JP5407394B2 - Photo-alignment agent, alignment film, and liquid crystal display device using the same - Google Patents

Description

  The present invention relates to an alignment film, a method for producing the alignment film, 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 for notebook computers and desktop personal computers, viewfinders for video cameras, and projection displays. Recently, liquid crystal display devices have also been used for televisions. Furthermore, it is also used as an optoelectronic-related element such as an optical printer head, an optical Fourier transform element, or a light valve. As a conventional liquid crystal display element, a display element using a nematic liquid crystal is mainly used, and the alignment direction of the liquid crystal in the vicinity of one substrate and the liquid crystal in the vicinity of the other substrate are twisted at an angle of 90 degrees. (Twisted Nematic) mode, STN (Super Twisted Nematic) mode in which the orientation direction is twisted at an angle of 180 degrees or more, and so-called TFT (Thin-film-transistor) mode liquid crystal display devices using thin film transistors Has been.

  However, these liquid crystal display elements have a narrow viewing angle at which an image can be properly viewed, and when viewed from an oblique direction, luminance and contrast may be reduced, and luminance inversion may occur in a halftone. In recent years, this viewing angle problem has been caused by a TN type liquid crystal display element using an optical compensation film, a MVA (Multi-domain Vertical Alignment) mode in which vertical alignment and a technique of a protruding structure are used in combination (for example, see Patent Document 1). ) Or lateral electric field type IPS (In-Plane Switching) mode (see, for example, Patent Document 2).

  The development of the technology of the liquid crystal display element has been achieved not only by improving the drive system and the element structure, but also by improving the components used for the display element. Among the constituent members used in display elements, the liquid crystal alignment film is one of the important elements related to the display quality of the liquid crystal display element, and the role of the liquid crystal alignment film is increasing as the quality of the display element increases. It has become important year after year.

  In such a liquid crystal alignment film, it is necessary to uniformly control the molecular arrangement of the liquid crystal for the uniform display characteristics of the liquid crystal display element. For this purpose, the liquid crystal molecules on the substrate are uniformly aligned in one direction. Furthermore, it is required to develop a certain tilt angle (pretilt angle) from the substrate surface. Thus, a liquid crystal alignment film that uniformly aligns the directions of liquid crystal molecules on a substrate is an important and indispensable technique in the manufacturing process of a liquid crystal display element.

  The liquid crystal alignment film is prepared from a liquid crystal alignment agent. The liquid crystal aligning agent mainly used at present is a solution in which polyamic acid or soluble polyimide is dissolved in an organic solvent. After applying such a solution to a substrate, a polyimide-based liquid crystal alignment film is formed by film formation by means such as heating. Various liquid crystal aligning agents other than polyamic acid are also being studied, but they are almost practical in terms of heat resistance, chemical resistance (liquid crystal resistance), coating properties, liquid crystal alignment properties, electrical properties, optical properties, display properties, etc. It has not been converted.

  Industrially, a rubbing method that is simple and capable of high-speed processing of a large area is widely used as an alignment processing method. The rubbing method is a process of rubbing the surface of the liquid crystal alignment film in one direction using a cloth in which fibers of nylon, rayon, polyester, or the like are planted, and this makes it possible to obtain uniform alignment of liquid crystal molecules. However, problems such as dust generation by static rubbing and generation of static electricity have been pointed out.

So far, the following two have been proposed as the alignment mechanism of the liquid crystal on the liquid crystal alignment film subjected to the alignment treatment by the rubbing treatment.
(1) Surface shape effect of liquid crystal alignment film caused by microgroove generated by rubbing treatment (2) Intermolecular interaction between liquid crystal alignment film uniaxially aligned by rubbing treatment and liquid crystal monolayer in contact with this liquid crystal alignment film Then, it was 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, with respect to a photo-alignment method in which alignment treatment is performed by irradiating light, many alignment mechanisms such as a photolysis method, a photoisomerization method, a photo-dimerization method, a photo-crosslinking method have been proposed (for example, Non-Patent Document 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 (2) acts as the alignment mechanism of liquid crystal. In addition, since the photo-alignment treatment method is non-contact, the generation of dust and static electricity is less in principle than the rubbing treatment.

  Accordingly, by using a liquid crystal alignment film having a good alignment property that has been subjected to an alignment treatment by a photo-alignment method in particular, the molecular alignment state of the liquid crystal monolayer in contact with the liquid crystal alignment film is controlled to provide a liquid crystal display element. It can be expected to improve performance.

Japanese Patent No. 2947350 Japanese Patent No. 2940354 JP 2005-275364 A Japanese Patent Laid-Open No. 11-15001

Liquid Crystal, Vol. 3, No. 4, 262 pages, 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 diligent research and development, the inventors of the present invention can improve the photo-alignment property by blending a polymer having liquid crystal properties with the photo-alignment agent. The present invention has been completed by finding that the coloring of can be reduced. The photo-alignment agent of the present invention is shown in the following item [1].
[1] A photoalignment agent containing at least one polymer having photoalignment ability as an A component and containing at least one polymer having a liquid crystal temperature range in the range of 100 to 300 ° C. as a B component.

  When the photo-alignment agent of the present invention is used as, for example, a liquid crystal aligning agent, a film having a liquid crystal orientation equivalent to or higher than that obtained by rubbing can be obtained by light irradiation for a short time. Moreover, the coloring of the film can be significantly reduced. Furthermore, when light from a backlight or the like is irradiated, a photo-alignment film having no alignment change due to the light can be obtained.

UV-Vis spectrum of alignment film B and alignment film O measured in Example 15 Photograph of liquid crystal cell S after the light resistance test performed in Example 18 Photograph of liquid crystal cell Y after the light resistance test performed in Comparative Example 4

  Terms used in the present invention will be described. The compound represented by the formula (I-1) may be described as the compound (I-1). Similarly, compounds represented by other formulas may be abbreviated. “Arbitrary” used in defining a chemical structural formula indicates that not only the position but also the number is arbitrary. In the chemical structural formula, a group in which a letter (for example, B) is surrounded by a hexagon means a group having a ring structure (ring B), and a group Me means methyl.

The present invention comprises the above item [1] and the following items [2] to [12].
[2] The photoalignment agent according to item [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] Item [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 the polymer has a photosensitive group in its main chain. The photo-alignment agent described in 1.

ここに、Ｒ^１、Ｒ^２およびＲ^３は独立して芳香族の２価の基である。 [4] The component A is at least one polymer selected from the group consisting of a polyamic acid, a partially imidized polyamic acid, and a polyimide, and this polymer is included in the main chain of the formula (I) to the formula (V) and the formula ( X) a polymer having at least one photosensitive group, and B component is at least one liquid crystalline polymer selected from the group consisting of polyamic acid, partially imidized polyamic acid and polyimide, The polymer is one or two non-adjacent to the main chain —CH ₂ — is —O—, —NH—, —N (CH ₃ ) —, or —Si (CH ₃ ) ₂ OSi (CH ₃ ) ₂ —. The photo-alignment agent according to item [1], which is a polymer having a linear alkylene structure having 6 to 20 carbon atoms that may be replaced:

Here, R ¹ , R ² and R ³ are independently aromatic divalent groups.

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

ここに、Ｒ^４は１つまたは隣接しない２つの−ＣＨ_２−が−Ｏ−、−ＮＨ−、−Ｎ（ＣＨ_３）−、または−Ｓｉ（ＣＨ_３）_２ＯＳｉ（ＣＨ_３）_２−で置き換えられてもよい炭素数２〜２０のアルキレン、式（VIII）で表される２価の基、または式（IX）で表される２価の基であり、構成単位ごとに異なってもよく；そして、全構成単位数の６０％以上はＲ^４が１つまたは隣接しない２つの−ＣＨ_２−が−Ｏ−、−ＮＨ−、−Ｎ（ＣＨ_３）−、または−Ｓｉ（ＣＨ_３）_２ＯＳｉ（ＣＨ_３）_２−で置き換えられてもよい炭素数６〜２０のアルキレンである構成単位である。

（ここに、Ｘ^１およびＸ^２は単結合、−Ｏ−、−ＣＯＯ−、−ＯＣＯ−、−ＮＨ−、−ＣＯＮＨ−、または炭素数１〜１２のアルキレンであり；Ｇ^１およびＧ^２は単結合、または炭素数６〜１２の芳香族環および炭素数３〜１２の脂環式環から選ばれる１〜３個の環を含む２価の基であり；Ｒ^５は水素、フッ素、−ＣＮ、−ＯＨ、または炭素数１〜３０のアルキル、ペルフルオロアルキルもしくはアルコキシであり；そして、Ｘ^１、Ｇ^１、Ｘ^２およびＧ^２の全てが単結合である場合は、Ｒ^５は炭素数３〜３０のアルキル、ペルフルオロアルキルもしくはアルコキシであり、Ｇ^２が単結合でありＸ^２が単結合でもなくアルキレンでもない場合は、Ｒ^５は水素または炭素数３〜３０のアルキルであり、Ｇ^１およびＧ^２が共に単結合である場合は、Ｘ^１、Ｘ^２およびＲ^５の炭素数の合計が３以上である。）

（ここに、Ｒ^６は水素または炭素数１〜１２のアルキルであり；環Ｂは任意の水素が炭素数１〜４のアルキルで置き換えられてもよい１，４−フェニレン、または任意の水素が炭素数１〜４のアルキルで置き換えられてもよい１，４−シクロへキシレンであり；Ｘ^０は単結合または炭素数１〜５のアルキレンであり；ｓは０〜３の整数であり；ｓが２であるとき、２つの環Ｂは同じであっても異なってもよく、２つのＸ^０も同じであっても異なってもよく；ｓが３であるとき、３つのまたは任意の２つの環Ｂは同じであっても異なってもよく、３つのまたは任意の２つのＸ^０も同じであっても異なってもよく；Ｚ^１およびＺ^２は独立して単結合、−ＣＨ_２−、−ＣＨ_２ＣＨ_２−または−Ｏ−であり；ｔ１およびｔ２は独立して０〜３の整数であり；ｔ１が２であるとき、２つのＺ^１は同じであっても異なってもよく；ｔ１が３であるとき、３つのまたは任意の２つのＺ^１は同じであっても異なってもよく；ｔ２が２であるとき、２つのＺ^２は同じであっても異なってもよく；ｔ２が３であるとき、３つのまたは任意の２つのＺ^２は同じであっても異なってもよい。） [6] The photoalignment agent according to item [4], wherein the B component is a polyimide having a structural unit represented by formula (VI) or a polyamic acid of a precursor thereof.

Here, R ⁴ is one or two non-adjacent —CH ₂ — being —O—, —NH—, —N (CH ₃ ) —, or —Si (CH ₃ ) ₂ OSi (CH ₃ ) ₂ —. An alkylene having 2 to 20 carbon atoms that may be substituted, a divalent group represented by the formula (VIII), or a divalent group represented by the formula (IX), and may be different for each structural unit And 60% or more of the total number of structural units is one in which R ⁴ is one or two non-adjacent —CH ₂ — is —O—, —NH—, —N (CH ₃ ) —, or —Si (CH ₃ ); ₂ is a structural unit of alkylene having 6 to 20 carbon atoms which may be replaced by OSi (CH ₃ ) ₂ —.

(Where 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 A single bond or a divalent group containing 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, fluorine,- CN, —OH, or alkyl having 1 to 30 carbons, perfluoroalkyl or alkoxy; and when all of X ¹ , G ¹ , X ² and G ² are a single bond, R ⁵ is carbon 3 R ⁵ is hydrogen or alkyl of 3 to 30 carbons when G ² is a single bond and X ² is neither a single bond nor an alkylene, and G ¹ and G ² are both a single bond If ^it, the total number of carbon atoms in X 1, ^{X 2} and ^{R 5} is 3 or more.)

(Wherein R ⁶ is hydrogen or alkyl having 1 to 12 carbons; ring B is 1,4-phenylene in which any hydrogen may be replaced by alkyl having 1 to 4 carbons, or any hydrogen is 1,4-cyclohexylene which may be replaced by alkyl having 1 to 4 carbon atoms; X ⁰ is a single bond or alkylene having 1 to 5 carbon atoms; s is an integer of 0 to 3; When is 2, the two rings B may be the same or different, and the two X ⁰ may be the same or different; when s is 3, three or any two Ring 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- and is; t1 and t2 are independently 0-3 When t1 is 2, the two Z ¹ may be the same or different; an integer when t1 is 3, three or any two of Z ¹ are different and can be the same When t2 is 2, 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 Good.)

ここに、Ｒ^４は１つまたは隣接しない２つの−ＣＨ_２−が−Ｏ−、−ＮＨ−、−Ｎ（ＣＨ_３）−、または−Ｓｉ（ＣＨ_３）_２ＯＳｉ（ＣＨ_３）_２−で置き換えられてもよい炭素数２〜２０のアルキレン、式（VIII）で表される２価の基、または式（IX）で表される２価の基であり、構成単位ごとに異なってもよく；そして、全構成単位数の６０％以上はＲ^４が１つまたは隣接しない２つの−ＣＨ_２−が−Ｏ−、−ＮＨ−、−Ｎ（ＣＨ_３）−、または−Ｓｉ（ＣＨ_３）_２ＯＳｉ（ＣＨ_３）_２−で置き換えられてもよい炭素数６〜２０のアルキレンである構成単位である。

（ここに、Ｘ^１およびＸ^２は独立して単結合、−Ｏ−、−ＣＯＯ−、−ＯＣＯ−、−ＮＨ−、−ＣＯＮＨ−、または炭素数１〜１２のアルキレンであり；Ｇ^１およびＧ^２は独立して単結合、または炭素数６〜１２の芳香族環および炭素数３〜１２の脂環式環から選ばれる１〜３個の環を含む２価の基であり；Ｒ^５は水素、フッ素、−ＣＮ、−ＯＨ、または炭素数１〜３０のアルキル、ペルフルオロアルキルもしくはアルコキシであり；そして、Ｘ^１、Ｇ^１、Ｘ^２およびＧ^２の全てが単結合である場合は、Ｒ^５は炭素数３〜３０のアルキル、ペルフルオロアルキルもしくはアルコキシであり、Ｇ^２が単結合でありＸ^２が単結合でもなくアルキレンでもない場合は、Ｒ^５は水素または炭素数３〜３０のアルキルであり、Ｇ^１およびＧ^２が共に単結合である場合は、Ｘ^１、Ｘ^２およびＲ^５の炭素数の合計が３以上である。）

（ここに、Ｒ^６は水素または炭素数１〜１２のアルキルであり；環Ｂは任意の水素が炭素数１〜４のアルキルで置き換えられてもよい１，４−フェニレン、または任意の水素が炭素数１〜４のアルキルで置き換えられてもよい１，４−シクロへキシレンであり；Ｘ^０は単結合または炭素数１〜５のアルキレンであり；ｓは０〜３の整数であり；ｓが２であるとき、２つの環Ｂは同じであっても異なってもよく、２つのＸ^０も同じであっても異なってもよく；ｓが３であるとき、３つのまたは任意の２つの環Ｂは同じであっても異なってもよく、３つのまたは任意の２つのＸ^０も同じであっても異なってもよく；Ｚ^１およびＺ^２は独立して単結合、−ＣＨ_２−、−ＣＨ_２ＣＨ_２−または−Ｏ−であり；ｔ１およびｔ２は独立して０〜３の整数であり；ｔ１が２であるとき、２つのＺ^１は同じであっても異なってもよく；ｔ１が３であるとき、３つのまたは任意の２つのＺ^１は同じであっても異なってもよく；ｔ２が２であるとき、２つのＺ^２は同じであっても異なってよく；ｔ２が３であるとき、３つのまたは任意の２つのＺ^２は同じであっても異なってよい。） [7] A component is a formula (I-1)-a formula (I-3), a formula (II-1)-a formula (II-3), a formula (III-1), a formula (IV-1)-a formula ( IV-3), a polymer obtained by using at least one of the compounds represented by formula (V-1) and formula (X-1) to formula (X-8) as a raw material, and component B is represented by formula The photo-alignment agent according to item [4], which is a polyimide having a structural unit represented by (VI) or a polyamic acid of a precursor thereof.

Here, R ⁴ is one or two non-adjacent —CH ₂ — being —O—, —NH—, —N (CH ₃ ) —, or —Si (CH ₃ ) ₂ OSi (CH ₃ ) ₂ —. An alkylene having 2 to 20 carbon atoms that may be substituted, a divalent group represented by the formula (VIII), or a divalent group represented by the formula (IX), and may be different for each structural unit And 60% or more of the total number of structural units is one in which R ⁴ is one or two non-adjacent —CH ₂ — is —O—, —NH—, —N (CH ₃ ) —, or —Si (CH ₃ ); ₂ is a structural unit of alkylene having 6 to 20 carbon atoms which may be replaced by OSi (CH ₃ ) ₂ —.

(Wherein X ¹ and X ² are each independently a single bond, —O—, —COO—, —OCO—, —NH—, —CONH—, or alkylene having 1 to 12 carbons; G ¹ and G ² is independently a single bond or a divalent group containing 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, fluorine, —CN, —OH, or alkyl having 1 to 30 carbons, perfluoroalkyl or alkoxy; and when all of X ¹ , G ¹ , X ² and G ² are single bonds, R ⁵ is alkyl, perfluoroalkyl or alkoxy having 3 to 30 carbon atoms, and when G ² is a single bond and X ² is neither a single bond nor alkylene, R ⁵ is hydrogen or alkyl having 3 to 30 carbon atoms. in it, ^{G 1} and G If is both a single ^bond, the total number of carbon atoms of X 1, ^{X 2} and ^{R 5} is 3 or more.)

(Wherein R ⁶ is hydrogen or alkyl having 1 to 12 carbons; ring B is 1,4-phenylene in which any hydrogen may be replaced by alkyl having 1 to 4 carbons, or any hydrogen is 1,4-cyclohexylene which may be replaced by alkyl having 1 to 4 carbon atoms; X ⁰ is a single bond or alkylene having 1 to 5 carbon atoms; s is an integer of 0 to 3; When is 2, the two rings B may be the same or different, and the two X ⁰ may be the same or different; when s is 3, three or any two Ring 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- and is; t1 and t2 are independently 0-3 When t1 is 2, the two Z ¹ may be the same or different; an integer when t1 is 3, three or any two of Z ¹ are different and can be the same When t2 is 2, the two Z ² may be the same or different; when t2 is 3, the three or any two Z ² may be the same or different. )

（ここに、環Ｂ^１および環Ｂ^２は独立して単結合または１，４−シクロヘキシレンであり、Ｇ^３は単結合または−ＣＨ_２ＣＨ_２−であり、そしてＲ^７は水素または炭素数１〜２０のアルキルである。） [8] R ⁴ in the formula (VI) is an alkylene having 2 to 20 carbon atoms or a divalent group represented by the formula (VIII-1), and may be different for each structural unit; The photo-alignment agent according to item [7], wherein R ⁴ having 60% or more of the number is a structural unit of alkylene having 6 to 20 carbon atoms.

(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 carbon number. 1-20 alkyl.)

[9] The photoalignment agent according to any one of [1] to [8], wherein the ratio 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 liquid crystal alignment film according to the item [10].

[12] A photo-alignment agent containing a polymer having photo-alignment ability as an A component and a polymer having a liquid crystal temperature range in the range of 100 to 300 ° C. as a B component is applied to a substrate to form a film. A method for producing a liquid crystal alignment film, comprising: aligning the film by irradiation and then performing a heat treatment to raise a temperature to a liquid crystal temperature of a B component.

  The component A of the photo-alignment agent of the present invention is important not only for inducing anisotropy in the film by light but also for maintaining the anisotropy when the photo-alignment agent of the present invention is formed into a film. is there. For example, when using a polyamic acid as the A component and adopting an alignment film forming method described below that improves the photo-orientation by firing after irradiation with light, so as not to cause a decrease in anisotropy due to heating, It is preferable to select a component that is non-liquid crystalline at a temperature range of 100 to 300 ° C., which is a temperature range of firing usually performed. For the same reason, it is more preferable to select a component that does not have a glass transition point (Tg) at 300 ° C. or lower. Specifically, the A component is preferably a polyamic acid having photo-alignment ability, a polymer obtained by partially imidizing this polyamic acid, or a polyimide obtained by completely dehydrating and cyclizing this polyamic acid, and is sensitive to the main chain. More preferred are those polymers having groups.

  There is no particular limitation on the photosensitive group possessed by the polymer having photoalignment ability, that is, the photoalignable polymer, and all known photosensitive groups can be selected. Examples of known photosensitive groups include azobenzene derivatives, maleimide derivatives, chalcone derivatives, cinnamic acid derivatives, 1,2-vinylene derivatives, and 1,2-acetylene derivatives, spiropyran derivatives, spirobenzopyran derivatives and fulgide derivatives Photosensitive group.

The photo-alignment agent of the present invention is a non-liquid crystalline polyamic acid having at least one photosensitive group represented by the formulas (I) to (V) and (X) in the main chain, and this polyamic acid is partially used. It is preferable to contain as component A at least one polymer selected from the group consisting of a polymer obtained by imidizing the polyamic acid and a polyimide obtained by completely dehydrating and cyclizing the polyamic acid.

R ¹ , R ² and R ³ in the formulas (I) to (V) are independently an aromatic divalent group. Preferred examples of the aromatic divalent group include 1,4-phenylene, 1,3-phenylene, 2-methyl-1,4-phenylene, 2-methyl-1,3-phenylene, and 4,4′-biphenylene. And diphenylmethane-4,4′-diyl, where any hydrogen in these rings may be replaced by fluorine or chlorine. Of these groups, 1,4-phenylene and 1,3-phenylene are more preferred, and 1,4-phenylene is most preferred.

  By selecting the photosensitive groups represented by the formulas (I) to (V) and (X), the characteristics of the photo-alignment agent of the present invention, which is large in photo-alignment and less colored, can be exhibited to the maximum. Is possible. There are two isomers of cis or trans in the double bond of the photosensitive group of formula (III) and formula (V), and any of these isomers may be used for the photoalignment agent of the present invention. Absent.

  In order to obtain a polyamic acid having at least one photosensitive group represented by the formulas (I) to (V) and (X) in the main chain, a diamine or / and carboxylic acid having such a photosensitive group A dianhydride may be used as a raw material. In order to obtain particularly high photo-alignment properties, it is preferable to use a raw material having a photosensitive group in diamine.

Among the diamines having photosensitive groups represented by formulas (I) to (V), particularly preferred examples include diamines of formula (I-1) to formula (V-1).

Preferable examples of the diamine or tetracarboxylic dianhydride having a photosensitive group represented by the formula (X) are shown below.

  Depending on the required properties of the alignment film, the diamine having a photosensitive group and a known diamine having no photosensitive group can be used in combination when the polymer as the component A of the present invention is produced. For example, when an alignment film is used as an alignment film for a nematic liquid crystal composition in a liquid crystal display application, it has a high voltage holding ratio (VHR) and exhibits characteristics such as hardly causing seizure. Diamines can be used.

式（２）において、Ａ^１、Ａ^２、Ａ^３およびＡ^４は独立してシクロへキシレンまたはフェニレンであり；Ｘ^３およびＸ^４は独立して単結合、炭素数１〜５のアルキレンまたは−Ｏ−であり；Ｘ^５およびＸ^６は独立して単結合、−ＣＨ_２−、−ＣＨ_２ＣＨ_２−、−Ｏ−または−Ｓ−であり；Ｙ^１は−ＣＨ_２−、−Ｃ（Ｒ^１１）（Ｒ^１２）−、−ＣＯ−または−ＳＯ_２−であり、Ｒ^１１およびＲ^１２は独立して水素、炭素数１〜１２のアルキル、または炭素数１〜１２のパーフルオロアルキルであり；ｍ１、ｍ２、ｍ３、ｍ４およびｎは独立して０または１である。そして、上記のシクロヘキシレンおよびフェニレンにおいて、任意の水素は炭素数１〜４のアルキルまたはベンジルで置き換えられてもよく、これらの置換基の結合位置は任意である。シクロヘキシレンおよびフェニレンの遊離基の位置も任意であるが、１，３−または１，４−が好ましく、１，４−が最も好ましい。 Suitable examples of such known diamines include diamines represented by the formula (2).

In formula (2), A ¹ , A ² , A ³ and A ⁴ are each independently cyclohexylene or phenylene; X ³ and X ⁴ are each independently a single bond, alkylene having 1 to 5 carbon atoms or — X ⁵ and X ⁶ are each 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 —, wherein R ¹¹ and R ¹² are independently hydrogen, alkyl having 1 to 12 carbons, or perfluoroalkyl having 1 to 12 carbons. Yes; m1, m2, m3, m4 and n are independently 0 or 1; And in said cyclohexylene and phenylene, arbitrary hydrogen may be substituted by a C1-C4 alkyl or benzyl, and the coupling | bonding position of these substituents is arbitrary. The position of the free radical of cyclohexylene and phenylene is also arbitrary, but 1,3- or 1,4- is preferable, and 1,4- is most preferable.

Preferred examples of the diamine represented by the formula (2) are shown below.

  Among these, from the viewpoint of imparting a high VHR to the liquid crystal alignment film and suppressing the image sticking phenomenon, the formulas (2-6) to (2-23), the formula (2-38), the formula (2-39), and the formula (2-44), Formula (2-45), Formula (2-49), or a diamine represented by Formula (2-50) to Formula (2-54) is more preferable, and Formula (2-6), Formula (2-7), Formula (2-11), Formula (2-12) to Formula (2-16), Formula (2-19) to Formula (2-24), or Formula (2-51) The diamine represented is more preferred.

  The ratio of the diamine having no photosensitive group in the present invention can be arbitrarily selected according to the desired orientation and electrical characteristics. However, since the orientation decreases when the use ratio of these diamines is large, this use ratio ranges from 0 to 50 mol% with respect to the total amount of diamine used when synthesizing the polyimide or polyamic acid as the component A. It is preferable that it is 0-30 mol%.

Another example of a 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 formula (3) or formula (4).

In Formula (3), X ¹ and X ² are each independently a single bond, —O—, —COO—, —OCO—, —NH—, —CONH—, or alkylene having 1 to 12 carbons; G ¹ And G ^{2 each} independently represents a single bond or a divalent group containing 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, fluorine, -CN, -OH, or alkyl having 1 to 30 carbons, perfluoroalkyl or alkoxy. ^However, if all of X ^1, G 1, ^{X 2} and ^{G 2} is a single bond, ^{R 5} is alkyl of 3 to 30 carbon atoms, be a perfluoroalkyl or alkoxy; A ^{G 2} is a single bond X ^{When 2} is neither a single bond nor alkylene, R ⁵ is hydrogen or alkyl; and when G ¹ and G ² are both single bonds, the total number of carbon atoms of X ¹ , X ² and R ⁵ Is 3 or more.

In the above formula (3), the two amino groups are bonded to the carbon of the benzene ring, but the bonding position relationship between the two amino groups is preferably meta or para. The two amino groups are preferably bonded to the 3rd and 5th positions or the 2nd and 5th positions, respectively, when the bonding position of X1 is the ^1st position. It is particularly preferable.

式（４）において、Ｒ^５は水素または炭素数１〜１２のアルキルであり；環Ｂは任意の水素が炭素数１〜４のアルキルで置き換えられてもよい１，４−フェニレン、または任意の水素が炭素数１〜４のアルキルで置き換えられてもよい１，４−シクロへキシレンであり；Ｘ^０は単結合または炭素数１〜５のアルキレンであり；ｓは０〜３の整数であり；ｓが２であるとき、２つの環Ｂは同じであっても異なってもよく、２つのＸ^０も同じであっても異なってもよく；ｓが３であるとき、３つのまたは任意の２つの環Ｂは同じであっても異なってもよく、３つのまたは任意の２つのＸ^０も同じであっても異なってもよく；Ｚ^１およびＺ^２は独立して単結合、−ＣＨ_２−、−ＣＨ_２ＣＨ_２−または−Ｏ−であり；ｔ１およびｔ２は独立して０〜３の整数であり；ｔ１が２であるとき、２つのＺ^１は同じであっても異なってもよく；ｔ１が３であるとき、３つのまたは任意の２つのＺ^１は同じであっても異なってもよく；ｔ２が２であるとき、２つのＺ^２は同じであっても異なってもよく；ｔ２が３であるとき、３つのまたは任意の２つのＺ^２は同じであっても異なってもよい。

In formula (4), R ⁵ is hydrogen or alkyl having 1 to 12 carbons; ring B is 1,4-phenylene in which any hydrogen may be replaced by alkyl having 1 to 4 carbons, or any Hydrogen is 1,4-cyclohexylene optionally substituted with alkyl having 1 to 4 carbons; X ⁰ is a single bond or alkylene having 1 to 5 carbons; s is an integer of 0 to 3 When s is 2, the two rings B may be the same or different; the 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- and is; t1 and t2 are independently When t1 is 2, the two Z ¹ may be the same or different; an integer from 0 to 3 when t1 is 3, three or any two of Z ¹ are the same When t2 is 2, the two Z ² may be the same or different; when t2 is 3, three or any two Z ² are the same and May be different.

Preferred examples of the diamine represented by the formula (3) are shown below.

In the formula (3-1) to the formula (3-25), R ²⁰ is alkyl or alkoxy having 1 to ²⁰ carbons, preferably alkyl having 5 to 16 carbons. R ²¹ is alkyl or alkoxy having 1 to 20 carbons, preferably alkyl having 3 to 10 carbons. 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 alkyl or alkoxy having 3 to 20 carbon atoms, preferably alkyl having 5 to 12 carbon atoms. R ²⁵ is alkyl having 1 to 20 carbons or alkoxy, preferably alkyl having 3 to 10 carbons.

  Among these diamines, more preferred examples are represented by each of formula (3-1), formula (3-2), formula (3-4), formula (3-5), and formula (3-6). More preferred examples are diamines represented by formula (3-1) and formula (3-2), respectively.

Preferred examples of the diamine represented by the formula (4) are shown below.

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

  The ratio of the diamine having a side chain group in the present invention can be arbitrarily selected according to the target orientation, electrical characteristics, or pretilt angle. In particular, in order to express a pretilt angle of 2 degrees or more, the use ratio is preferably 5 to 70 mol% in the total amount of diamine used in producing the polymer of component A, and 10 to 50 mol% More preferably.

式（１５）において、Ｒ^３０およびＲ^３１はそれぞれ独立して炭素数１〜３のアルキルまたはフェニルであり、Ｒ^３２は炭素数１〜６のアルキレン、フェニレンまたはアルキル置換されたフェニレンであり、ｙは１〜１０の整数である。 When producing the polymer of component A, at least one siloxane-based diamine may be used in combination. Preferable examples of the siloxane-based diamine include diamine represented by the formula (15).

In the 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, y Is an integer from 1 to 10.

（式（１５−２）のポリマーの分子量は８５０〜３０００である。） Specific examples of the diamine represented by the formula (15) include the following compounds or polymers.

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

  When these siloxane-based diamines are used, the addition amount thereof is set to 0. 0 relative to the total amount of diamine used as a raw material when producing the A component and the B component for the purpose of exhibiting the above effects and preventing deterioration of other characteristics. 5-30 mol% is suitable and 1-10 mol% is more suitable.

  Among these diamines, aromatic (including heteroaromatic ring) diamines in which an amino group is directly bonded to an aromatic ring are particularly preferable from the viewpoint of giving good orientation to liquid crystals. Furthermore, the thing of the structure which does not contain oxygen and sulfur, such as an ester and an ether bond which tends to cause the electrical characteristic of a liquid crystal display element to fall is preferable. However, even if it has such a structure, there is no problem as long as the amount is within a range that does not adversely affect the electrical characteristics.

  The tetracarboxylic dianhydride that is a raw material for producing the polymer of component A can be selected from known compounds without limitation. Such tetracarboxylic dianhydrides include aromatic dicarboxylic anhydrides and heterocyclic aromatic rings in which two 2-oxapropane-1,3-dioyl groups (dicarboxylic anhydride groups) are directly bonded to the aromatic ring. They may belong to any group of dicarboxylic acid anhydrides, aliphatic dicarboxylic acid anhydrides in which the dicarboxylic acid anhydride group is not directly bonded to the aromatic ring, and heterocyclic aliphatic dicarboxylic acid anhydrides. The polyimide or polyamic acid preferably has a structure that does not contain oxygen or sulfur such as an ester or ether bond that tends to cause a decrease in the electrical characteristics of the liquid crystal display element. Therefore, the tetracarboxylic dianhydride preferably has a structure containing no oxygen or sulfur. However, even if it has such a structure, there is no problem as long as the amount is within a range that does not adversely affect the electrical characteristics.

Tetracarboxylic dianhydride is represented by Formula (20).

（Ｇ^３は単結合、炭素数１〜１２のアルキレン、１，４−フェニレン、または１，４−シクロヘキシレンであり、Ｘ^７は独立して単結合または−ＣＨ_２−である。）

（Ｒ^４１、Ｒ^４２、Ｒ^４３およびＲ^４４は独立して水素、メチル、エチルまたはフェニルである。）

（環Ｄ^１はシクロヘキサン環またはベンゼン環である。） Preferable examples of R ⁴⁰ in formula (20) are tetravalent groups represented by formula (21) to formula (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は単結合、−ＣＨ_２−、−ＣＨ_２ＣＨ_２−、−Ｏ−、−ＣＯ−、−Ｓ−、−Ｃ（ＣＨ_３）_２−、または−Ｃ（ＣＦ_３）_２−であり、環Ｄ^２は独立してシクロヘキサン環またはベンゼン環である。）

（Ｒ^４５は水素またはメチルである。）

（Ｘ^８は独立して単結合または−ＣＨ_２−であり、ｖは１または２である。）

^{(G 4} represents a single _{bond, -CH 2 -, - CH 2} CH 2 -, - O -, - CO -, - S -, - C (CH 3) 2 -, or -C _{(CF 3) 2} - with And 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は単結合または−ＣＨ_２−である。）

（Ｒ^４６は水素、メチル、エチルまたはフェニルであり、環Ｄ^３はシクロヘキサン環またはベンゼン環である。）

（ｗ１およびｗ２は独立して０または１である。）

(X ⁶ is a single bond or —CH ₂ —.)

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

(W1 and w2 are independently 0 or 1)

Specific examples of the tetracarboxylic dianhydride include compounds of the following formulas (A-1) to (A-43).

  In these tetracarboxylic dianhydrides, from the viewpoint of improving the photo-alignment ability of the liquid crystal alignment film, the formula (A-1), the formula (A-2), the formula (A-12), and the formula (A-14) , Formula (A-18), formula (A-20), formula (A-21), formula (A-28), formula (A-30), formula (A-37) or formula (A-40) It is preferable to use a compound, and it is particularly preferable to use a compound of formula (A-1), formula (A-12), formula (A-14), or formula (A-18). Further, from the viewpoint of improving VHR of the liquid crystal alignment film or reducing coloring, the formula (A-14), the formula (A-18), the formula (A-19), the formula (A-20), the 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 a compound of formula (A-43) is preferred, and a compound of formula (A-14), formula (A-18) or formula (A-21) is particularly preferred. The tetracarboxylic dianhydride is not limited to these, and other known compounds may be used as long as the object of the present invention is achieved. These tetracarboxylic dianhydrides may be used alone or in combination of two or more.

  As another constituent material used in the photoalignment agent of the present invention, it is important to select a polymer exhibiting liquid crystallinity or a B component which is a precursor thereof. The B component 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 alignment stability, it is preferable to use a liquid crystalline polymer having a liquid crystal phase at a relatively high temperature. From such a viewpoint, a component B having a liquid crystal temperature range in the range of 100 to 300 ° C., preferably 150 to 300 ° C. is used. When the alignment film of the present invention is produced, it is essential to use a heat treatment up to the liquid crystal temperature range in order to cause alignment amplification by the B component. As will be described later, when an alignment film is formed by using a polyamic acid as the A component and imidizing after photoalignment, it is preferable to imidize the A component within the liquid crystal temperature range of the B component.

  The type of the polymer of component B in the present invention is not particularly limited, and all known liquid crystal polymers can be used. However, the most suitable liquid crystalline polymer in terms of alignment stability includes polyamic acid that becomes polyimide when formed into a film, polyamic acid ester in which the carboxyl group of polyamic acid is esterified, or soluble polyimide. Of course, from a practical aspect, partially imidized polyamic acid can also be used. Specific examples of the liquid crystalline polyimide include a polyimide having a structural unit represented by the formula (VI) described in Macromol. Chem. Phys., 198, 519 (1997).

ここに、Ｒ^４は炭素数２〜２０のアルキレン、式（VIII）で表される２価の基、または式（IX）で表される２価の基であり、構成単位ごとに異なってもよく；そして、全構成単位数の６０％以上はＲ^４が炭素数６〜２０のアルキレンである構成単位である。Ｒ^４がアルキレンであるとき、このアルキレン中の１つまたは隣接しない２つの−ＣＨ_２−は−Ｏ−、−ＮＨ−、−Ｎ（ＣＨ_３）−、または−Ｓｉ（ＣＨ_３）_２ＯＳｉ（ＣＨ_３）_２−で置き換えられてもよい。

Here, R ⁴ is an alkylene having 2 to 20 carbon atoms, a divalent group represented by the formula (VIII), or a divalent group represented by the formula (IX). Well; and 60% or more of the total number of structural units is a structural unit in which R ⁴ is alkylene having 6 to 20 carbon atoms. When R ⁴ is alkylene, one or two non-adjacent —CH ₂ — in the alkylene is —O—, —NH—, —N (CH ₃ ) —, or —Si (CH ₃ ) ₂ OSi ( CH ₃ ) ₂ — may be substituted.

In order to exhibit the liquid crystallinity of the B component, for example, the structural unit in which R ⁴ in the formula (VI) is alkylene having 6 to 20 carbon atoms, that is, the structural unit having a flexible spacer is 6 to the entire structural unit. It is important that more than 10% exist. However, even if such a constitutional unit is a polymer of 60% or less, it can be selected as the B component if it can exhibit liquid crystallinity.

  In order to develop the liquid crystallinity of the B component, it is preferable to use, for example, an acid anhydride or a diamine having a skeleton having aromatic rings as shown in the formula (VI), that is, a long (flat) plane (core). . The ratio of the raw material having such a core is preferably selected from 50 to 100% by weight, and more preferably selected from 70 to 100% by weight based on the total amount of the raw material. However, even if the ratio of the raw material having such a core is 50% by weight or less, if the obtained polymer can exhibit liquid crystallinity, the polymer can be selected as the B component.

ここに、Ｘ^１およびＸ^２は独立して単結合、−Ｏ−、−ＣＯＯ−、−ＯＣＯ−、−ＮＨ−、−ＣＯＮＨ−、または炭素数１〜１２のアルキレンであり；Ｇ^１およびＧ^２は独立して単結合、または炭素数６〜１２の芳香族環および炭素数３〜１２の脂環式環から選ばれる１〜３個の環を含む２価の基であり；Ｒ^５は水素、フッ素、−ＣＮ、−ＯＨ、または炭素数１〜３０のアルキル、ペルフルオロアルキルもしくはアルコキシであり；そして、Ｘ^１、Ｇ^１、Ｘ^２およびＧ^２の全てが単結合である場合は、Ｒ^５は炭素数３〜３０のアルキル、ペルフルオロアルキルもしくはアルコキシであり、Ｇ^２が単結合でありＸ^２が単結合でもなくアルキレンでもない場合は、Ｒ^５は水素または炭素数３〜３０のアルキルであり、Ｇ^１およびＧ^２が共に単結合である場合は、Ｘ^１、Ｘ^２およびＲ^５の炭素数の合計が３以上である。 Other known acid anhydrides or diamines can be used as the raw material for the B component as long as the liquid crystallinity of the B component is not impaired. In this case, it is preferable to select a diamine represented by the following formula (VIII) or formula (IX) as another known raw material as a constituent component of R ^{4 from} the viewpoint of maintaining liquid crystallinity.

Wherein X ¹ and X ² are each independently a single bond, —O—, —COO—, —OCO—, —NH—, —CONH—, or alkylene having 1 to 12 carbons; G ¹ and G ² is independently a single bond or a divalent group containing 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, fluorine, —CN, —OH, or alkyl having 1 to 30 carbons, perfluoroalkyl or alkoxy; and when all of X ¹ , G ¹ , X ² and G ² are single bonds, R ⁵ is alkyl having 3 to 30 carbons, perfluoroalkyl or alkoxy, and when G ² is a single bond and X ² is neither a single bond nor alkylene, R ⁵ is hydrogen or alkyl having 3 to 30 carbons. Yes, ^{G 1} and ^{G 2} If both a single ^bond, the total number of carbon atoms of X 1, ^{X 2} and ^{R 5} is 3 or more.

ここに、Ｒ^５は水素または炭素数１〜１２のアルキルであり；環Ｂは任意の水素が炭素数１〜４のアルキルで置き換えられてもよい１，４−フェニレン、または任意の水素が炭素数１〜４のアルキルで置き換えられてもよい１，４−シクロへキシレンであり；Ｘ^０は単結合または炭素数１〜５のアルキレンであり；ｓは０〜３の整数であり；ｓが２であるとき、２つの環Ｂは同じであっても異なってもよく、２つのＸ^０も同じであっても異なってもよく；ｓが３であるとき、３つのまたは任意の２つの環Ｂは同じであっても異なってもよく、３つのまたは任意の２つのＸ^０も同じであっても異なってもよく；Ｚ^１およびＺ^２は独立して単結合、−ＣＨ_２−、−ＣＨ_２ＣＨ_２−または−Ｏ−であり；ｔ１およびｔ２は独立して０〜３の整数であり；ｔ１が２であるとき、２つのＺ^１は同じであっても異なってもよく；ｔ１が３であるとき、３つのまたは任意の２つのＺ^１は同じであっても異なってもよく；ｔ２が２であるとき、２つのＺ^２は同じであっても異なってもよく；ｔ２が３であるとき、３つのまたは任意の２つのＺ^２は同じであっても異なってもよい。

Wherein R ⁵ is hydrogen or alkyl having 1 to 12 carbons; ring B is 1,4-phenylene in which any hydrogen may be replaced by alkyl having 1 to 4 carbons, or any hydrogen is carbon 1,4-cyclohexylene which may be substituted with alkyl having 1 to 4; X ⁰ is a single bond or alkylene having 1 to 5 carbons; s is an integer of 0 to 3; When 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- and is; t1 and t2 are 0-3 independently When t1 is 2, the two Z ¹ may be the same or different; is a number when t1 is three, three, or any two of Z ¹ are different and can be the same When t2 is 2, 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 Good.

  When a structural unit having the structure of formula (VIII) or formula (IX) is selected, the abundance ratio of these structural units is 50% or less with respect to the total of the structural units. Is preferable for imparting.

（ここに、環Ｂ^１および環Ｂ^２は独立して単結合または１，４−シクロヘキシレンであり、Ｇ^３は単結合または−ＣＨ_２ＣＨ_２−であり、そしてＲ^７は水素または炭素数１〜２０のアルキルである。） When the liquid crystal alignment film of the present invention is used for IPS applications, selecting a structural unit containing only alkylene having 2 to 20 carbon atoms as R ⁴ described above can reduce the Pt angle of the liquid crystal and increase the orientation with respect to the azimuthal direction. It is preferable for improvement. On the other hand, when used for TN or VA applications, in order to control the Pt angle of the liquid crystal, R ⁴ preferably contains a structural unit having the structure of the above formula (VIII) or formula (IX). At this time, in order to maintain the liquid crystallinity of the B component, it is more preferable to select the structure of the 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 carbon number. 1-20 alkyl.)

  The blend ratio of the A component and the B component of the present invention is adjusted to the ratio of the B component to the total amount of the A component and the B component in accordance with the required values such as the photo-alignment property of the film, the stability of the alignment, and the coloring of the film. It can be arbitrarily selected between 5 and 95% by weight, and is preferably selected between 10 and 90% by weight. At this time, in order to improve the photo-alignment property and reduce the coloration of the film, it is preferable to select this ratio between 50 to 90% by weight. Moreover, in order to improve the stability of orientation, it is preferable to select this ratio between 30 to 80% by weight.

  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 organosilicon compounds are aminopropyltrimethoxysilane, aminopropyltriethoxysilane, vinyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl)- 3-aminopropyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxy A silane coupling agent such as (cyclohexyl) ethyltrimethoxysilane, and a silicone oil such as dimethylpolysiloxane, polydimethylsiloxane, and polydiphenylsiloxane.

  The addition ratio of the organosilicon compound to the alignment agent is not particularly limited as long as the effect of the present invention is obtained. However, when a large amount of the organosilicon compound is added, liquid crystal alignment failure may occur when the alignment film is formed. Therefore, when the organosilicon compound is added, the concentration thereof is preferably in the range of 0.01 to 5% by weight, particularly preferably 0.1 to 3% by weight, based on the weight of the polymer contained in the aligning agent. Range.

  The aligning agent of the present invention further contains a compound having two or more functional groups that react with the carboxylic acid residue of the polyamic acid or its derivative, so-called cross-linking agent, from the viewpoint of preventing deterioration of characteristics over time and deterioration due to the environment. May be. Examples of such a crosslinking agent include polyfunctional epoxies and isocyanate materials as described in Japanese Patent No. 3049699, Japanese Patent Application Laid-Open No. 2005-275360, Japanese Patent Application Laid-Open No. 10-212484, and the like.

  A crosslinking agent that reacts with the crosslinking agent itself to form a polymer having a network structure and improves the film strength of polyamic acid or polyimide can be used for the same purpose as described above. Examples of such a crosslinking agent include polyfunctional vinyl ethers, maleimides, and bisallyl nadiimide derivatives as described in JP-A-10-310608, JP-A-2004-341030, and the like. When these crosslinking agents are used, the preferred ratio is 5 to 100% by weight, more preferably 10 to 50% by weight, based on the total amount of the polymer components.

  The aligning agent of the present invention contains a solvent having the ability to dissolve polyamic acid or a derivative thereof. Such solvents widely include solvents usually used in the production and use of polyamic acid or derivatives thereof, and can be appropriately selected according to the purpose of use. Examples of these solvents are 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- Examples include lactones such as dimethylacetamide, dimethylsulfoxide, N, N-dimethylformamide (DMF), N, N-diethylformamide, N, N-diethylacetamide (DMAc), and γ-butyrolactone (GBL).

  Examples of other solvents other than the above-mentioned solvents for the purpose of improving coatability include alkyl lactate, 3-methyl-3-methoxybutanol, tetralin, isophorone, ethylene glycol monobutyl ether (BCS), etc. Ethylene glycol monoalkyl ether, diethylene glycol monoalkyl ether such as diethylene glycol monoethyl ether, ethylene glycol monoalkyl and phenyl acetate, triethylene glycol monoalkyl ether, propylene glycol monoalkyl ether such as propylene glycol monobutyl ether, diethyl malonate, etc. Dipropylene glycol monoalkyl ethers such as dialkyl malonate and dipropylene glycol monomethyl ether, and these glycol monoethers Ester compounds such as Le acids and the like. Among these, NMP, dimethylimidazolidinone, GBL, BCS, diethylene glycol monoethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether and the like can be particularly preferably used as the solvent.

  The alignment agent of the present invention may further contain various additives as desired. For example, when a further improvement in coatability is desired, a surfactant suitable for such purpose may be contained, and when a further improvement in antistatic property is required, an appropriate amount of an antistatic agent may be contained.

  The concentration of the polyamic acid or derivative thereof in the alignment agent of the present invention is not particularly limited, but is preferably 0.1 to 40% by weight. When this aligning agent is applied to the substrate, an operation of diluting the contained polyamic acid with a solvent in advance may be required to adjust the film thickness.

  In order to develop better properties as an alignment film, the alignment agent in the present invention may be mixed with one or more kinds selected from all other known polymers. At this time, the sum of the A component and the B component in the entire polymer is preferably 50% by weight or more, and more preferably 80% by weight or more in order to express the effect of the present invention.

  The solid content concentration in the alignment agent of the present invention is not particularly limited, and an optimum value may be selected according to the following various coating methods. Usually, in order to suppress unevenness and pinholes at the time of application, the content is preferably 0.1 to 30% by weight, more preferably 1 to 10% by weight, based on the varnish weight.

  As described above, the alignment film of the present invention contains the above-described A component, B component, the other components described above that are added as necessary, and a solvent that dissolves these, and an alignment agent (varnish). Can be obtained. This aligning agent is applied to the substrate by the method described below, and the solvent is removed by heating (pre-baking) at a relatively low temperature as necessary. Furthermore, in order to further accelerate imidization or solvent removal of polyimide, polyamic acid, or polyamic acid derivative, and to exhibit the original properties of the alignment film, heating (main firing) is performed at a relatively high temperature. The film thus obtained can be obtained by irradiating light to orient the polymer.

At this time, from the viewpoint of expressing sufficient orientation, the alignment film of the present invention is preferably produced by the following procedure using polyamic acid as the component A.
(1) The varnish is applied onto a substrate by a brush coating method, a dipping method, a spinner method, a spray method, a printing method, or the like.
(2) The film formed on the substrate is heated at 50 to 120 ° C., preferably 80 to 100 ° C., to evaporate the solvent.
(3) The film is irradiated with light to orient the polyamic acid in the film.
(4) The film in which the polyamic acid is oriented is heated at 150 to 300 ° C., preferably 180 to 250 ° C., and imidized.

  In addition, when a predetermined pretilt angle is to be expressed in a liquid crystal display element using an alignment film, a method of irradiating a substrate with linearly polarized light from an arbitrary angle when irradiating light, or a straight line from a direction perpendicular to the substrate. It can be performed by combining polarized light irradiation and non-polarized light irradiation from an arbitrary angle.

  In the production of the alignment film of the present invention, linearly polarized light is used for the alignment of the polyamic acid. The polyamic acid main chain is oriented in a direction perpendicular to the polarization direction of the linearly polarized light by irradiation with the linearly polarized light. The linearly polarized light is not particularly limited as long as it is light capable of orienting the polyamic acid in the film. The alignment film of the present invention can be aligned by low energy light irradiation. Therefore, the irradiation amount of linearly polarized light in the photo-alignment treatment of the polyamic acid is preferably 0.5 to 10 J / cm 2. The wavelength of linearly polarized light is preferably 300 to 400 nm. Although the irradiation angle with respect to the film surface of linearly polarized light is not particularly limited, it is preferable from the viewpoint of shortening the alignment processing time that it is as perpendicular as possible to the film surface in order to develop a strong alignment regulating force for the liquid crystal.

  In the production of the alignment film of the present invention, the light applied to the film when it is desired to express the pretilt angle may be polarized light or non-polarized light. When it is desired to develop a pretilt angle, the amount of light applied to the film is preferably 0.5 to 10 J / cm2, and the wavelength is preferably 300 to 400 nm. When it is desired to express the pretilt angle, the irradiation angle of the light irradiated to the film with respect to the film surface is not particularly limited, but is preferably 30 to 60 degrees from the viewpoint of shortening the alignment processing time.

  The alignment film of the present invention is particularly characterized by having a large orientation anisotropy. The magnitude of such anisotropy can be evaluated by a method using polarized IR described in JP-A-2005-275364. Further, as shown in the following examples, evaluation can also be made by a method using ellipsometry. When the alignment film of the present invention is used as an alignment film for a liquid crystal composition, a material having a larger film anisotropy is considered to have a large alignment regulating force for the liquid crystal composition.

  The alignment film of the present invention can be used for alignment control of an optical compensation material and all other liquid crystal materials in addition to the alignment use of a liquid crystal composition for a liquid crystal display. Further, since the alignment film of the present invention has large anisotropy, it can be used alone for an optical compensator application.

  The present invention is formed on a pair of substrates disposed opposite to each other, an electrode formed on one or both of the surfaces opposed to each of the pair of substrates, and a surface opposed to each of the pair of substrates. A liquid crystal display element having a liquid crystal alignment film formed and a liquid crystal layer formed between the pair of substrates, wherein the liquid crystal alignment film is the 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. Examples of such electrodes include ITO and metal vapor deposition films. Further, 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. Examples of the desired shape of the electrode include a comb shape or a zigzag structure. The electrode may be formed on one of the pair of substrates, or may be formed on both substrates. The form of electrode formation varies depending on the type of liquid crystal display element. For example, in the case of an IPS liquid crystal display element, an electrode is disposed on one of the pair of substrates, and in the case of other liquid crystal display elements, the electrodes of the pair of substrates are arranged. Electrodes are arranged on both sides. The liquid crystal alignment film is formed on the substrate or electrode.

  The liquid crystal layer is formed in such a manner that the liquid crystal composition is sandwiched between the pair of substrates facing each other on which the liquid crystal alignment film is formed. In the formation of the liquid crystal layer, a spacer such as fine particles or a resin sheet that is interposed between the pair of substrates to form an appropriate interval can be used as necessary. The liquid crystal composition is not particularly limited, and a known liquid crystal composition can be used.

  The alignment film of the present invention can improve the characteristics of all known liquid crystal compositions when a liquid crystal display element is formed as a liquid crystal alignment film. In particular, it is highly effective in improving alignment defects of large screen displays that are difficult to rub. Such a large screen display is driven and controlled by TFTs. Liquid crystal compositions used for such TFT type liquid crystal display elements are described in Japanese Patent No. 3086228, Japanese Patent No. 2635435, Japanese Patent Laid-Open No. 5-501735, and Japanese Patent Laid-Open No. 9-255556. Yes. Therefore, the alignment film of the present invention is preferably used in combination with the liquid crystal composition described therein.

  The pretilt angle in the liquid crystal display element of the present invention is described in, for example, Journal of Applied Physics, Vol. 48, No. 5, p.1783-1792 (1977) using a liquid crystal characteristic evaluation apparatus OMS-CA3 manufactured by Chuo Seiki. It can be measured by the crystal rotation method.

  The liquid crystal display element of the present invention is excellent in electrical characteristics relating to the reliability of the liquid crystal display element. Such electrical characteristics include voltage holding ratio and ion density.

  The voltage holding ratio (VHR) is a ratio at which the voltage applied to the liquid crystal display element during the frame period is held in the liquid crystal display element, and indicates display characteristics of the liquid crystal display element. The liquid crystal display element of the present invention uses a rectangular wave of 5 V and a frequency of 30 Hz, has a voltage holding ratio measured at a temperature of 60 ° C. of 90.0% or more, and uses a rectangular wave of 5 V and a frequency of 0.3 Hz. From the viewpoint of preventing display defects, it is preferable that the voltage holding ratio measured at a temperature of 60 ° C. is 85.0% or more.

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

  The liquid crystal display element of the present invention preferably has an ion density of 500 pC or less from the viewpoint of preventing image sticking of the liquid crystal display element.

  EXAMPLES 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 used by distilling commercially available products. Compound (I-1), Compound (II-1), and Compound (A-21) are Tetrahedron, Vol. 60, 9977 (2004), Japanese Patent Publication No. 5-65530, and Japanese Patent Laid-Open No. 58-109479, respectively. Was synthesized according to The following compound TPDA and compound (30) were synthesized according to Macromolecules, Vol. 28, 6368 (1995) and JP-A No. 2004-341030. Compound (X-1) was recrystallized from ethanol and used for the experiment. Compound (3-5-1) was synthesized by the same method as described in JP-A No. 2002-162630. The polymer was prepared in a nitrogen stream.

  For the light irradiation, a 250 W high-pressure mercury lamp manufactured by Seiei Inai was used, and ultraviolet rays having a wavelength of about 310 to 380 nm were irradiated. Irradiation was performed in air at room temperature.

The evaluation method of the liquid crystal display element used in the examples is shown below.
<Measurement of alignment film retardation, film thickness, and pretilt angle>
It was determined using a spectroscopic ellipsometer M-2000U (manufactured by JAWoollam Co. Inc.). In this example, the retardation value of the film increases in proportion to the degree of orientation of the polymer main chain. That is, those having a large retardation value have a large degree of orientation.
<Measurement of UV-Vis spectrum>
Using a UV-Vis spectrum measuring device (JASCO V-660), a glass substrate on which no alignment film was formed was measured as a reference.
<Voltage holding ratio>
It carried out by the method as described in "Mizushima et al., The 14th Liquid Crystal Discussion Meeting Proceedings, p. The measurement was performed by applying a rectangular wave having a wave height of ± 5 V to the cell. The measurement was performed at 60 ° C. This value is an index indicating how much the applied voltage is retained after the frame period. If this value is 100%, it indicates that all charges are retained.
<Measurement of ion content in liquid crystal (ion density)>
According to the method described in Applied Physics, Vol. 65, No. 10, 1065 (1996), measurement was performed using a liquid crystal property measuring system 6254 type manufactured by Toyo Technica. Using a triangular wave with a frequency of 0.01 Hz, measurement was performed at a voltage range of ± 10 V and a temperature of 60 ° C. If the ion density is high, defects such as seizure due to ionic impurities are likely to occur. That is, the ion density is a physical property value that is an index for predicting the occurrence of image sticking.
<Weight average molecular weight (Mw)>
The weight average molecular weight (Mw) of the polyamic acid in the liquid crystal aligning agent was determined by using gel permeation chromatography (GPC, manufactured by Shodex, GF7MHQ), and using 0.6% by weight phosphoric acid-containing DMF as an eluent. The column temperature was 50 ° C. and polystyrene was used as a standard solution.
<Phase transition point of polymer liquid crystal>
The thin film (thickness: about 70 nm) formed on the substrate was baked at 230 ° C. for 10 minutes, and then observed and determined with a polarizing microscope. Separately, the polymer liquid crystal obtained by reprecipitation was measured with a differential scanning calorimeter. However, since the thin film state and the phase transition temperature were different, the measurement by the previous method was adopted.
<Viscosity>
It measured at 25 degreeC using the viscometer (the Toki Sangyo company make, TV-22).
<Glass transition temperature>
Measurement was performed using a differential scanning calorimeter (DSC, manufactured by Perkin Elmer, Diamond DSC).

[Synthesis Example 1]
<Preparation of polyamic acid varnish A>
4,4′-Diaminotolane (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. The viscosity of this product was 350 mPa · s. This solution was stirred at 60 ° C. for about 4 hours to obtain 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 the glass transition temperature (Tg) exceeded 300 ° C.

[Synthesis Examples 2 to 7]
<Preparation of polyamic acid varnishes B to G>
Polyamic acid varnishes B to G were prepared by the same method as in Synthesis Example 1 with the raw material compositions shown in Table 1, and the physical properties were measured in the same manner as in Synthesis Example 1. The parentheses indicate mol%.

<Table 1>

[Synthesis Example 8]
<Preparation of polyamic acid varnish I>
1,8-Diaminooctane (DAO) (0.7009 g, 4.858 mmol) was dissolved in NMP (22.5 g), and TPDA (1.7791 g, 4.858 mmol) was added at room temperature. After stirring at 60 ° C. for 2 hours, the mixture was cooled to room temperature, BC (22.5 g) was added, and varnish H was obtained. The viscosity of this varnish was 18.7 mPa · s. (Weight average molecular weight; 18,000). The phase transition point (nematic-isotropic phase) was 235 ° C.

[Synthesis Example 9]
<Preparation 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). The phase transition point (nematic-isotropic phase) was 212 ° C.

[Synthesis Example 10]
<Preparation of soluble polyimide varnish K>
DAO (0.7009 g, 4.858 mmol) was dissolved in NMP (22.5 g) and TPDA (1.7791 g, 4.858 mmol) was added at room temperature. After stirring at 60 ° C. for 2 hours, the mixture 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. The obtained precipitate was washed twice with 100 ml of pure water and then vacuum-dried at 100 ° C. for 8 hours. This polymer (1.0 g) was dissolved in NMP (10 g), and BC (10 g) was added to obtain Varnish J. The viscosity of this varnish was 9.8 mPa · s. (Weight average molecular weight; 16,000). The phase transition point (nematic-isotropic phase) was 231 ° C.

[Synthesis Examples 11 to 16]
<Preparation of polyamic acid varnishes K to P>
Polyamic acid varnishes K to P were prepared in the same manner as in Synthesis Example 8 with the raw material compositions shown in Table 2. The parentheses indicate mol%.

表２において、ＤＡＤは１、１２−ジアミノドデカンを意味する。
<Table 2>

In Table 2, DAD means 1,12-diaminododecane.

[Example 1]
0.50 g of varnish A and varnish H was weighed into a sample bottle, and NMP / BC = 1/1 (% by weight) was added to make 1.67 g. The polyamic acid solution of about 3% by weight was dropped on a transparent glass substrate and applied by a spinner method (2,000 rpm, 15 seconds). After coating, the substrate was heated at 80 ° C. for 3 minutes to evaporate the solvent, and then irradiated with linearly polarized light through a polarizing plate (at 365 nm, energy of about 4 J / cm 2). The substrate after light irradiation was heat-treated in an oven at 230 ° C. for 10 minutes to obtain an alignment film A having a thickness of about 70 nm. When the retardation of this alignment film A was measured, it was 2.0 nm.

Ｆ^１）：配向膜Ｅを得るのに用いたものと同じポリマー成分に対し、重量比０．２０の化合物（３０）をさらに加えた。
Ｊ^２）：配向膜Ｉと同じポリマー条件で、焼成条件を２００℃、１０分に変えた。 [Examples 2 to 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 measuring 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 used to obtain the alignment film E.
J2 ⁾ : The baking conditions were changed to 200 ° C. and 10 minutes under the same polymer conditions as those of the alignment film I.

[Comparative Example 1]
Instead of the mixture of varnish B and varnish H, varnish B was used alone, and an alignment film O was obtained in the same manner as in Example 1, and the retardation thereof was measured. The result was 0.6 nm.

[Comparative Example 2]
Instead of a mixture of varnish B and varnish H, varnish E was used, and an alignment film P was obtained in the same manner as in Example 1, and the retardation thereof 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, and an alignment film Q was obtained in the same manner as in Example 1, and the retardation thereof was measured. The result was 1.3 nm.

[Example 15]
The UV-Vis spectrum of the alignment film B produced in Example 2 was measured. The results are shown in FIG.

[Comparative Example 4]
The UV-Vis spectrum of the alignment film O produced in Comparative Example 1 was measured. The results are shown in FIG. 1 together with the data of the alignment film B.

  When comparing the Examples and Comparative Examples 1 to 3, the alignment film of the present invention obtained by combining the A component and the B component has a larger retardation value than the alignment film obtained only from the A component, that is, the retardation value is It can be seen that it is important to add a liquid crystalline polymer to the photo-alignment agent in order to increase it. Further, it can be seen from FIG. 1 that the alignment film B has a higher transmittance at 380 to 500 nm than the alignment film O and is less colored.

[Example 16]
An alignment with a film thickness of about 60 nm is performed in the same manner as in Example 1 except that the glass substrate is replaced with a transparent glass substrate provided with an ITO electrode on one side and the combination of varnishes is the same as in the alignment films B, E and F. Membranes B ′, E ′ and F ′ were obtained. The two substrates on which the alignment films are formed on the ITO electrode are opposed to each other so that the polarization directions of the linearly polarized light irradiated to the respective alignment films are parallel to each other, and the surfaces on which the alignment films are formed are opposed to each other. Further, a gap for injecting the liquid crystal composition was formed between the facing alignment films and bonded together to assemble liquid crystal cells B, E and F (liquid crystal display elements) having a cell thickness of 7 μm. Then, a liquid crystal composition A shown below was injected into these cells.

<Liquid crystal composition A>

  When the liquid crystal cells B, E, and F were visually observed, none of the so-called flow alignment in which the liquid crystals were aligned along the direction in which the liquid crystals flowed was observed. These liquid crystal cells B, E and F were subjected to isotropic treatment at 110 ° C. for 30 minutes and cooled to room temperature. And when these liquid crystal cells B, E, and F were observed with a microscope, no alignment defect of liquid crystal was observed. When the polarizing microscope was set to the crossed Nicols state and the liquid crystal cells B, E and F were rotated, clear bright and dark states were observed. Table 4 below shows the pretilt angles, VHR (voltage holding ratio), and ion density of these liquid crystal cells B, E, and F.

このように、本発明の配向膜を液晶表示素子用の配向膜に応用した場合、実用に耐えうる十分な特性を有していることが分かる。 <Table 4>

Thus, it can be seen that when the alignment film of the present invention is applied to an alignment film for a liquid crystal display element, it has sufficient characteristics to withstand practical use.

[Example 17]
1.60 g each of varnishes G and K was weighed into a sample bottle, and NMP / BC = 1/1 (% by weight) was added to make 4.00 g. The mixed varnish having a polyamic acid concentration of about 4% by weight was dropped 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 coating, the substrate was heated at 80 ° C. for 3 minutes to evaporate the solvent, and then the substrate plane was tilted 45 degrees with respect to the light source and irradiated with non-polarized light (energy of about 5 J / cm ^{2 at} 365 nm). The substrate after light irradiation was heat-treated at 230 ° C. for 30 minutes to obtain an alignment film R having a thickness of about 60 nm.
Two substrates having the alignment film formed on the ITO electrode are opposed to each other on the surface on which the alignment film is formed, and a gap for injecting the liquid crystal composition is formed between the facing alignment films. In addition, a liquid crystal cell R having a cell thickness of 4 μm was assembled. The substrates were laminated in the same direction with the left and right sides reversed, where the inclined direction was left and right, and the direction perpendicular to the inclined direction was up and down. Then, a 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. When the liquid crystal cell R was observed with a polarizing microscope, the dark state did not change even when the liquid crystal cell R was rotated in the crossed Nicol state, and no light leakage due to alignment defects of the liquid crystal was observed. The pretilt angle of the liquid crystal cell R was measured by the above method and found to be 89.1 degrees. The direction in which the liquid crystal is tilted is the direction of irradiation with non-polarized light. When a voltage (5 V) was applied to the liquid crystal cell R and observed with a polarizing microscope, no schlieren structure due to alignment defects was observed in the entire region of the cell, and a clean alignment was obtained. Further, when the liquid crystal cell R was rotated in this state, clear brightness and darkness were observed. The liquid crystal cell R had a VHR (voltage holding ratio) of 97.9% at 30 Hz, 91.7% at 0.3 Hz, and an ion density of 460 pC.

<Liquid crystal composition B>

[Example 18]
A liquid crystal cell S was produced 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. When the liquid crystal cell S was observed with a polarizing microscope, the dark state did not change even when the liquid crystal cell S was rotated in the crossed Nicol state, and no light leakage due to alignment defects in the liquid crystal was observed. The pretilt angle of the liquid crystal cell S was measured by the above method and found to be 89.1 degrees. When a voltage (5 V) was applied to the liquid crystal cell S and observed with a polarizing microscope, no schlieren structure due to alignment defects was observed in the entire region of the cell, and a clean alignment was obtained. The liquid crystal cell S had a VHR (voltage holding ratio) of 95.6% at 30 Hz, 88.7% at 0.3 Hz, and an ion density of 820 pC.

  The liquid crystal cell S was irradiated with light from a fluorescent lamp (8 watts) placed at a distance of 10 cm for 72 hours at an irradiation angle of 45 degrees to perform a light resistance test. The pretilt angle after light irradiation was measured and found to be 89.1 degrees.

Further, half of the liquid crystal cell S was covered with aluminum foil, and a light resistance test was performed in the same manner as described above. When a voltage (3.2 V) was applied to the liquid crystal cell S after light irradiation and the display part was observed under crossed Nicols, no change was observed between the light irradiated part and the light non-irradiated part (FIG. 2). .

[Examples 19 to 23]
Liquid crystal cells T to X were obtained in the same manner as in Example 18 using the varnish shown in Table 5. Table 5 shows the results of vertical alignment, pretilt angle, display at the time of voltage application, VHR, ion density, and light resistance test of the liquid crystal cells T to X.

<Table 5>

[Comparative Example 5]
A 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. When the liquid crystal cell Y was observed with a polarizing microscope, the dark state did not change even when the liquid crystal cell Y was rotated in the crossed Nicol state, and no light leakage due to alignment defects in the liquid crystal was observed. The pretilt angle of the liquid crystal cell Y was measured by the above method and found to be 89.1 degrees. When a voltage (5 V) was applied to the liquid crystal cell Y and observed with a polarizing microscope, no schlieren structure due to alignment defects was observed in the entire cell area, and a clean alignment was obtained. The pretilt angle of the liquid crystal cell Y was measured and found to be 89.0 degrees.

  The light resistance test of the liquid crystal cell Y was performed in the same manner as in Example 18. As a result of measuring the pretilt angle after light irradiation, it was 89.6 degrees. Moreover, when the light irradiation part and the non-irradiation part were observed, a clear difference was observed between the light irradiation part and the light non-irradiation part (FIG. 3).

[Comparative Example 6]
A liquid crystal cell Z was produced 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). When the liquid crystal cell Z was observed with a polarizing microscope, the dark state did not change even when the liquid crystal cell Z was rotated in the crossed Nicol state, and no light leakage due to alignment defects in the liquid crystal was observed. When the pretilt angle of the liquid crystal cell Z was measured, it was 89.9 degrees. Further, when a voltage (5 V) was applied to the liquid crystal cell Z and observed with a polarizing microscope, alignment defects were observed in several places in the entire area of the cell.

Claims (11)

A photo-alignment agent containing at least one polymer having photo-alignment ability as an A component and containing at least one polymer having a liquid crystal temperature range in the range of 100 to 300 ° C. as a B component : It is at least one selected from the group consisting of polyamic acid, partially imidized polyamic acid and polyimide . The photo-alignment agent according to claim 1, wherein the component A is a polymer having a photosensitive group in its main chain. A component is a polymer having at least one photosensitive group represented by formulas (I) to (V) and (X) in its main chain, and B component is a polyamic acid, a partially imidized polyamic acid, and At least one liquid crystalline polymer selected from the group consisting of polyimides, wherein the polymer is one or two non-adjacent to the main chain —CH ₂ — is —O—, —NH—, —N (CH ₃ ) -, or _{-Si (CH 3) 2 OSi (} CH 3) 2 - in which a polymer having a straight-chain alkylene structure which may C6-20 replaced, photoalignment agent according to claim 1:

Here, R ¹ , R ² and R ³ are independently aromatic divalent groups. The component A is represented by formulas (I-1) to (I-3), formula (II-1) to formula (II-3), formula (III-1), formula (IV-1) to formula (IV-3). ), A photo-alignment according to claim 3 , which is a polymer obtained by using at least one of compounds represented by formula (V-1) and formula (X-1) to formula (X-8) as a raw material. Agent.

The photo-alignment agent according to claim 3 , wherein the B component is a polyimide having a structural unit represented by the formula (VI) or a polyamic acid of a precursor thereof.

Here, R ⁴ is one or two non-adjacent —CH ₂ — being —O—, —NH—, —N (CH ₃ ) —, or —Si (CH ₃ ) ₂ OSi (CH ₃ ) ₂ —. An alkylene having 2 to 20 carbon atoms that may be substituted, a divalent group represented by the formula (VIII), or a divalent group represented by the formula (IX), and may be different for each structural unit And 60% or more of the total number of structural units is one in which R ⁴ is one or two non-adjacent —CH ₂ — is —O—, —NH—, —N (CH ₃ ) —, or —Si (CH ₃ ); ₂ is a structural unit of alkylene having 6 to 20 carbon atoms which may be replaced by OSi (CH ₃ ) ₂ —.

(Where 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 A single bond or a divalent group containing 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, fluorine,- CN, —OH, or alkyl having 1 to 30 carbons, perfluoroalkyl or alkoxy; and when all of X ¹ , G ¹ , X ² and G ² are a single bond, R ⁵ is carbon 3 R ⁵ is hydrogen or alkyl of 3 to 30 carbons when G ² is a single bond and X ² is neither a single bond nor an alkylene, and G ¹ and G ² are both a single bond If ^it, the total number of carbon atoms in X 1, ^{X 2} and ^{R 5} is 3 or more.)

(Wherein R ⁶ is hydrogen or alkyl having 1 to 12 carbons; ring B is 1,4-phenylene in which any hydrogen may be replaced by alkyl having 1 to 4 carbons, or any hydrogen is 1,4-cyclohexylene which may be substituted with alkyl having 1 to 4 carbon atoms, X ⁰ is a single bond or alkylene having 1 to 5 carbon atoms, and 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 a -O-, 0 to 3 of t1 and t2 are independently When t1 is 2, the two Z ¹ may be different and are the same; is a number when t1 is three, three, or any two of Z ¹ may be different and the same When t2 is 2, the two Z ² may be the same or different; when t2 is 3, the three or any two Z ² may be the same or different.) The component A is represented by formulas (I-1) to (I-3), formula (II-1) to formula (II-3), formula (III-1), formula (IV-1) to formula (IV-3). ), Formula (V-1), and a polymer obtained by using at least one of the compounds represented by formula (X-1) to formula (X-8) as a raw material, the component B is represented by formula (VI) The photo-alignment agent of Claim 3 which is the polyamic acid of the polyimide which has the structural unit represented by this, or its precursor.

Here, R ⁴ is one or two non-adjacent —CH ₂ — being —O—, —NH—, —N (CH ₃ ) —, or —Si (CH ₃ ) ₂ OSi (CH ₃ ) ₂ —. An alkylene having 2 to 20 carbon atoms that may be substituted, a divalent group represented by the formula (VIII), or a divalent group represented by the formula (IX), and may be different for each structural unit And 60% or more of the total number of structural units is one in which R ⁴ is one or two non-adjacent —CH ₂ — is —O—, —NH—, —N (CH ₃ ) —, or —Si (CH ₃ ); ₂ is a structural unit of alkylene having 6 to 20 carbon atoms which may be replaced by OSi (CH ₃ ) ₂ —.

(Wherein X ¹ and X ² are each independently a single bond, —O—, —COO—, —OCO—, —NH—, —CONH—, or alkylene having 1 to 12 carbons; G ¹ and G ² is independently a single bond or a divalent group containing 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, fluorine, —CN, —OH, or alkyl having 1 to 30 carbons, perfluoroalkyl or alkoxy; and when all of X ¹ , G ¹ , X ² and G ² are single bonds, R ⁵ is alkyl, perfluoroalkyl or alkoxy having 3 to 30 carbon atoms, and when G ² is a single bond and X ² is neither a single bond nor alkylene, R ⁵ is hydrogen or alkyl having 3 to 30 carbon atoms. in it, ^{G 1} and G If is both a single ^bond, X 1, ^{X 2} and the total number of carbon atoms of ^{R 5} is 3 or more.)

(Wherein R ⁶ is hydrogen or alkyl having 1 to 12 carbons; ring B is 1,4-phenylene in which any hydrogen may be replaced by alkyl having 1 to 4 carbons, or any hydrogen is 1,4-cyclohexylene which may be replaced by alkyl having 1 to 4 carbon atoms; X ⁰ is a single bond or alkylene having 1 to 5 carbon atoms; s is an integer of 0 to 3; When is 2, the two rings B may be the same or different, and the two X ⁰ may be the same or different; when s is 3, three or any two Ring 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- and is; t1 and t2 are independently 0-3 When t1 is 2, the two Z ¹ may be the same or different; an integer when t1 is 3, three or any two of Z ¹ are different and can be the same When t2 is 2, 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 Good.) R ⁴ in the formula (VI) is an alkylene having 2 to 20 carbon atoms or a divalent group represented by the formula (VIII-1), and may be different depending on the number of structural units; The photo-alignment agent according to claim 6 , wherein 60% or more is a structural unit in which R ⁴ is alkylene having 6 to 20 carbon atoms.

(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 carbon number. 1-20 alkyl.) The photo-alignment agent according to any one of claims 1 to 7 , wherein a ratio of the A component based on the total weight of the A component and the B component is 10 to 90% by weight. The liquid crystal aligning film manufactured using the photoalignment agent of any one of Claims 1-8 . The liquid crystal display element manufactured using the liquid crystal aligning film of Claim 9 . The heat processing which heats up to the liquid crystal temperature of B component, after apply | coating the photo-alignment agent of any one of Claims 1-7 to a board | substrate, and forming into a film and irradiating light and aligning the film | membrane A method for producing a liquid crystal alignment film, comprising:

Images