JP4666137B2 - Method for forming liquid crystal alignment film, liquid crystal display element and optical member - Google Patents

Description

The present invention is a method of forming a liquid crystal alignment film, a liquid crystal display device and the optical member. More particularly, without rubbing, a method of forming a liquid crystal alignment film capable of imparting the liquid crystal alignment capability by irradiation of radiation that is polarized, the liquid crystal display element and the optical member having a liquid crystal alignment film such as this About.

Conventionally, a nematic liquid crystal having positive dielectric anisotropy is sandwiched with a substrate with a transparent electrode having a liquid crystal alignment film, and the major axis of liquid crystal molecules is continuously twisted between 0 and 360 degrees between the substrates as necessary. There are known liquid crystal display elements having a liquid crystal cell of a TN (Twisted Nematic) type, a STN (Super Twisted Nematic) type, an IPS (In Plane Switching) type, and the like. (See Patent Documents 1 and 2).
As a means for aligning the liquid crystal in such a liquid crystal cell, an organic film is formed on the substrate surface, and then the surface of the organic film is rubbed in one direction with a cloth material such as rayon to provide liquid crystal alignment ability (rubbing). And a method of forming a monomolecular film having a long-chain alkyl group using a Langmuir-Blodgett method (LB method). Of these, rubbing is generally used from the viewpoint of substrate size, liquid crystal alignment uniformity, processing time, and processing cost.

However, if the alignment of the liquid crystal is performed by rubbing, dust is likely to be generated in the process or static electricity is likely to be generated, so that dust adheres to the alignment film surface and causes display defects. there were. In particular, in the case of a substrate having a TFT (Thin Film Transistor) element, there has been a problem that the circuit damage of the TFT element occurs due to the generated static electricity, resulting in a decrease in yield. Further, in liquid crystal display elements that will be further refined in the future, unevenness occurs on the surface of the substrate as the density of pixels increases, so that uniform rubbing is a problem.
As another means of aligning the liquid crystal in the liquid crystal cell, the liquid crystal is irradiated by irradiating polarized or non-polarized radiation to a photosensitive thin film such as polyvinyl cinnamate or poly (4′-methacryloyloxychalcone) formed on the substrate surface. A photo-alignment technique that imparts alignment ability is known. According to this method, uniform liquid crystal alignment can be realized without generating static electricity or dust (see Patent Documents 3 to 11).

Conventionally, in the display, optoelectronics, and optical fields, optical members such as polarizing plates, phase difference plates, and optically rotatory optical films have been used. These optical members have various uses. For example, in addition to being widely used as a member such as a polarizing plate, a compensation plate, and a viewing angle improving film in a liquid crystal display device, they are also used as a phase difference plate for an optical pickup element in an optical disk device. It has been.
As a method for producing such an optical member, many methods such as a method using a stretched and oriented resin film have been conventionally known. However, the optical member manufactured by such a method has the same optical characteristics over the entire surface, and it has not been possible to obtain an optical member having different optical characteristics in different regions within the surface.

  On the other hand, the prior invention (see Patent Documents 12 to 13) reveals a method of fixing an alignment state after aligning a liquid crystal substance having an optical function on a liquid crystal alignment film formed on a substrate by a photo-alignment technique. I have to. By this method, an optical member having different optical characteristics in different regions within the surface can be easily manufactured.

As described above, the liquid crystal alignment film manufactured by the optical alignment technique can be effectively applied to a liquid crystal display element and an optical member. However, the conventional photo-alignment technique using a photo-crosslinkable material such as polyvinyl cinnamate has a problem that a large amount of radiation is necessary to obtain a stable liquid crystal alignment ability. That is, in such a liquid crystal alignment film, since the anisotropy of the liquid crystal alignment film is maintained by the cross-linked structure caused by radiation irradiation, the liquid crystal alignment ability is unstable when the radiation irradiation amount is not sufficiently large. become.
JP 56-91277 A JP-A-1-120528 JP-A-6-287453 JP-A-10-251646 JP-A-11-2815 JP 11-152475 A JP 2000-144136 A JP 2000-319510 A JP 2000-281724 A JP 2003-307736 A JP 2004-163646 A JP-A-6-289374 JP 2004-20658 A

The objective of this invention is providing the formation method of the liquid crystal aligning film which can provide liquid crystal aligning ability by irradiation of a polarized or non-polarized radiation, without performing a rubbing process.
Another object of the present invention is to provide a method for forming a liquid crystal alignment film that requires a small amount of radiation for imparting stable liquid crystal alignment ability.
Still another object of the present invention is to provide a liquid crystal alignment film.
Still another object of the present invention is to provide a liquid crystal display device.
Still another object of the present invention is to provide an optical member.
Still other objects and advantages of the present invention will become apparent from the following description.

According to the present invention, the above objects and advantages of the present invention are:
On the board
[A] a polymer having a structure capable of undergoing a crosslinking reaction by radiation;
[B] a polymerizable compound having an ethylenically unsaturated bond, and
[C] radiation sensitive polymerization initiator,
To form a coating film of be that the liquid crystal aligning agent containing,
It is achieved by a method for forming a liquid crystal alignment film, comprising a step of irradiating the coating film with linearly polarized light or partially polarized radiation .

Further, according to the present invention, the above objects and advantages of the present invention are achieved by a liquid crystal alignment film formed by the method for forming a liquid crystal alignment film of the present invention.
Furthermore, according to the present invention, the above objects and advantages of the present invention are achieved by a liquid crystal display element having the liquid crystal alignment film of the present invention.
Furthermore, according to the present invention, the above objects and advantages of the present invention are achieved by an optical member using the liquid crystal alignment film of the present invention.

When Ru good method for forming a liquid crystal alignment film of the present invention, as compared with the case of the conventional photo-alignment method, a small radiation dose, it is possible to obtain a high stability of the liquid crystal alignment capability liquid crystal alignment film. Therefore, when this liquid crystal alignment film is applied to a liquid crystal display element, a liquid crystal display element having excellent display characteristics can be manufactured at a lower cost than before. In addition, when the above liquid crystal alignment film is applied to the production of an optical member, an optical member having excellent in-plane uniformity can be produced at a lower cost than before. Therefore, these liquid crystal display elements and optical members can be effectively applied to various devices, and are suitably used for display devices such as desk calculators, watches, table clocks, counting display boards, word processors, personal computers or liquid crystal televisions. .

Liquid crystal alignment agent in the liquid crystal aligning agent present invention, a polymer having a structure capable of crosslinking reaction by [A] radiation polymerizable compound having a [B] ethylenically unsaturated bond, and, [C] radiation-sensitive polymerization initiator It contains an agent. [A] The radiation-crosslinkable polymer is one that undergoes a cross-linking reaction selectively when the liquid crystal alignment film is irradiated with polarized or non-polarized radiation and exhibits liquid crystal alignment ability. On the other hand, the [B] polymerizable compound and the [C] polymerization initiator cause a polymerization reaction in the radiation irradiation step to form a strong polymer matrix. In the liquid crystal alignment film of the present invention, since the structure of the liquid crystal alignment film is stabilized by the polymer matrix, the stability of the liquid crystal alignment ability is increased even with a small radiation dose.

The total amount of the [B] polymerizable compound and the [C] polymerization initiator contained in the liquid crystal aligning agent in the present invention is 0.1 to 50 parts by weight with respect to 100 parts by weight of the [A] radiation crosslinkable polymer. Preferably, it is 0.5 to 20 parts by weight, more preferably 1 to 10 parts by weight. When the total amount of the [B] polymerizable compound and the [C] polymerization initiator contained in the liquid crystal aligning agent in the present invention is less than the above range, the structure stabilizing effect of the alignment film cannot be sufficiently obtained, When the total amount is larger than the above range, the ratio of the [A] radiation crosslinkable polymer in the alignment intermediate film is lowered, resulting in a decrease in the liquid crystal alignment ability of the alignment film obtained. . In the liquid crystal aligning agent of the present invention, the ratio of [B] The polymerizable compound used [C] The polymerization initiator to [B] the polymerizable compound 100 parts by weight, [C] a polymerization initiator 1 The amount is preferably 100 parts by weight, and more preferably 10 to 50 parts by weight.

[A] Radiation-crosslinkable polymer [A] The radiation-crosslinkable polymer contained in the liquid crystal aligning agent in the present invention is a polymer that has a structure in the side chain or main chain that is sensitive to radiation and can be crosslinked. As such a structure sensitive to radiation, a conjugated enone structure represented by the following formulas (I) to (III);

P ¹ —CH═CH—CO—Q ¹ − (I)

^{-P 2 -CH = CH-CO-} Q 2 ····· (II)

^{-P 3 -CH = CH-CO-} Q 3 - ····· (III)

Here, Q ¹ , P ² , P ³ and Q ³ are divalent organic groups having an aromatic ring, and P ¹ and Q ² are monovalent organic groups having an aromatic ring.

And a flavonoid structure obtained by removing one or two hydrogen atoms from the structure represented by the following formula (IV);

ここで、Ｑ^４は芳香環を有する１価の有機基であり、Ａ^４およびＢ^４は互いに独立に、水素原子、水酸基、ハロゲン原子、シアノ基または炭素数１〜６の１価の有機基であり、ｂは０〜４の整数である、ただし、複数あるＢ^４は互いに同一でも異なっていてもよい。
を挙げることができる。

Here, Q ⁴ is a monovalent organic group having an aromatic ring, and A ⁴ and B ⁴ are independently of each other a hydrogen atom, a hydroxyl group, a halogen atom, a cyano group, or a monovalent organic group having 1 to 6 carbon atoms. And b is an integer of 0 to 4, provided that a plurality of B ⁴ may be the same as or different from each other.
Can be mentioned.

In the above formulas (I) to (IV), Q ¹ , P ² , P ³ and Q ³ are divalent organic groups having an aromatic ring, and P ¹ , Q ² and Q ⁴ are monovalent organic groups having an aromatic ring. Organic group. P ¹ , P ² , P ³ , Q ¹ , Q ² , Q ³ and Q ⁴ are preferably an organic group having 6 to 20 carbon atoms which may be substituted with a halogen atom, such as a hydrocarbon group. Specific examples of the monovalent organic group (P ¹ , Q ² , Q ⁴ ) having an aromatic ring include a phenyl group, a 4-methoxyphenyl group, a 4-pentylphenyl group, a 4-octylphenyl group, 4- Fluorophenyl group, 3-methoxyphenyl group, 3-pentylphenyl group, 3-octylphenyl group, 3-fluorophenyl group, 3,4-difluorophenyl group, 3,4,5-trifluorophenyl group, 4-triphenyl Fluoromethylphenyl group, 3-trifluoromethylphenyl group, biphenyl group, 4-pentylbiphenyl group, 4-octylbiphenyl group, 4-fluorobiphenyl group, 3,4-difluorobiphenyl group, 3,4,5-trifluoro Biphenyl group, 1-naphthyl group, 4-octyl-1-naphthyl group, 5-pentyl-1-naphthyl group, 2-naphthyl group, 6 Octyl-2-naphthyl group, 9-anthracenyl group, 9-anthracenyl group, and a 10-pentyl-9-anthracenyl group. Specific examples of the divalent organic group (Q ¹ , P ² , P ³ , Q ³ ) having an aromatic ring include a 1,2-phenylene group, a 3-fluoro-1,2-phenylene group, 4-fluoro-1,2-phenylene group, 3-methoxy-1,2-phenylene group, 4-methoxy-1,2-phenylene group, 3-methyl-1,2-phenylene group, 4-methyl-1, 2-phenylene group, 1,3-phenylene group, 2-fluoro-1,3-phenylene group, 4-fluoro-1,3-phenylene group, 5-fluoro-1,3-phenylene group, 2-methoxy-1 , 3-phenylene group, 4-methoxy-1,3-phenylene group, 5-methoxy-1,3-phenylene group, 2-methyl-1,3-phenylene group, 4-methyl-1,3-phenylene group, 5-methyl-1,3-phenylene group, 1,4 Phenylene group, 2-fluoro-1,4-phenylene group, 2-methoxy-1,4-phenylene group, 2-methyl-1,4-phenylene group, 4,4′-biphenylene group, 3,4′-biphenylene Group, 3,3′-biphenylene group and the like.

The monovalent organic group in A ⁴ and B ⁴ in the above formula (IV) includes methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec- C1-C6 alkyl groups such as butyl, t-butyl, n-pentyl, and n-hexyl; methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, t An alkoxyl group having 1 to 6 carbon atoms such as butoxy group, n-pentyloxy group, n-hexyloxy group; trifluoromethyl group, 2,2,2-trifluoroethyl group, 1,1,2,2 , A halogenated alkyl group having 1 to 6 carbon atoms such as 2-pentafluoroethyl group; trifluoromethoxy group, 2,2,2-trifluoroethoxy group, 1,1,2,2,2-pentafluoroethoxy group Carbon like Halogenated alkoxyl group having 1 to 6 are mentioned as preferred. Each of A ⁴ and B ⁴ is particularly preferably a hydrogen atom, a fluorine atom, a methyl group, a methoxy group, a trifluoromethyl group or the like, and more preferably a hydrogen atom.

Furthermore, when the liquid crystal aligning agent in the present invention is applied to a liquid crystal display element having a liquid crystal cell such as a TN (Twisted Nematic) type, STN (Super Twisted Nematic) type, or VA (Vertical Alignment) type, the liquid crystal aligning agent. Is selected from the group consisting of an alkyl group having 10 to 30 carbon atoms, an alicyclic skeleton-containing group having 10 to 30 carbon atoms, and a fluorine-containing organic group having 2 or more carbon atoms. It is preferable to impart vertical orientation or pretilt angle expression by introducing at least one hydrophobic group. The “pretilt angle” in the present invention represents an angle of inclination of liquid crystal molecules from a direction parallel to the substrate surface. On the other hand, when the liquid crystal aligning agent of the present invention is applied to a liquid crystal display element having a liquid crystal cell such as an IPS (In Plane Switching) type or an optical member such as a retardation plate, a pretilt angle is expressed. In general, it is not preferable, and therefore it is preferable to use a polymer that does not contain a hydrophobic group as described above.

  When the hydrophobic group is introduced into the side chain of the polymer, the ratio of the repeating unit having the hydrophobic group to the entire repeating unit of the polymer is preferably 3 to 50 when used in the vertical alignment mode. %, More preferably 5 to 30%, particularly preferably 10 to 15%. Moreover, when using for modes other than vertical alignment, although a preferable content rate changes with target pretilt angles, it is preferable to make the upper limit into 30%.

  Examples of the hydrophobic group having 10 to 30 carbon atoms include an n-decyl group, an n-dodecyl group, an n-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, an n-octadecyl group, and an n-eicosyl group. And a linear alkyl group such as a group. Examples of the alicyclic skeleton-containing group having 10 to 30 carbon atoms include a cholesteryl group and a cholestanyl group. Examples of the fluorine-containing organic group having 2 or more carbon atoms include 1,1,1-trifluoroethyl group, pentafluoroethyl group, 4-fluorocyclohexyl group, pentafluorocyclohexyl group, 4-fluorophenyl group, penta Examples include a fluorophenyl group and a group represented by the following formula (VI). The alkyl group, alicyclic skeleton-containing group and fluorine-containing organic group are, for example, linking groups such as —O—, —CO—, —COO—, —OCO—, —NHCO—, —CONH— or —S—. It may be bonded to the polymer via

ここで式中、Ａ^１は−Ｏ−、−ＣＯ−、−ＣＯＯ−、−ＯＣＯ−、−ＮＨＣＯ−、−ＣＯＮＨ−または−Ｓ−で表される２価の結合基であり、Ａ^２はフッ素原子またはトリフルオロメチル基である。

Here, A ¹ is a divalent linking group represented by —O—, —CO—, —COO—, —OCO—, —NHCO—, —CONH— or —S—, and A ² is A fluorine atom or a trifluoromethyl group;

  Among these, an alkyl group having 10 to 30 carbon atoms and an alicyclic skeleton-containing group having 10 to 30 carbon atoms are preferable, and a linear alkyl group having 15 to 20 carbon atoms, a cholesteryl group, and a cholestanyl group are more preferable. An n-hexadecyl group and an n-octadecyl group are particularly preferable.

  [A] The main chain skeleton of the radiation crosslinkable polymer is not particularly limited, and specifically, (1) polyimide, (2) polyester, (3) polyamide, (4) poly (meth) acrylate, ( Examples include 5) polystyrene, (6) styrene-phenylmaleimide copolymer, (7) polyamic acid, (8) polyamic acid ester, (9) polysiloxane, and (10) polyvinyl acetal. Of these, (1) polyimide, (4) poly (meth) acrylate, (5) polystyrene, (6) styrene-phenylmaleimide copolymer, (7) polyamic acid or (8) polyamic acid ester are particularly preferred. (5) Polystyrene, (6) styrene-phenylmaleimide copolymer or (8) polyamic acid ester are more preferred, and (8) polyamic acid ester is more preferred.

  Examples of the radiation crosslinkable polymer having the (8) polyamic acid ester skeleton include a polymer represented by the following formula (V).

ここで、Ｓ^５は２価の有機基であり、Ｔ^５は４価の有機基であり、Ｚ^１およびＺ^２は互いに独立に水酸基または１価の有機基であり、Ｚ^１およびＺ^２のうち少なくとも１つは、前記式（Ｉ）〜（III）のそれぞれで表わされる共役エノン構造または前記式（Ｖ）で表わされる化合物から１つまたは２つの水素原子を除去して得られるフラボノイド構造を有する１価の有機基である。

Here, S ⁵ is a divalent organic group, T ⁵ is a tetravalent organic group, Z ¹ and Z ² are each independently a hydroxyl group or a monovalent organic group, and Z ¹ and Z ² At least one of them has a conjugated enone structure represented by each of the formulas (I) to (III) or a flavonoid structure obtained by removing one or two hydrogen atoms from the compound represented by the formula (V). It is a monovalent organic group.

  Specific examples of such a polymer include the polymer described in Patent Document 10 and the polyamic acid ester described in Patent Document 11, and the polymer described in Patent Document 10 is preferable. More preferable examples include a polymer having at least one structure selected from structures represented by the following formulas (i) to (iii).

  Examples of the radiation crosslinkable polymer having the (5) polystyrene or (6) styrene-phenylmaleimide copolymer skeleton include a polymer having a repeating unit represented by the following formula (VII).

ここで、Ｓ^７は水素原子または１価の有機基であり、ｒは０以上１以下の実数であり、Ｚ^３およびＺ^４は互いに独立に水素原子、水酸基または１価の有機基であり、Ｚ^３およびＺ^４のうち少なくとも１つは、前記式（Ｉ）〜（ＩＩＩ）のそれぞれで表わされる共役エノン構造または前記式（Ｖ）で表わされる化合物から１つまたは２つの水素原子を除去して得られるフラボノイド構造を有する１価の有機基である。

Here, S ⁷ is a hydrogen atom or a monovalent organic group, r is a real number of 0 or more and 1 or less, Z ³ and Z ⁴ are each independently a hydrogen atom, a hydroxyl group or a monovalent organic group, At least one of Z ³ and Z ⁴ removes one or two hydrogen atoms from the conjugated enone structure represented by each of the formulas (I) to (III) or the compound represented by the formula (V). It is a monovalent organic group having a flavonoid structure.

  Specific examples of the radiation crosslinkable polymer represented by the above formula (VII) include the polymer described in Patent Document 9 and the polystyrene derivative and poly (styrene-phenylmaleimide) derivative described in Patent Document 11. The polymer described in Patent Document 9 can be exemplified as a preferable one, and more preferably has at least one structure selected from the structures represented by the following formulas (iv) to (v). A polymer can be mentioned.

  Specific examples of the radiation-crosslinkable polymer having the (4) poly (meth) acrylate skeleton include poly (meth) acrylates described in Patent Documents 4, 6 and 7. . Among these, poly (meth) acrylates described in Patent Documents 6 and 7 are preferable, and a polymer having at least one structure selected from structures represented by the following formulas (vi) to (viii) is more preferable.

[B] Polymerizable Compound As the polymerizable compound [B] used in the present invention, a monofunctional, bifunctional, or trifunctional or higher (meth) acrylate is preferably used from the viewpoint of good polymerizability.

  Examples of the monofunctional (meth) acrylate include 2-hydroxyethyl (meth) acrylate, carbitol (meth) acrylate, isobornyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, and 2- (meth) acryloyloxyethyl. And 2-hydroxypropyl phthalate. As the commercial item, for example, Aronix M-101, M-111, M-114 (manufactured by Toa Gosei Chemical Co., Ltd.), KAYARAD TC-110S, TC-120S (manufactured by Nippon Kayaku Co., Ltd.) , Biscote 158, 2311 (manufactured by Osaka Organic Chemical Industry Co., Ltd.).

  Examples of the bifunctional (meth) acrylate include ethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, and polypropylene glycol di (meth) acrylate. , Tetraethylene glycol di (meth) acrylate, bisphenoxyethanol full orange acrylate, and the like. As the commercial products, for example, Aronix M-210, M-240, M-6200 (manufactured by Toa Gosei Chemical Co., Ltd.), KAYARAD HDDA, HX-220, R-604 (Nippon Kayaku Co., Ltd.) ), Viscoat 260, 312 and 335HP (Osaka Organic Chemical Co., Ltd.).

Examples of the trifunctional or higher functional (meth) acrylate include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, tri ((meth) acryloyloxyethyl) phosphate, and pentaerythritol tetra (meth) acrylate. , Dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like. As the commercial product, for example, Aronix M-309, M-400, M-402, M-405, M-450, M-7100, M-8030, M-8060 (Toa Gosei Chemical) Industrial Co., Ltd.), KAYARAD TMPTA, DPHA, DPCA-20, DPCA-30, DPCA-60, DPCA-60, DPCA-120 (manufactured by Nippon Kayaku Co., Ltd.), Biscote 295, 300, 360 , GPT, 3PA, and 400 (manufactured by Osaka Organic Chemical Industry Co., Ltd.).
Among these, bifunctional or trifunctional or higher (meth) acrylate is preferable to monofunctional (meth) acrylate, and trifunctional or higher (meth) acrylate is particularly preferable. These monofunctional, bifunctional, or trifunctional or higher (meth) acrylates are used alone or in combination.

[C] Radiation sensitive polymerization initiator Examples of the [C] polymerization initiator used in the present invention include a radiation sensitive radical polymerization initiator and a radiation sensitive cationic polymerization initiator.
When using these polymerization initiators, it is necessary to consider whether the irradiation condition is an oxygen atmosphere or an oxygen-free atmosphere. When radiation irradiation is performed in an oxygen-free atmosphere, all general types of radiation-sensitive radical polymerization initiators and radiation-sensitive cationic polymerization initiators can be used. On the other hand, when irradiation is performed in an oxygen atmosphere, depending on the type of radiation-sensitive radical polymerization initiator, radicals are deactivated by oxygen and the sensitivity is lowered, and the structure stabilization effect of the alignment film cannot be sufficiently obtained. There is a case. However, the radiation-sensitive cationic polymerization initiator hardly deactivates the active species due to oxygen, and can be freely used regardless of whether it is in an oxygen atmosphere or an oxygen-free atmosphere.

  Examples of radiation-sensitive radical polymerization initiators include α-diketones such as benzyl and diacetyl; acyloins such as benzoin; acyloin ethers such as benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether; thioxanthone, 2,4- Benzophenones such as diethylthioxanthone, thioxanthone-4-sulfonic acid, benzophenone, 4,4′-bis (dimethylamino) benzophenone, 4,4′-bis (diethylamino) benzophenone; acetophenone, p-dimethylaminoacetophenone, α, α '-Dimethoxyacetoxybenzophenone, 2,2'-dimethoxy-2-phenylacetophenone, p-methoxyacetophenone, 2-methyl-1- [4- (methylthio) phenyl] -2-mol Acetophenones such as olinopropane-1-one and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one; quinones such as anthraquinone and 1,4-naphthoquinone; phenacyl chloride , Halogen compounds such as tribromomethylphenylsulfone, tris (trichloromethyl) -s-triazine; acylphosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide; and peroxidations such as di-t-butyl peroxide Things.

Examples of commercially available radiation-sensitive radical polymerization initiators include IRGACURE-184, 369, 500, 651, 907, 1700, 819, 1000, 2959, 149, 1800, 1850. , Darocur-1173, 1116, 2959, 1664, 4043 (manufactured by Ciba Specialty Chemicals), KAYACURE-DETX, MBP, DMBI, EPA, OA (manufactured by Nippon Kayaku Co., Ltd.) , VICU-10, 55 (STAFFFER Co. LTD), TRIGONALP1 (AKZO Co. LTD), SANDORAY 1000 (SANDOZ Co. LTD), DEAP (APJOHN Co. LTD, QUANTACURE-PDO) Same EP (Manufactured by WARD BLEKINSOP Co.LTD), and the like.
Among these, preferable examples include acetophenones such as 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one.

  Furthermore, examples of the radiation-sensitive cationic polymerization initiator include phenyldiazonium tetrafluoroborate, phenyldiazonium hexafluorophosphonate, phenyldiazonium hexafluoroarsenate, phenyldiazonium trifluoromethanesulfonate, phenyldiazonium trifluoroacetate, phenyldiazonium-p-toluene. And sulfonate salts; and (1-6-η-cumene) (η-cyclopentadienyl) iron (1+) hexafluorophosphate (1-) metallocene compounds.

  Commercially available products of this radiation-sensitive cationic polymerization initiator include, for example, ADEKA ULTRASET PP-33 which is a diazonium salt, OPTOMER SP-150 and 170 which are sulfonium salts (Asahi Denka Kogyo). And Irgacure 261 (manufactured by Ciba Specialty Chemicals), which is a metallocene compound.

  In addition, by using these radiation-sensitive radical polymerization initiator or radiation-sensitive cationic polymerization initiator and a radiation-sensitive sensitizer together, a liquid crystal aligning agent that is a highly sensitive radiation-sensitive resin composition that is less deactivated by oxygen. It is also possible to obtain.

Solvent The liquid crystal aligning agent in this invention contains the said [A] radiation crosslinkable polymer, [B] polymeric compound, and [C] polymerization initiator. The solvent used at this time is not particularly limited as long as it is an organic solvent capable of dissolving the above components. Examples of such solvents include non-protons such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea and hexamethylphosphortriamide. Examples include polar solvents; phenolic solvents such as m-cresol, xylenol, phenol and halogenated phenol; halogenated solvents such as chlorobenzene, dichloroethane and tetrachloroethane; ketone solvents such as cyclohexanone. These solvents can be used alone or in combination of two or more. In addition, the poor solvent of the polymer used for the said solvent can be used together in the range in which a polymer does not precipitate.

Other Additives The liquid crystal aligning agent used in the present invention can also contain various thermosetting crosslinking agents in order to stabilize the pretilt angle and increase the coating film strength. A polyfunctional epoxy-containing compound is effective as the thermosetting cross-linking agent. Bisphenol A type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, cyclic aliphatic epoxy resin, glycidyl ester type epoxy resin, glycidyl diamine type Epoxy resins, heterocyclic epoxy resins, epoxy group-containing acrylic resins, and the like can be used. Examples of commercially available products include Epolite 400E, 3002 (manufactured by Kyoeisha Yushi Chemical Co., Ltd.), Epicoat 828, 152, and epoxy novolac 180S (manufactured by Yuka Shell Epoxy Co., Ltd.).

  Furthermore, when using the aforementioned polyfunctional epoxy-containing compound, a basic catalyst such as 1-benzyl-2-methylimidazole can be added for the purpose of efficiently causing a crosslinking reaction.

The liquid crystal aligning agent in the present invention can also contain a radiation curable crosslinking agent in order to further enhance the stability of the liquid crystal aligning ability. As such a crosslinking agent, specifically, the following formula (VIII)

^{P 8 -CH = CH-CO-} Q 8 (VIII)

Here, P ⁸ and Q ⁸ are the same or different and are monovalent organic groups having an aromatic ring.
The compound represented by these can be mentioned.

Here, as the monovalent organic group having an aromatic ring represented by P ⁸ and Q ⁸ , specifically, a phenyl group, a 4-methoxyphenyl group, a 4-pentylphenyl group, a 4-octylphenyl group, 4-fluorophenyl group, 3-methoxyphenyl group, 3-pentylphenyl group, 3-octylphenyl group, 3-fluorophenyl group, 3,4-difluorophenyl group, 3,4,5-trifluorophenyl group, 4 -Trifluoromethylphenyl group, 3-trifluoromethylphenyl group, biphenyl group, 4-pentylbiphenyl group, 4-octylbiphenyl group, 4-fluorobiphenyl group, 3,4-difluorobiphenyl group, 3,4,5- Trifluorobiphenyl group, 1-naphthyl group, 4-octyl-1-naphthyl group, 5-pentyl-1-naphthyl group, 2-naphthyl group Group, 6-octyl-2-naphthyl group, 9-anthracenyl group, 9-anthracenyl group, and a 10-pentyl-9-anthracenyl group.

Moreover, the liquid crystal aligning agent in this invention can contain a functional silane containing compound in order to improve adhesiveness with a board | substrate. Examples of the functional silane-containing compound include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, and N- (2-aminoethyl). -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-amino Propyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxyylsilyl-1 4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N- bis (oxyethylene) -3-aminopropyltrimethoxysilane and N- bis (oxyethylene) -3-aminopropyltriethoxysilane, and JP 63 - tetracarboxylic dianhydride and an amino group of 291,922 JP The reaction material with a containing silane compound can be mentioned.

Liquid crystal alignment film Examples of the method for forming the liquid crystal alignment film of the present invention include the following methods. First, the liquid crystal aligning agent in the present invention is applied to the transparent conductive film side of the substrate provided with the transparent conductive film by a roll coater method, a spinner method or a printing method, and heated at a temperature of 40 to 200 ° C. Form. The film thickness of the coating film is preferably 0.001 to 1 μm, more preferably 0.005 to 0.5 μm as a solid content (dry coating film). As the substrate, for example, a transparent substrate made of glass or a plastic film such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, or polycarbonate can be used. As the transparent conductive film, an indium oxide-based film or a tin oxide-based film can be used. Photolithographic methods, printing methods, and the like can be applied to patterning these transparent conductive films. In applying the liquid crystal aligning agent, a functional silane-containing compound or titanate may be applied in advance on the substrate and the transparent conductive film in order to further improve the adhesion between the substrate and the transparent conductive film and the coating film. it can.

  Subsequently, the coating film is irradiated with linearly polarized light, partially polarized radiation or non-polarized radiation, and in some cases, a heat treatment is further performed at a temperature of 150 to 250 ° C. to impart liquid crystal alignment ability. As the radiation, ultraviolet rays and visible rays having a wavelength of 150 nm to 800 nm can be used. Ultraviolet light having a wavelength of 320 nm to 450 nm is preferred. When the radiation to be used is linearly polarized light or partially polarized light, the irradiation may be performed from a direction perpendicular to the substrate surface, or may be performed from an oblique direction in order to give a pretilt angle. You may go. When irradiating non-polarized radiation, the direction of irradiation needs to be oblique to the substrate surface. Moreover, in order to improve liquid crystal aligning ability, you may irradiate, heating a board | substrate to 50-250 degreeC.

  In addition, upon irradiation with radiation, for the purpose of preparing liquid crystal alignment films having different orientation directions in different regions within the plane, radiation having different polarization state, optical axis direction, and energy is applied to each region within the surface. Can be irradiated. As a method of changing the polarization state of the irradiated radiation, the direction of the optical axis, and the energy in-plane, the method of performing irradiation through a photomask, while changing the light intensity, the incident angle, etc. as necessary, Examples thereof include a method of sweeping the coating film with light. These methods can be used alone or in combination. Further, one or both of these methods may be combined with the batch irradiation on the entire surface of the substrate. A particularly preferable method is to give the first orientation to a part of the substrate by irradiation through a photomask, and then give the second orientation to the remainder by exposing the entire surface of the substrate.

  As the light source, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, or an excimer laser can be used. The ultraviolet rays in the preferable wavelength region can be obtained by means of using a filter or a diffraction grating in combination with the light source. For example, it can be obtained by using, together with the light source, a material that does not transmit ultraviolet light having a wavelength shorter than 320 nm, such as a Pyrex glass polarizing plate.

Liquid crystal display element The liquid crystal display element of this invention is manufactured as follows, for example. First, the two substrates on which the liquid crystal alignment film is formed are opposed to each other so that the polarization direction of the linearly polarized radiation previously irradiated becomes a predetermined angle and bonded together with a sealant, and then the liquid crystal is injected, and the injection hole is formed. The liquid crystal cell is assembled by sealing. At this time, it is desirable to remove the flow alignment at the time of liquid crystal injection by heating the cell to a temperature at which the liquid crystal takes an isotropic phase and then cooling it to room temperature. Next, a polarizing plate is attached to both surfaces of the cell so that the polarizing direction of the polarizing plate forms a predetermined angle with the polarizing direction of the linearly polarized radiation, thereby obtaining a liquid crystal display element. When the liquid crystal alignment film is horizontally oriented, the TN type, STN type, or IPS type can be arbitrarily adjusted by adjusting the angle formed by the polarization direction of the linearly polarized radiation to be irradiated and the angle between each substrate and the polarizing plate. A liquid crystal display element such as can be obtained. On the other hand, when the liquid crystal alignment film is vertically aligned, the cell is configured so that the directions of easy alignment axes of the two substrates on which the liquid crystal alignment film is formed are parallel, and a polarizing plate is attached to the polarizing plate. A liquid crystal display element having a vertical alignment type liquid crystal cell can be obtained by bonding so that the direction forms an angle of 45 degrees with the easy alignment axis.

  As the sealing agent, for example, an epoxy resin containing a curing agent and aluminum oxide spheres as a spacer can be used.

  As the liquid crystal, nematic liquid crystal, smectic liquid crystal, or the like can be used. In the case of a TN type liquid crystal cell, STN type liquid crystal cell and IPS type liquid crystal cell, those composed of liquid crystal molecules having positive dielectric anisotropy to form a nematic type liquid crystal are preferable. For example, a Schiff base type liquid crystal, an azoxy type liquid crystal, Biphenyl liquid crystal, phenyl cyclohexane liquid crystal, ester liquid crystal, terphenyl liquid crystal, biphenyl cyclohexane liquid crystal, pyrimidine liquid crystal, dioxane liquid crystal, bicyclooctane liquid crystal, or cubane liquid crystal are used. Further, for example, a cholesteric liquid crystal such as cholesteryl chloride, cholesteryl nonate, and cholesteryl carbonate, a chiral agent such as that sold under the trade name C-15 or CB-15 (manufactured by Merck & Co., Inc.), and the like are used. You can also Furthermore, a ferroelectric liquid crystal such as p-decyloxybenzylidene-p-amino-2-methylbutylcinnamate can also be used. In the case of a vertically aligned liquid crystal cell, a liquid crystal molecule having negative dielectric anisotropy that forms a nematic liquid crystal is preferable. For example, a dicyanobenzene liquid crystal, a pyridazine liquid crystal, a Schiff base liquid crystal, an azoxy liquid crystal is preferable. Type liquid crystal, biphenyl type liquid crystal, or phenylcyclohexane type liquid crystal is used.

  As a polarizing plate used outside the liquid crystal cell, for example, a polarizing plate formed by sandwiching a polarizing film called an H film that absorbs iodine while stretching and aligning polyvinyl alcohol with a cellulose acetate protective film, or a polarizing film composed of the H film itself A board etc. can be mentioned.

Optical Member The optical member of the present invention can be manufactured by various methods described in Patent Document 13, for example. Among them, a particularly preferable method is a method in which a polymerizable liquid crystal material is aligned on the liquid crystal alignment film of the present invention and then solidified by polymerizing the material by irradiation with radiation.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Synthesis example 1
Polymerization of polyamic acid 0.1 mol (22.4 g) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride and 0.1 mol (10.8 g) of p-phenylenediamine were added to 300 g of N-methyl-2-pyrrolidone. It was dissolved and reacted at 60 ° C. for 6 hours. The reaction mixture was then poured into a large excess of methanol to precipitate the reaction product. Then, it wash | cleaned with methanol and it was made to dry at 40 degreeC under pressure reduction for 15 hours, and 27.4 g of polyamic acids (henceforth "the polymer O") were obtained.

[A] Synthesis of photosensitive polymer 16.6 g of polymer O was charged with 350 g of N-methyl-2-pyrrolidone, 38.7 g of 1-bromo-6- (4-chalconyloxy) hexane and 13.8 g of potassium carbonate. The mixture was added and reacted at 120 ° C. for 4 hours. The reaction mixture was then poured into water to precipitate the reaction product. The obtained precipitate was washed with water and dried under reduced pressure for 15 hours to obtain 35.4 g of a polyamic acid ester (hereinafter referred to as “[polymer A1”).

Comparative Synthesis Example 1
Imidization reaction To 20.0 g of the polymer O, 380 g of N-methyl-2-pyrrolidone, 9.5 g of pyridine and 12.3 g of acetic anhydride were added, and an imidization reaction was performed at 120 ° C. for 4 hours. The reaction mixture was then poured into a large excess of methanol to precipitate the reaction product. Thereafter, it was washed with methanol and dried under reduced pressure for 15 hours to obtain 15.3 g of polyimide (hereinafter referred to as “polymer Aa”).

Reference example 1
The polymer Aa obtained in Comparative Synthesis Example 1 was dissolved in γ-butyrolactone to obtain a solution having a solid content concentration of 2.5% by weight, and this solution was filtered through a filter having a pore size of 1 μm to obtain a liquid crystal aligning agent (hereinafter, “ Liquid crystal aligning agent P ") was prepared. This solution was applied onto the transparent electrode surface of the glass substrate with a transparent electrode made of an ITO film using a spinner so that the film thickness became 0.1 μm, and dried at 180 ° C. for 1 hour to form a thin film. The thin film was rubbed at a rotational speed of 500 rpm and a stage moving speed of 1 cm / sec using a rubbing machine having a roll around which a nylon cloth was wound. Next, for the pair of substrates subjected to the rubbing treatment, an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm is screen-printed on the surface on which the liquid crystal alignment film is formed, and then the rubbing directions are orthogonal to each other. The adhesive was heat-cured at 150 ° C. over 1 hour. Next, a nematic liquid crystal (ZLI-1565 manufactured by Merck & Co., Inc.) was filled between the pair of substrates from the liquid crystal injection port, and then the liquid crystal injection port was sealed with an epoxy adhesive. Furthermore, in order to remove the flow alignment at the time of liquid crystal injection, after heating this at 150 ° C. and then slowly cooling it to room temperature, the polarizing direction of the polarizing plate coincides with the rubbing direction of the liquid crystal alignment film of each substrate. Further, when the liquid crystal display element was produced by pasting it on both outer sides of the substrate, the orientation of the liquid crystal was good. When a voltage of 5 V was applied, a change in brightness of the liquid crystal display element was observed in response to ON / OFF of the applied voltage.

Reference example 2
In the same manner as in Reference Example 1, the liquid crystal aligning agent P was applied onto a glass substrate using a spinner so that the film thickness was 0.1 μm, and dried at 180 ° C. for 1 hour to form a thin film. The thin film was rubbed at a rotational speed of 500 rpm and a stage moving speed of 1 cm / sec using a rubbing machine having a roll around which a nylon cloth was wound.
50 parts by weight of 4 (4-n-butylcyclohexyl) cyclohexyl acrylate, 50 parts by weight of 4 (4-n-propylcyclohexyl) phenyl acrylate, photopolymerization initiator IRGACURE907 (manufactured by Ciba Specialty Chemicals) (2-methyl-1) 1 part by weight of-[4- (methylthio) phenyl] -2-morpholinopropan-1-one) and 100 parts by weight of propylene glycol monomethyl ether acetate as a solvent were mixed to prepare a polymerizable liquid crystal.
This polymerizable liquid crystal was applied and aligned on the rubbing-treated alignment film using a spinner. Next, in order to polymerize and solidify the applied polymerizable liquid crystal, ultraviolet rays were irradiated for 1 minute at 100 mW / cm ² using a high-pressure mercury lamp in a nitrogen atmosphere. The solvent in the polymerizable liquid crystal was volatilized and removed by raising the temperature by ultraviolet irradiation.
In this way, a retardation plate having a retardation at a wavelength of 633 nm of 317 nm was obtained. This retardation plate was colorless and transparent, and had a uniform slow axis orientation and retardation in the plane.

Example 1
Synthesis example 1 as component [A] 5 parts by weight of KAYARAD DPHA (manufactured by Nippon Kayaku Co., Ltd.) dipentaerythritol hexaacrylate as component [B] with respect to 100 parts by weight of polymer A1 obtained as component [A] And IRGACURE907 (manufactured by Ciba Specialty Chemicals) (2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one) as component [C] The mixture is dissolved in N-methyl-2-pyrrolidone to obtain a solution having a solid concentration of 2.5% by weight, filtered through a filter having a pore size of 1 μm, and the liquid crystal aligning agent in the present invention (hereinafter referred to as “[liquid crystal aligning agent 1 Was prepared).
Using this liquid crystal aligning agent, a thin film was formed on the substrate in the same manner as in Reference Example 1, and under a nitrogen atmosphere, a wavelength of 365 nm was mainly formed on the surface of this thin film using an ultraviolet polarization exposure apparatus LPU-2000S manufactured by Run Technical Service. A linearly polarized ultraviolet ray of 50 mJ / cm ² was irradiated. Next, a liquid crystal display device was produced in the same manner as in Reference Example 1 except that the direction in which the liquid crystal alignment films were superposed was in accordance with the ultraviolet polarization direction instead of the rubbing direction. It was. When a voltage was applied under the same conditions as in Reference Example 1, a change in light and darkness of the liquid crystal display element was observed in response to ON-OFF of the applied voltage.

Example 2
A thin film is formed on the substrate using the liquid crystal aligning agent 1 in the same manner as in Reference Example 2, and a wavelength of 365 nm is mainly formed on the surface of this thin film using a UV polarized light exposure apparatus LPU-2000S manufactured by LAN TECHNICAL SERVICE under a nitrogen atmosphere. A linearly polarized ultraviolet ray of 50 mJ / cm ² was irradiated. Next, in the same manner as in Reference Example 2, a polymerizable liquid crystal was applied, and further polymerized and solidified to prepare a retardation plate.
In this way, a retardation plate having a retardation at a wavelength of 633 nm of 317 nm was obtained. This retardation plate was colorless and transparent, and had a uniform slow axis orientation and retardation in the plane.

Comparative Example 1
The polymer A1 obtained in Synthesis Example 1 was dissolved in γ-butyrolactone to form a solution having a solid content concentration of 2.5% by weight, and this solution was filtered with a filter having a pore size of 1 μm to obtain a liquid crystal aligning agent (hereinafter referred to as “[ Liquid crystal aligning agent Q ") was prepared.
A liquid crystal display device was produced in the same manner as in Example 1 except that this liquid crystal aligning agent was used. As a result, no liquid crystal alignment was observed.
On the other hand, when the liquid crystal display element was produced in the same procedure as described above except that the ultraviolet irradiation amount was 1 J / cm ² , the liquid crystal orientation was good. When a voltage was applied under the same conditions as in Reference Example 1, a change in light and darkness of the liquid crystal display element was observed in response to ON-OFF of the applied voltage.

Comparative Example 2
A retardation plate was produced in the same manner as in Example 2 except that the liquid crystal aligning agent Q was used. The obtained retardation plate was cloudy and had no retardation.
On the other hand, when a retardation plate was produced in the same procedure as described above except that the ultraviolet irradiation amount was 1 J / cm ² , a retardation plate having a retardation at a wavelength of 633 nm of 317 nm was obtained. This retardation plate was colorless and transparent, and had a uniform slow axis orientation and retardation in the plane.

Comparative Example 3
A liquid crystal display device was produced in the same manner as in Example 1 except that the liquid crystal aligning agent P was used, and no liquid crystal alignment was observed.

Comparative Example 4
A retardation plate was produced in the same manner as in Example 2 except that the liquid crystal aligning agent P was used. The obtained retardation plate was cloudy and had no retardation.

Claims (6)

On the board
[A] a polymer having a structure capable of undergoing a crosslinking reaction by radiation;
[B] a polymerizable compound having an ethylenically unsaturated bond, and
[C] radiation sensitive polymerization initiator,
To form a coating film of be that the liquid crystal aligning agent containing,
A method for forming a liquid crystal alignment film, comprising the step of irradiating the coating film with linearly polarized light or partially polarized radiation . [A] A polymer having a structure capable of undergoing a crosslinking reaction by radiation is represented by the following formula (I):

P ¹ —CH═CH—CO—Q ¹ − (I)

Here, P ¹ represents a monovalent organic group having an aromatic ring, Q ¹ represents a divalent organic group having an aromatic ring,
The following formula (II)

^{-P 2 -CH = CH-CO-} Q 2 ····· (II)

Here, P ² represents a divalent organic group containing an aromatic ring, Q ² represents a monovalent organic group having an aromatic ring,
And the following formula (III)

^{-P 3 -CH = CH-CO-} Q 3 - ····· (III)

Here, P ³ and Q ³ represent a divalent organic group having an aromatic ring,
And a conjugated enone structure represented by the following formula (IV):

Here, Q ⁴ is a monovalent organic group having an aromatic ring, and A ⁴ and B ⁴ are each independently a hydrogen atom, a hydroxyl group, a halogen atom, a cyano group, or a monovalent organic group having 1 to 6 carbon atoms. And b is an integer of 0 to 4, provided that a plurality of B ⁴ may be the same as or different from each other.
A polymer having at least one structure selected from the group consisting of a flavonoid structure obtained by removing one or two hydrogen atoms from a compound represented by the formula: A method for forming a liquid crystal alignment film . [A] A polymer having a structure capable of undergoing a crosslinking reaction by radiation is represented by the following formula (V):

(Wherein S ⁵ is a divalent organic group, T ⁵ is a tetravalent organic group, Z ¹ and Z ² are each independently a hydroxyl group or a monovalent organic group, and Z ¹ and Z ² At least one of the structures represented by the above formulas (I) to (III) and the structure obtained by removing one or two hydrogen atoms from the compound represented by the above formula (IV) And a monovalent organic group containing at least one structure selected from the group consisting of:
The method for forming a liquid crystal alignment film according to claim 2, wherein the polymer has a structure represented by the formula: The liquid crystal aligning film formed by the formation method of the liquid crystal aligning film of Claims 1-3. A liquid crystal display element comprising the liquid crystal alignment film according to claim 4. An optical member obtained by aligning a liquid crystal substance on the liquid crystal alignment film according to claim 4 and then fixing the alignment state.