap for inject | pouring a liquid crystal composition was formed and pasted, and liquid crystal cells B, E, and F (liquid crystal display element) with a cell thickness of 7 micrometers were assembled. Liquid crystal composition A shown below was injected into these cells.

<Liquid crystal composition A>

As a result of visual observation of the liquid crystal cells B, E and F, no so-called flow orientation in which the liquid crystals were arranged along the direction in which the liquid crystals flowed was observed at all. The liquid crystal cells B, E, and F were subjected to an isotropic treatment at 110 ° C. for 30 minutes, and cooled to room temperature. As a result of observing these liquid crystal cells B, E, and F with the microscope, the orientation defect of the liquid crystal was not observed in all. When the polarization microscope was made into a cross nicol state and the liquid crystal cells B, E, and F were rotated, a clear contrast state was observed. The pretilt angles, VHR (voltage retention), and ion density of these liquid crystal cells B, E, and F are shown in Table 4 below.

<Table 4>

Thus, when the orientation film of this invention is applied to the orientation film for liquid crystal display elements, it turns out that it has sufficient characteristics which can be endured practically.

Example 17

Varnishes G and K were weighed out by 1.60 g each, and NMP / BC = 1/1 (wt%) was added to the sample bottle to make 4.00 g. The mixed varnish having a polyamic acid concentration of about 4% by weight was added dropwise onto a transparent glass substrate provided with an ITO electrode on one side, and applied by a spinner method (1,600 rpm, 15 seconds). After the application, the substrate was heated at 80 ° C. for 3 minutes to evaporate the solvent, and the substrate plane was tilted at 45 degrees with respect to the light source and irradiated with unpolarized light (energy about 5 J / cm 2 at 365 nm). The substrate after light irradiation was heat-processed at 230 degreeC for 30 minutes, and the orientation film R whose film thickness is about 60 nm was obtained.

A liquid crystal cell having a cell thickness of 4 μm is formed by aligning two substrates on which the alignment film is formed on the ITO electrode with the surfaces on which the alignment film is formed to face each other, and forming a gap for injecting the liquid crystal composition between the alignment films that face each other. Assembled R. The joining direction of the board | substrate was performed by making the upper and lower sides the same on the opposite side when the direction perpendicular | vertical to the direction which inclined in the one direction to the left and right inclined up and down was made. Liquid crystal composition B shown below was injected into these cells.

This liquid crystal cell R was subjected to isotropic treatment at 110 ° C. for 30 minutes, and cooled to room temperature. As a result of observing this liquid crystal cell R under a microscope, even when the liquid crystal cell R was rotated in the cross nicol state, the dark state did not change, and no light leakage due to the alignment defect of the liquid crystal was observed. It was 89.1 degree when the pretilt angle of this liquid crystal cell R was measured by the said method. The direction in which the liquid crystal was inclined was the irradiation direction of light without polarization. Moreover, when voltage (5V) was applied to this liquid crystal cell R and observed with the polarization microscope, the schlieren structure by an orientation defect was not observed in the whole area | region of a cell, and favorable orientation was obtained. Moreover, clear contrast was observed when the liquid crystal cell R was rotated in this state. The VHR (voltage retention) of this liquid cell R was 97.9% at 30 Hz, 91.7% at 0.3 Hz, and ion density was 460 pC.

<Liquid crystal composition B>

Example 18

Liquid crystal in the same manner as in Example 17, except that the weight ratio of the mixture of varnish G and varnish K was changed from (varnish G) / (varnish K) = 1/1 to (varnish G) / (varnish K) = 1/9 Cell S was prepared. As a result of observing this liquid crystal cell S with a polarization microscope, even if the liquid crystal cell S was rotated in a cross nicol state, the dark state did not change and the light leakage by the orientation defect of the liquid crystal was not observed. It was 89.1 degree when the pretilt angle of this liquid crystal cell S was measured by the said method. Moreover, as a result of applying voltage (5V) to this liquid crystal cell S and observing with a polarization microscope, the sullene structure by an orientation defect was not observed in the whole area | region of a cell, and favorable orientation was obtained. Moreover, clear contrast was observed when the liquid crystal cell R was rotated in this state. The VHR (voltage retention) of this liquid cell S was 95.6% at 30 Hz, 88.7% at 0.3 Hz, and ion density was 820 pC.

For the Axel cell S, light resistance was performed by irradiating a light of a fluorescent lamp (8 watts) at a distance of 10 cm for 72 hours at an irradiation angle of 45 degrees. It was 89.1 degree as a result of measuring the pretilt angle after light irradiation.

Moreover, half of the liquid cell S was covered with aluminum foil, and the light resistance test was performed similarly to the above. As a result of observing the display portion under cross nicol by applying the voltage (3.2V) of the liquid crystal cell S after light irradiation, no change was observed in the light irradiation portion and the unlighted portion (FIG. 2).

[Examples 19-23]

Using the varnish shown in Table 5, liquid crystal cells T to X were obtained in the same manner as in Example 18. Table 5 shows the results of the vertical alignment, the pretilt angle, the display at the time of voltage application, the VHR, the ion density, and the light resistance test of the liquid crystal cells T to X.

<Table 5>

[Comparative Example 5]

Liquid crystal cell Y was produced in the same manner as in Example 17, except that the mixture of varnish G and varnish K was changed to varnish G. As a result of observing this liquid crystal cell Y with a polarization microscope, even if the liquid crystal cell Y was rotated in a cross nicol state, the dark state did not change, and the light leakage by the orientation defect of the liquid crystal was not observed. It was 89.1 degree when the pretilt angle of this liquid crystal cell Y was measured by the said method. Moreover, as a result of applying voltage (5V) to this liquid crystal cell Y and observing with a polarization microscope, the sullene structure by an orientation defect was not observed in the whole area | region of a cell, and favorable orientation was obtained. It was 89.0 degrees when the pretilt angle of this liquid crystal cell Y was measured.

The light resistance test of this liquid crystal cell Y was performed similarly to Example 18. It was 89.6 degrees when the pretilt angle after light irradiation was measured. As a result of observing the light irradiating portion and the non-irradiating portion, a clear difference was not observed (FIG. 3).

[Comparative Example 6]

Liquid crystal cell Z was prepared in the same manner as in Example 17, except that the mixture of varnish G and varnish K was changed to a mixture of varnish G and varnish P (varnish G / varnish P = 1/9; weight ratio). As a result of observing this liquid crystal cell Z with a polarizing microscope, even if the liquid crystal cell Z was rotated in a cross nicol state, the dark state did not change, and the light leakage by the orientation defect of the liquid crystal was not observed. It was 89.9 degrees when the pretilt angle of this liquid crystal cell Z was measured by the said method. Moreover, when the voltage (5V) was applied to this liquid crystal cell Z, and it observed with the polarization microscope, the orientation defect was observed in several places in the whole area | region of the cell.

1 is a UV-Vis spectrum of the alignment film B and the alignment film O measured in Example 15. FIG.

FIG. 2 is a photograph of liquid crystal cell S after the light resistance test performed in Example 18. FIG.

3 is a photograph of liquid crystal cell Y after the light resistance test performed in Comparative Example 4. FIG.

Claims (12)

A photoalignment agent containing at least one of the polymers having the photo-alignment ability as the A component, and containing at least one of the polymers having the liquid crystal temperature range in the range of 100 to 300 ° C as the B component. The method of claim 1, The said photo-component A is an at least 1 polymer chosen from the group which consists of a polyamic acid, a partially imidized polyamic acid, and a polyimide. The method of claim 1, A photoalignment agent, wherein the component A is a polymer having a photosensitive group in the main chain as at least one polymer selected from the group consisting of polyamic acid, partially imidized polyamic acid and polyimide. The method of claim 1, The component A is at least one polymer selected from the group consisting of polyamic acid, partially imidized polyamic acid and polyimide, and at least one photosensitive group represented by formulas (I) to (V) and (X) in the main chain At least one liquid crystalline polymer selected from the group consisting of a polyamic acid, a partially imidized polyamic acid, and a polyimide, wherein B component is two or more non-adjacent -CH ₂ --O-, Photoalignment agent, which is a polymer having a linear alkylene structure of 6 to 20 carbon atoms, which may be substituted with -NH-, -N (CH ₃ )-, or -Si (CH ₃ ) ₂ OSi (CH ₃ ) _2- :

Wherein R ¹ , R ² and R ³ are independently divalent groups. 5. The method of claim 4, The said A component is Formula (I-1)-Formula (I-3), Formula (II-1)-Formula (II-3), Formula (III-1), Formula (IV-1)-Formula (IV-) 3) and a photo-alignment agent which is a polymer obtained using at least one of the compound represented by Formula (V-1) and Formula (X-1)-Formula (X-8) as a raw material:

. 5. The method of claim 4, The photoalignment agent whose said B component is a polyimide which is a polyimide which has a structural unit represented by Formula (VI), or its precursor:

Wherein R ⁴ is one or two non-adjacent -CH ₂ -to -O-, -NH-, -N (CH ₃ )-, or -Si (CH ₃ ) ₂ OSi (CH ₃ ) _2- It may be a C2-C20 alkylene which may be substituted, the divalent group represented by Formula (VIII), or the divalent group represented by Formula (IX), and may differ for every structural unit; More than 60% of the total number of units is one in which R ⁴ is or two non-adjacent two -CH ₂ -is -O-, -NH-, -N (CH ₃ )-, or -Si (CH ₃ ) ₂ OSi (CH _{3) 2} - Im may be substituted carbon atoms, alkylene of 6 to 20 in a structural unit with:

In formula (VIII), X ¹ and X ² are a single bond, —O—, —COO—, —OCO—, —NH—, —CONH—, or alkylene having 1 to 12 carbon atoms; G ¹ and G ² are divalent groups containing 1 to 3 rings selected from a single bond or an aromatic ring having 6 to 12 carbon atoms and an alicyclic ring having 3 to 12 carbon atoms; R ⁵ is hydrogen, fluorine, —CN, —OH, or alkyl having 1 to 30 carbon atoms, perfluoroalkyl or alkoxy; When X ¹ , G ¹ , X ² and G ² are all single bonds, R ⁵ is alkyl, perfluoroalkyl or alkoxy having 3 to 30 carbon atoms, G ² is a single bond and X ² is not a single bond; If not alkylene, R ⁵ is hydrogen or alkyl of 3 to 30 carbon atoms, and when G ¹ and G ² are both single bonds, the sum of the carbon numbers of X ¹ , X ² and R ⁵ is 3 or more:

In formula (IX), R ⁶ is hydrogen or alkyl having 1 to 12 carbon atoms; Ring B is 1,4-phenylene in which arbitrary hydrogen may be substituted by alkyl having 1 to 4 carbon atoms, or 1,4-cyclohexylene in which arbitrary hydrogen may be substituted by alkyl having 1 to 4 carbon atoms ego; X ⁰ is a single bond or alkylene having 1 to 5 carbon atoms; s is an integer of 0 to 3; When s is 2, two rings B may be the same or different, and two X ⁰ may be the same or different, and when s is 3, three or any two rings B may be the same or different. And three or any two X ⁰ may be the same or different; Z ¹ and Z ² are independently a single bond, —CH ₂ —, —CH ₂ CH ₂ — or —O—; t1 and t2 are independently integers of 0 to 3; when t1 is 2, two Z ¹ may be the same or different; when t1 is 3, three or any two Z ¹ may be the same or different; when t2 is 2, the two Z ² may be the same or different; When t2 is 3, three or any two Z ² may be the same or different. 5. The method of claim 4, The said A component is Formula (I-1)-Formula (I-3), Formula (II-1)-Formula (II-3), Formula (III-1), Formula (IV-1)-Formula (IV-) 3), a polymer obtained by using at least one of the compounds represented by formulas (V-1) and (X-1) to (X-8) as raw materials, wherein the B component is represented by formula (VI). A photoalignment agent, which is a polyamic acid having a polyimide or a precursor thereof with a structural unit to be formed:

Wherein R ⁴ is one or two non-adjacent -CH ₂ -to -O-, -NH-, -N (CH ₃ )-, or -Si (CH ₃ ) ₂ OSi (CH ₃ ) _2- It may be a C2-C20 alkylene which may be substituted, the divalent group represented by Formula (VIII), or the divalent group represented by Formula (IX), and may differ for every structural unit; More than 60% of the total number of units is one in which R ⁴ is or two non-adjacent two -CH ₂ -is -O-, -NH-, -N (CH ₃ )-, or -Si (CH ₃ ) ₂ OSi (CH _{3) 2} - Im may be substituted carbon atoms, alkylene of 6 to 20 in a structural unit with:

In formula (VIII), X ¹ and X ² are a single bond, —O—, —COO—, —OCO—, —NH—, —CONH—, or alkylene having 1 to 12 carbon atoms; G ¹ and G ² are divalent groups containing 1 to 3 rings selected from a single bond or an aromatic ring having 6 to 12 carbon atoms and an alicyclic ring having 3 to 12 carbon atoms; R ⁵ is hydrogen, fluorine, —CN, —OH, or alkyl having 1 to 30 carbon atoms, perfluoroalkyl or alkoxy; When X ¹ , G ¹ , X ² and G ² are all single bonds, R ⁵ is alkyl, perfluoroalkyl or alkoxy having 3 to 30 carbon atoms, G ² is a single bond and X ² is not a single bond; If not alkylene, R ⁵ is hydrogen or alkyl of 3 to 30 carbon atoms, and when G ¹ and G ² are both single bonds, the sum of the carbon numbers of X ¹ , X ² and R ⁵ is 3 or more:

In formula (IX), R ⁶ is hydrogen or alkyl having 1 to 12 carbon atoms; Ring B is 1,4-phenylene in which arbitrary hydrogen may be substituted by alkyl having 1 to 4 carbon atoms, or 1,4-cyclohexylene in which arbitrary hydrogen may be substituted by alkyl having 1 to 4 carbon atoms ego; X ⁰ is a single bond or alkylene having 1 to 5 carbon atoms; s is an integer of 0 to 3; When s is 2, two rings B may be the same or different, and two X ⁰ may be the same or different, and when s is 3, three or any two rings B may be the same or different. And three or any two X ⁰ may be the same or different; Z ¹ and Z ² are independently a single bond, —CH ₂ —, —CH ₂ CH ₂ — or —O—; t1 and t2 are independently integers of 0 to 3; when t1 is 2, two Z ¹ may be the same or different; when t1 is 3, three or any two Z ¹ may be the same or different; when t2 is 2, the two Z ² may be the same or different; When t2 is 3, three or any two Z ² may be the same or different. The method of claim 7, wherein R <^4> in said Formula (VI) may be different for every structural unit as a C2-C20 alkylene or a bivalent group represented by Formula (VIII-1); 60% or more of the total number of structural units is a structural unit whose R <^4> is a C6-C20 alkylene:

Wherein ring B ¹ and ring B ² are independently a single bond or 1,4-cyclohexylene, G ³ is a single bond or —CH ₂ CH ₂ —, and R ⁷ is hydrogen or alkyl of 1 to 20 carbon atoms . The method of claim 1, The photo-alignment agent whose ratio of the said A component based on the total weight of the said A component and the said B component is 10 to 90 weight%. The liquid crystal aligning film manufactured using the photo-alignment agent in any one of Claims 1-9. The liquid crystal display element manufactured using the photoalignment film of Claim 10. A film having a photo-alignment capability as a component A, a photo-alignment agent containing a polymer having a liquid crystal temperature range as a component B in a range of 100 to 300 ° C. is applied to a substrate and formed into a film, irradiated with light to orient the film. And heating treatment to raise the temperature to the liquid crystal temperature of the component B is carried out.

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