JP6753392B2 - Polyimide precursor, liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element having the precursor. - Google Patents

Description

The present invention is a polyimide precursor having a relatively large amount of radical generation, which can be used for a vertically oriented liquid crystal display element or the like produced by irradiating a liquid crystal molecule with ultraviolet rays while applying a voltage. The present invention relates to a liquid crystal alignment agent having the above, a liquid crystal alignment film formed by having the liquid crystal alignment agent, and a liquid crystal display element formed by having the liquid crystal alignment film.

The liquid crystal display element of the method (also called the vertical orientation (VA) method) in which the liquid crystal molecules oriented perpendicular to the substrate are made to respond by an electric field is irradiated with ultraviolet rays while applying a voltage to the liquid crystal molecules in the manufacturing process. Some include the process of doing.
In such a vertically oriented liquid crystal display element, a photopolymerizable compound is added to the liquid crystal composition in advance, and a polyimide-based vertically oriented film is used to irradiate the liquid crystal cell with ultraviolet rays while applying a voltage. Therefore, a technique for increasing the response speed of a liquid crystal (PSA (Polymer Sustained Alignment) type element, for example, see Patent Document 1 and Non-Patent Document 1) is known.

In such a PSA type element, the tilting direction of the liquid crystal molecules in response to the electric field is usually controlled by protrusions provided on the substrate, slits provided in the display electrode, or the like, but photopolymerization is performed in the liquid crystal composition. By adding a sex compound and irradiating the liquid crystal cell with ultraviolet rays while applying a voltage, a polymer structure in which the tilted direction of the liquid crystal molecules is memorized is formed on the liquid crystal alignment film, so that only protrusions and slits are used. It is said that the response speed of the liquid crystal display element is faster than the method of controlling the tilt direction of the liquid crystal molecules.

On the other hand, in this PSA type liquid crystal display element, the solubility of the polymerizable compound added to the liquid crystal is low, and there is a problem that it precipitates at a low temperature when the addition amount is increased, but it is good when the addition amount of the polymerizable compound is reduced. It becomes impossible to obtain a good orientation state. Further, the unreacted polymerizable compound remaining in the liquid crystal becomes an impurity (contamination) in the liquid crystal, so that there is a problem that the reliability of the liquid crystal display element is lowered. Further, when the UV irradiation treatment required by the PSA method has a large irradiation amount, the components in the liquid crystal are decomposed, which causes a decrease in reliability.
Furthermore, it has been reported that the response speed of the liquid crystal display element is increased by adding the photopolymerizable compound to the liquid crystal alignment film instead of the liquid crystal composition (SC-PVA type liquid crystal display, for example, non-liquid crystal display). See Patent Document 2).

Japanese Unexamined Patent Publication No. 2003-307720

K.Hanaoka, SID 04 DIGEST, P.1200-1202 K.H Y.-J.Lee, SID 09 DIGEST, P.666-668

In recent years, as the quality of liquid crystal display elements has improved, it has been desired to further increase the response speed of liquid crystals to voltage application. For that purpose, it is necessary that the polymerizable compound reacts efficiently and exerts the orientation-immobilizing ability by irradiation with ultraviolet rays having a long wavelength without decomposing the components in the liquid crystal. Further, it is also necessary that the unreacted polymerizable compound does not remain after the irradiation with ultraviolet rays and the reliability of the liquid crystal display element is not adversely affected.

An object of the present invention is to improve the response speed of a liquid crystal display element obtained by reacting a polymerizable compound in a liquid crystal and / or a liquid crystal alignment film without the above-mentioned problems of the prior art. It is an object of the present invention to provide a liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal display element capable of forming a liquid crystal.
More specifically, an object of the present invention is to provide a polyimide precursor having a relatively large amount of radical generation, and the polyimide precursor promotes the reaction of a polymerizable compound to efficiently adjust the pretilt angle in a liquid crystal. It is a desired value to improve the response speed of the liquid crystal display element.

As a result of diligent studies, the present inventors have made a specific structure in which radicals are generated by irradiation with ultraviolet rays and a relatively large amount of the radicals is generated in the polyimide precursor with respect to the polymer constituting the liquid crystal aligning agent. Reaction of a polymerizable compound in a liquid crystal display element obtained by using a step of reacting a polymerizable compound in a liquid crystal and / or a liquid crystal alignment film by introducing and using a liquid crystal aligning agent having the polyimide precursor. We have found that the above-mentioned problems can be achieved by enhancing the properties, and completed the invention described in detail below.

<1> A polyimide precursor using a first photoradical generating diamine, except that the first photoradical generating diamine is replaced with a second photoradical generating diamine represented by the formula (1). The polyimide precursor is characterized in that the amount of radicals generated during light irradiation under the same conditions is larger than that of the second polyimide precursor formed under the same conditions as the polyimide precursor.

<2> In the above <1>, the wavelength of light at the time of light irradiation is preferably 300 nm to 400 nm.
<3> In the above <1> or <2>, the first photoradical generating diamine is preferably 0.1 to 100 mol% in 100 mol% of the total diamines constituting the polyimide precursor.
<4> In the above <1> to <3>, the first photoradical generating diamine is the formula (A).
(In the formula, Ar represents an aromatic hydrocarbon group which may have a substituent and represents
R ¹⁰¹ represents a divalent organic group
R ^{102 to} R ¹⁰⁴ each independently represent a monovalent organic group)
It is preferable to have the structure of.

<5> In <4> above, -R ^101- is -T ₁ -S-T _2-
(In the formula,
T ₁ and T ₂ are independent, single bond, -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, -CH ₂ O-, -N (CH ₃ ). -, -CON (CH ₃ )-, or -N (CH ₃ ) CO-,
S is a single bond, or an alkylene group having 1 to 20 carbon atoms substituted with an unsubstituted or fluorine atom (-CH _2- or -CF _2- in the alkylene group is -CH = CH-, or the following. It may be replaced with a group selected from the group G (where the groups selected from the group G are not adjacent to each other) (group G: -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, divalent carbocycle or divalent heterocycle)))
It should be represented by.

<6> In the above <4> or <5>, any one of R ^{102 to} R ¹⁰⁴ has -OR ¹¹¹ (R ¹¹¹ has 1 to 20 carbon atoms substituted or substituted with a fluorine atom. Linear or branched or cyclic alkyl group (-CH _2- or -CF _2- in the alkyl group is -CH = CH-, or a group selected from the next group G (however, selected from the group G). Groups may be replaced with (groups G: -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, divalent carbocycles or divalent groups. It may be substituted with a valence heterocycle)) and
The other two are independently linear or branched or cyclic alkyl groups with 1 to 20 carbon atoms, -OR ¹¹² (R ¹¹² is unsubstituted or substituted with a fluorine atom and has 1 to 20 carbon atoms. Represents a group selected from the group consisting of a linear or branched or cyclic alkyl group, an aryl group having 6 to 20 carbon atoms which may have a substituent), a benzyl group, or a phenethyl group. (If the other two are the alkyl group or -OR ¹¹² , they may be bonded to each other to form a ring).

<7> In any of the above <4> to <6>, Ar is preferably a phenylene group.
<8> In any of the above <1> to <7>, the first photoradical generating diamine is the following formula (2) (in the formula, Ar and R ^{101 to} R ¹⁰⁴ have the same definition as described above). It should be represented by.

<9> In any of the above <1> to <8>, the first photoradical generating diamine is preferably represented by the following formula (3).

<10> In any of the above <1> to <9>, it is preferable that the polyimide precursor further has a side chain for vertically orienting the liquid crystal.
<11> In any of the above <1> to <10>, it is preferable that the polyimide precursor further has a side chain containing a photoreactive group in the structure.
<12>
A polyimide obtained by imidizing any of the polyimide precursors <1> to <11>.

<13> A liquid crystal alignment agent having the polyimide precursor according to any one of <1> to <11> and / or the polyimide according to <12>.
<14> In the above <13>, a liquid crystal display element obtained by containing a polymerizable compound in a liquid crystal and / or a liquid crystal alignment film and reacting the polymerizable compound by irradiating ultraviolet rays while applying a voltage. It is good to be used for the production of.
<15> A liquid crystal alignment film formed by having the liquid crystal alignment agent of <13> or <14>.
<16> A liquid crystal display element including the liquid crystal alignment film of <15>.

<17> The following formula (A)
(In the formula, Ar represents an aromatic hydrocarbon group which may have a substituent and represents
R ¹⁰¹ represents a divalent organic group
R ^{102 to} R ¹⁰⁴ each independently represent a monovalent organic group)
A diamine having a structure represented by.

<18> In <17> above, -R ^101- is -T ₁ -S-T _2-
(In the equation, T ₁ and T ₂ are independent, single bond, -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, -CH ₂ O-, -N. (CH ₃ )-, -CON (CH ₃ )-, or -N (CH ₃ ) CO-
S is a single bond, or an alkylene group having 1 to 20 carbon atoms substituted with an unsubstituted or fluorine atom (-CH _2- or -CF _2- in the alkylene group is -CH = CH-, or the following. It may be replaced with a group selected from the group G (where the groups selected from the group G are not adjacent to each other) (group G: -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, divalent carbocycle or divalent heterocycle)))
It should be represented by.

<19> In the above <17> or <18>,
Any one of R ^{102 to} R ¹⁰⁴ is -OR ¹¹¹ (R ¹¹¹ is a linear or branched or cyclic alkyl group having 1 to 20 carbon atoms substituted with an unsubstituted or fluorine atom (alkyl). -CH _2- or -CF _{2- in the} group is replaced with -CH = CH- or a group selected from the next group G (however, the groups selected from the group G are not adjacent to each other). May be substituted with (group G: -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, divalent carbon ring or divalent heterocycle). And
The other two are independently linear or branched or cyclic alkyl groups with 1 to 20 carbon atoms, -OR ¹¹² (R ¹¹² is unsubstituted or substituted with a fluorine atom and has 1 to 20 carbon atoms. Represents a group selected from the group consisting of a linear or branched or cyclic alkyl group, an aryl group having 6 to 20 carbon atoms which may have a substituent), a benzyl group, or a phenethyl group. (If the other two are the alkyl group or -OR ¹¹² , they may be bonded to each other to form a ring).

<20> The diamine according to any one of <17> to <19> may be represented by the following formula (2) (Ar and R ^{101 to} R ¹⁰⁴ have the same definitions as described above).

<21> The diamine of any of <17> to <20> has the same definition as described above in the following formulas (4) (R ¹⁰³ and R ¹⁰⁴ , and R ¹¹¹ ), and X ¹⁰¹ is a single bond or CO. It is better to be represented by).

<22> The diamine according to any one of <17> to <21> is preferably selected from the group consisting of the following formulas (3) to (3) -12.

<23> In the following formula (2) (in the formula, Ar represents an aromatic hydrocarbon group which may have a substituent, R ¹⁰¹ represents a divalent organic group, and R ^{102 to} R ¹⁰⁴ are independent of each other. Represents a monovalent organic group)
Diamine represented by.

<24> A diamine represented by the following formula (3).

<25> A diamine selected from the group consisting of the following formulas (3) to (3) -12.

<26> A polyimide precursor using any of the diamines <17> to <25> above.
<27> In the above <26>, the diamine of any one of the above <17> to <25> is preferably 0.1 to 100 mol% in 100 mol% of the total diamines constituting the polyimide precursor.
<28> The polyimide precursor of <26> or <27> may further have a side chain for vertically orienting the liquid crystal.
<29> In the above <28>, the side chain that vertically orients the liquid crystal is the following formula [II-1] (in the formula [II-1], X ¹ is a single bond, − (CH ₂ ) _a − ( a represents an integer of 1 to 15), -O-, -CH ₂ O-, -COO- or OCO-. X ² is a single bond or (CH ₂ ) _b- (b is 1 to 15). Represents an integer). X ³ represents a single bond, − (CH ₂ ) _c − (c is an integer from 1 to 15), −O−, −CH ₂ O−, −COO− or OCO−. X ⁴ is represented by a divalent cyclic group selected from a benzene ring, a cyclohexane ring, and a heterocycle, and any hydrogen atom of these cyclic groups is an alkyl group having 1 to 3 carbon atoms and 1 to 3 carbon atoms. alkoxyl group, a fluorine-containing alkyl group having 1 to 3 carbon atoms may be substituted with a fluorine-containing alkoxyl group or a fluorine atom having 1 to 3 carbon atoms, further, X ⁴ is 17 carbon atoms having a steroid skeleton It may be a divalent organic group selected from 51 organic groups. X ⁵ represents a divalent cyclic group selected from a benzene ring, a cyclohexane ring and a heterocycle, and any hydrogen atom on these cyclic groups. Is substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom. Good. N represents an integer from 0 to 4. X ⁶ is an alkyl group having 1 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxyl group having 1 to 18 carbon atoms, or 1 to 18 carbon atoms. Represents the fluorine-containing alkoxyl group of.)
And [II-2]
(In the formula [II-2], X ⁷ is a single bond, −O−, −CH ₂ O−, −CONH−, −NHCO−, −CON (CH ₃ ) −, −N (CH ₃ ) CO−. , -COO- or OCO-. X ⁸ represents an alkyl group having 8 to 22 carbon atoms or a fluorine-containing alkyl group having 6 to 18 carbon atoms.
It should be at least one selected from.

<30> The polyimide precursor according to any one of <26> to <29> preferably further has a side chain containing a photoreactive group in the structure.
<31> In <30> above, the side chain containing a photoreactive group in the structure is
The following formula [III]
(In formula [III], R ⁸ is a single bond, -CH _2- , -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, -CH ₂ O-,- Represents N (CH ₃ )-, -CON (CH ₃ )-, or -N (CH ₃ ) CO-. R ⁹ is a single bond, alkylene having 1 to 20 carbon atoms which may be substituted with a fluorine atom. Representing a group, the alkylene group −CH ₂ − may be optionally substituted with −CF ₂ − or −CH = CH −, and if any of the following groups are not adjacent to each other, they are substituted with these groups. it may be; -O -, - COO -, - OCO -, - NHCO -, - CONH -, - NH-, a divalent carbocyclic or heterocyclic ^{.R 10} of the following formulas ^R 10 -1 to It represents a photoreactive group selected from the group consisting of R ^{10 -7.)}
Or formula (IV)
(Y ₁ represents -CH _2- , -O-, -CONH-, -NHCO-, -COO-, -OCO-, -NH-, or -CO-. Y ₂ has 1 to 30 carbon atoms. It is an alkylene group, a divalent carbocyclic ring or a heterocyclic ring, and one or more hydrogen atoms of the alkylene group, the divalent carbocyclic ring or the heterocyclic ring may be substituted with a fluorine atom or an organic group. _{For 2} , -CH _2- may be substituted with these groups if the following groups are not adjacent to each other; -O-, -NHCO-, -CONH-, -COO-, -OCO-,- _{NH -, - NHCONH -, -} CO-.Y 3 is, -CH 2 -, - O - , - CONH -, - NHCO -, - COO -, - OCO -, - NH -, - CO-, or a single Represents a bond. Y ₄ represents a cinnamoyl group. Y ₅ is a single bond, an alkylene group having 1 to 30 carbon atoms, a divalent carbocyclic ring or a heterocyclic ring, and the alkylene group, a divalent carbocyclic ring or a heterocyclic ring. one or more hydrogen atoms may .Y ₅ be substituted with a fluorine atom or an organic group, if the next group is not adjacent to each other, -CH 2 _- is substituted by these groups May; -O-, -NHCO-, -CONH-, -COO-, -OCO-, -NH-, -NHCONH-, -CO-. Y ₆ is a photopolymerizable group which is an acrylic group or a methacryl group. Show.)
It should be represented by.

<31> A polyimide obtained by imidizing any of the polyimide precursors <26> to <30> above.
<32> A liquid crystal alignment agent having the polyimide precursor according to any one of <26> to <31> and / or the polyimide according to <31>.
<33> In the above <32>, a liquid crystal display element obtained by containing a polymerizable compound in a liquid crystal and / or a liquid crystal alignment film and reacting the polymerizable compound by irradiating ultraviolet rays while applying a voltage. It is good to be used for the production of.
<34> A liquid crystal alignment film formed by having the liquid crystal alignment agent of <32> or <33>.
<35> A liquid crystal display element including the liquid crystal alignment film of <34>.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a polyimide precursor having a relatively large amount of radical generation.
Further, according to the present invention, by using a liquid crystal alignment agent having the polyimide precursor and / or a liquid crystal alignment film formed by having the liquid crystal alignment agent, even if the irradiation amount of ultraviolet rays is relatively low, A desired pre-tilt angle can be obtained in a liquid crystal, and along with this, a vertically oriented liquid crystal display element having a high response speed, particularly a PSA type liquid crystal display element, can be provided.

The present invention relates to a polyimide precursor having a relatively large amount of radical generation, a diamine constituting the polyimide, a liquid crystal alignment agent having the polyimide precursor, a liquid crystal alignment film formed by having the liquid crystal alignment agent, and the same. Provided is a liquid crystal display element. Hereinafter, they will be described in order.
<Polyimide precursor with a relatively large amount of radicals generated>
The present invention provides a polyimide precursor having a relatively large amount of radicals generated.
Specifically, the present invention provides a polyimide precursor using the first photoradical generating diamine.
The polyimide precursor using the first photoradical generating diamine was formed under the same conditions except that the first photoradical generating diamine was replaced with the second photoradical generating diamine represented by the formula (1). It is characterized in that the amount of radicals generated during light irradiation under the same conditions is larger than that of the second polyimide precursor.
Here, the wavelength of light "when irradiated with light under the same conditions" is preferably 300 nm to 400 nm, preferably 310 to 380 nm, and more preferably 350 to 370 nm.

In addition, in this specification, a "polyimide precursor" means the thing obtained by reacting a diamine component with a tetracarboxylic dianhydride component.
Further, in the present specification, "a polyimide precursor using ~ ~ diamine" or "a polyimide precursor is formed using ~ ~ diamine" means "~ ~ diamine" as a raw material of the polyimide precursor. It means that it is used. Here, the "diamine" includes a case where it is a part or a whole of a raw material.
In the present specification, "~ ~ diamine constituting the polyimide precursor" means that "~ ~ diamine" is used as a raw material of the polyimide precursor to form the polyimide precursor. Here, the "diamine" includes a case where it is a part or a whole of a raw material.

In the polyimide precursor of the present invention, the first photoradical generating diamine is 0.1 to 100 mol%, preferably 10 to 80 mol%, more preferably 30% of the total diamine constituting the polyimide precursor. It should be ~ 50 mol%.

The first photoradical generating diamine is of formula (A).
(In the formula, Ar represents an aromatic hydrocarbon group which may have a substituent and represents
R ¹⁰¹ represents a divalent organic group
R ^{102 to} R ¹⁰⁴ each independently represent a monovalent organic group)
It is preferable to have the structure of.

-R ^101- is preferably a group represented by -T _1- S-T _2- .
Here, T ₁ and T ₂ are independently single-bonded, -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, -CH ₂ O-, -N ( CH ₃ )-, -CON (CH ₃ )-, or -N (CH ₃ ) CO-
S is a single bond, or an alkylene group having 1 to 20 carbon atoms substituted with an unsubstituted or fluorine atom (-CH _2- or -CF _2- in the alkylene group is -CH = CH-, or the following. It may be replaced with a group selected from the group G (where the groups selected from the group G are not adjacent to each other) (group G: -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, divalent carbocycle or divalent heterocycle)).

Any one of R ^{102 to} R ¹⁰⁴ is -OR ¹¹¹ (R ¹¹¹ is a linear or branched or cyclic alkyl group having 1 to 20 carbon atoms substituted with an unsubstituted or fluorine atom (alkyl). -CH _2- or -CF _{2- in the} group is replaced with -CH = CH- or a group selected from the next group G (however, the groups selected from the group G are not adjacent to each other). May be substituted with (group G: -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, divalent carbon ring or divalent heterocycle). And
The other two are independently linear or branched or cyclic alkyl groups with 1 to 20 carbon atoms, -OR ¹¹² (R ¹¹² is unsubstituted or substituted with a fluorine atom and has 1 to 20 carbon atoms. Represents a group selected from the group consisting of a linear or branched or cyclic alkyl group, an aryl group having 6 to 20 carbon atoms which may have a substituent), a benzyl group, or a phenethyl group. (If the other two are the alkyl group or -OR ¹¹² , they may be bonded to each other to form a ring).

Ar is preferably a group selected from phenylene, naphthylene and biphenylene.
Since Ar to which the carbonyl is bonded is involved in the absorption wavelength of ultraviolet rays, a structure having a long conjugated length such as naphthylene or biphenylene is preferable when the wavelength is lengthened. Ar may be substituted with a substituent, and such a substituent is preferably an electron-donating organic group such as an alkyl group, a hydroxyl group, an alkoxy group, or an amino group.
However, when Ar has a structure such as naphthylene or biphenylene, the solubility becomes poor and the difficulty of synthesis becomes high. Therefore, if the wavelength of ultraviolet rays is in the range of 300 nm to 400 nm, preferably 310 to 380 nm, sufficient characteristics can be obtained even with a phenyl group, so that a phenyl group is most preferable.

The first photoradical generating diamine is preferably represented by the following formula (2) (Ar and R ^{101 to} R ¹⁰⁴ have the same definition as described above). The diaminobenzene may have a structure of either o-phenylenediamine, m-phenylenediamine, or p-phenylenediamine, but in terms of reactivity with acid dianhydride, m-phenylenediamine or p- Phenylenediamine is preferred.

In particular, the first photoradical generating diamine is represented by the following formula (4) (R ¹⁰³ and R ¹⁰⁴ , and R ¹¹¹ have the same definition as described above, and X ¹⁰¹ represents a single bond or CO). It should be diamine.

Specifically, the following formulas (3) to (3) -12 can be mentioned as the first photoradical generating diamine, but the diamine is not limited thereto. The first photoradical generating diamine is particularly preferably a diamine represented by the formula (3).

<Side chain that orients the liquid crystal vertically>
The polyimide precursor of the present invention preferably further has a side chain that orients the liquid crystal vertically.
The side chain that orients the liquid crystal vertically is represented by the following formula [II-1] or formula [II-2].
Wherein ^{[II-1], X 1} ~X 6, and n are as defined above. In the formula ^{[II-2], X 7} , X 8 are as defined above.

Among them, X ¹ is a single bond, − (CH ₂ ) _a − (a is an integer of 1 to 15), −O −, −CH ₂ O from the viewpoint of availability of raw materials and ease of synthesis. -Or COO- is preferred, and more preferred are single bonds,-(CH ₂ ) _a- (a is an integer of 1-10), -O-, -CH ₂ O- or COO-. Among them, X ² is preferably a single bond or (CH ₂ ) _b − (b is an integer of 1 to 10). Among them, X ³ has a single bond, − (CH ₂ ) _c − (c is an integer of 1 to 15), −O −, −CH ₂ O− or COO− from the viewpoint of ease of synthesis. Preferred and more preferred are single bonds, − (CH ₂ ) _c − (c is an integer of 1-10), −O−, −CH ₂ O− or COO−.

Among them, X ⁴ is for ease of synthesis, a benzene ring, an organic group having 17 to 51 carbon atoms and having a hexane ring or steroid skeleton cyclohexylene preferred. X ⁵ is, inter alia, hexane ring to a benzene ring or a cycloalkyl are preferred. Among them, n is preferably 0 to 3, and more preferably 0 to 2 from the viewpoint of availability of raw materials and ease of synthesis.
Of these, X ⁶ is preferably an alkyl group having 1 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 18 carbon atoms, or a fluorine-containing alkoxyl group having 1 to 10 carbon atoms. More preferably, it is an alkyl group having 1 to 12 carbon atoms or an alkoxyl group having 1 to 12 carbon atoms. Particularly preferably, it is an alkyl group having 1 to 9 carbon atoms or an alkoxyl group having 1 to 9 carbon atoms.

A preferable combination of X ¹ , X ² , X ³ , X ⁴ , X ⁵ , X ⁶ and n in the formula [II-1] is from page 13 of International Publication WO2011 / 132751 (published 2011.10.27). The same combinations as (2-1) to (2-629) listed in Tables 6 to 47 on page 34 can be mentioned. In each table of International Publication, ^X 1 to X ⁶ in the present invention is shown as Y1 to Y6, Y1 to ^Y6, it shall read X 1 to X ^6.
Further, in (2-605) to (2-629) published in each table of the International Publication, the organic group having a steroid skeleton and having 17 to 51 carbon atoms in the present invention has a steroid skeleton and has 12 to 12 carbon atoms. Although it is shown as 25 organic groups, an organic group having a steroid skeleton and having 12 to 25 carbon atoms shall be read as an organic group having a steroid skeleton and having 17 to 51 carbon atoms. Among them, (2-25) to (2-96), (2-145) to (2-168), (2-217) to (2-240), (2-268) to (2-315) , (2-364) to (2-387), (2-436) to (2-483) or (2-603) to (2-615) are preferred. Particularly preferred combinations are (2-49) to (2-96), (2-145) to (2-168), (2-217) to (2-240), (2-603) to (2-603). 606), (2-607) to (2-609), (2-611), (2-612) or (2-624).

In the formula [II-2], among them, X ⁷ is preferably single bond, -O-, -CH ₂ O-, -CONH-, -CON (CH ₃ )-or COO-, and more preferably simple. Bond, -O-, -CONH- or COO-. Of these, X ⁸ is preferably an alkyl group having 8 to 18 carbon atoms.

As the side chain for vertically aligning the liquid crystal, it is preferable to use the structure represented by the formula [II-1] from the viewpoint of increasing the orientation of the liquid crystal and stabilizing it.
The ability of the polyimide precursor having a side chain for vertically orienting the liquid crystal to orient the liquid crystal vertically depends on the structure of the side chain for vertically orienting the liquid crystal, but generally, the side for vertically orienting the liquid crystal. The ability to orient the liquid crystal vertically increases as the amount of chains increases, and decreases as the amount of chains decreases. In addition, having an annular structure tends to have a higher ability to orient the liquid crystal vertically as compared with one having no annular structure.

<Photoreactive side chain>
The polyimide precursor of the present invention may have a photoreactive side chain. The photoreactive side chain has a functional group (also referred to as a photoreactive group in the present specification) that can react by irradiation with light such as ultraviolet rays (UV) to form a covalent bond. That is, the polyimide precursor of the present invention preferably further has a side chain containing a photoreactive group in the structure.
The photoreactive side chain may be directly bonded to the main chain of the polymer, or may be bonded via a bonding group. The photoreactive side chain is represented by, for example, the following formula [III].

In formula [III], R ⁸ , R ⁹ , and R ¹⁰ are as defined above. Of these, R ⁸ is preferably single-bonded, -O-, -COO-, -NHCO, or -CONH-. R ⁹ can be formed by an ordinary organic synthetic method, but from the viewpoint of easiness of synthesis, a single bond or an alkylene group having 1 to 12 carbon atoms is preferable.

Specific examples of the divalent carbon ring or heterocycle that replaces any −CH ₂ − of R ⁹ are as follows.

R ¹⁰ is preferably a methacrylic group, an acrylic group or a vinyl group from the viewpoint of photoreactivity.
The abundance of photoreactive side chains is preferably in the range in which the response speed of the liquid crystal can be increased by reacting with irradiation with ultraviolet rays to form a covalent bond, and in order to further increase the response speed of the liquid crystal. , It is preferable that the number is as large as possible without affecting other characteristics.

<Polyimide precursor forming a liquid crystal alignment agent>
The method for producing a polyimide precursor using the first photoradical generating diamine and a polyimide obtained by imidizing the polyimide precursor is not particularly limited. For example, a method of polymerizing the first photoradical generating diamine and the tetracarboxylic dianhydride, a method of polymerizing the first photoradical generating diamine and other diamines and the tetracarboxylic dianhydride, and the like can be mentioned.

The same method as described above can be mentioned as a method for producing a polyimide precursor further having a side chain and / or a photoreactive side chain for vertically orienting the liquid crystal, and a polyimide obtained by imidizing the polyimide precursor. Similarly, the preferred method also comprises a first photoradical-generating diamine containing a side chain that orients the liquid crystal vertically and / or a first photoradical-generating diamine containing a photoreactive side chain and a tetracarboxylic dianhydride. A method of polymerizing the anhydride is preferable.

<Synthesis of the first photoradical generating diamine>
In the present invention, the first photoradical generating diamine is a dinitro form through each step, or a mononitro form having an amino group with a protecting group that can be removed in the reduction step, or a diamine, which is usually used. It can be obtained by converting a nitro group to an amino group or deprotecting a protecting group in the reaction.

The method for synthesizing the first method for synthesizing the photoradical generating diamine of the present invention is not particularly limited. For example, in the following formulas (5) (formula (5), Ar, R ^{101 to} R ¹⁰⁴ are the above formulas (A). ) Is the same as each definition in)), and the dinitro compound is further reduced to convert it into an amino group.

The method for reducing the nitro group is not particularly limited, but for example, palladium-carbon, platinum oxide, Raney nickel, platinum-carbon, rhodium-alumina, platinum sulfide carbon, reduced iron, iron chloride, tin, tin chloride, and zinc. There is a method of using hydrogen gas, hydrazine, hydrogen chloride, ammonium chloride, etc. as a catalyst.
When the structure has an unsaturated binding site, a reduction method in which the unsaturated bond is not reduced can be used.
As long as the unsaturated bond is not reduced, the reduction method is not particularly limited, and for example, reduced iron, tin, tin chloride, poisoned palladium-carbon, and poisoned platinum-carbon are used as catalysts, and hydrogen gas is used. , Hydrazine, hydrogen chloride, ammonium chloride, etc.
When the structure has a benzyl binding site, a reduction method in which the benzyl group is not cleaved can be used.
As long as the benzyl group is not cleaved, the reduction method is not limited, but for example, platinum black, rhodium-alumina, platinum carbon sulfide, reduced iron, iron chloride, tin, tin chloride, zinc, etc. are used as catalysts, and hydrogen gas, There is a method using hydrazine, hydrogen chloride, ammonium chloride, etc.

As the reaction solvent, a solvent that does not affect the reaction can be used. For example, ester solvents such as ethyl acetate and methyl acetate, aromatic hydrocarbon solvents such as toluene and xylene, aliphatic hydrocarbon solvents such as n-hexane, n-heptane and cyclohexane, 1,2-dimethoxyethane, tetrahydrofuran, Ether solvents such as dioxane, alcohol solvents such as methanol and ethanol, ketone solvents such as 2-butanone and 4-methyl-2-pentanone, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl Examples thereof include aprotic polar solvents such as -2-pyrrolidone and dimethylsulfoxide, and water. These organic solvents can be used alone or in combination of two or more.

The reaction temperature can be set to a temperature at which the reaction proceeds efficiently as long as it is below the boiling point of the solvent used without decomposing the raw materials and products. Specifically, a temperature from −78 ° C. to below the boiling point of the solvent is preferable, and a temperature from 0 ° C. to below the boiling point of the solvent is more preferable from the viewpoint of ease of synthesis.

The method for synthesizing the compound of the formula (5) is not particularly limited, but for example, when R ¹⁰² of the formula (5) is OR ¹¹¹ (R ¹¹¹ is the same as the definition described in <6> above). Synthesizes the dinitro compound represented by the following formula (6) (in the formula (6), Ar, R ¹⁰¹ , R ¹⁰³ , and R ¹⁰⁴ are the same as the respective definitions in the above formula (A)). Further, a method of introducing a substituent into the OH group can be mentioned.

The method for introducing a substituent into the OH group is not particularly limited, and for example, L ¹ in the following formula (7) (formula (7) is a halogen, an alkane sulfonyloxy group, or an allene sulfonyloxy group. R ¹¹¹ is the same as the definition described in <6> above), and examples thereof include a method of reacting an alkyl halide or an alkyl sulfonic acid ester under neutral conditions or alkaline conditions.

The reaction solvent and reaction temperature are in accordance with the above description, but alcohol solvents and water are not preferable because they may react with raw materials.
Examples of the alkyl halide include methyl iodide, ethyl iodide, n-propyl iodide, n-butyl iodide, n-octadecyl iodide, benzyl iodide, bromoethane, 1-bromopropane, 1-bromobutane, and 1-bromo. Octadecan, benzyl bromide, chloroethane, 1-chloropropane, 1-chlorobutane, 1-chlorooctadecan, benzyl chloride, methyl methanesulfonate, ethyl methanesulfonate, n-propyl methanesulfonic acid, n-butyl methanesulfonic acid, methanesulfonic acid Examples thereof include n-octadecyl and benzyl methanesulfonate.

When the compound represented by the formula (5) is represented by the following formula (8), the compound represented by the above formula (6) and the vinyl ether represented by the following formula (9) are absent. Examples thereof include a synthetic method in which the reaction is carried out under a catalyst or an acid catalyst.
In the formula (8), Ar, R ¹⁰¹ , R ¹⁰³ , and R ¹⁰⁴ are the same as the respective definitions in the above formula (A), and R ²¹¹ is a carbon substituted or substituted with a fluorine atom. A linear or branched or cyclic alkyl group having 1 to 18 atoms (-CH _2- or -CF _2- in the alkyl group is -CH = CH- or a group selected from the following group G (however, however). The groups selected from the group G may be replaced with (groups G: -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, divalent). It may be substituted with a carbon ring or a divalent heterocycle).).
In the formula ^{(9), R 211} is, in the above formula (8) ^is the same as the definition of ^{R 211.}

Examples of the vinyl ether include ethyl vinyl ether, n-butyl vinyl ether, n-octadecyl vinyl ether, diethylene glycol monovinyl ether and the like.
Examples of the acid catalyst include p-toluenesulfonic acid, pyridinium p-toluenesulfonic acid, and methanesulfonic acid.
The compound represented by the formula (5) is the following formula (10) (in the formula (10), Ar, R ¹⁰¹ , R ¹⁰³ , and R ¹⁰⁴ are the same as the respective definitions in the above formula (A)). In the case of being represented by, a synthetic method in which the compound represented by the above formula (6) and 3,4-dihydropyran are reacted without a catalyst or under an acid catalyst can be mentioned.

When the compound represented by the formula (5) is represented by the following formula (11) (in the formula (11), Ar, R ^{102 to} R ¹⁰⁴ are the same as the respective definitions in the above formula (A). Yes, S and T ₂ are the same as the definition described in <5> above), and the dinitro compound represented by the following formula (12) (where L ² is a halogen in the formula (12)) , (13) (In the formula (13), Ar, R ^{102 to} R ¹⁰⁴ are the same as the respective definitions in the above formula (A), and S and T ₂ are the definitions described in the above <5>. A method of reacting with an alcohol represented by) in the presence of an alkali can be mentioned. The reaction solvent and reaction temperature are in accordance with the above description, but an alcohol solvent, a protic solvent such as water can be used as long as they do not react with the raw materials.

Examples of the compound represented by the formula (12) include 2,4-dinitrofluorobenzene, 2,4-dinitrochlorobenzene, 2,4-dinitrobromobenzene, 2,4-dinitroiodobenzene, and 3,5-dinitrochlorobenzene. Examples thereof include 3,5-dinitroiodobenzene, 3,4-dinitrofluorobenzene, 3,4-dinitrochlorobenzene and 2,3-dinitrochlorobenzene.
The method for synthesizing the compound represented by the formula (13) is not particularly limited. For example, when R ¹⁰² of the formula (13) is represented by OR ¹¹¹ , the following formulas (14) (formula (14)) are used. , Ar, R ¹⁰³ , and R ¹⁰⁴ are the same as the respective definitions in the above formula (A), and S and T ₂ are the same as the definitions described in the above <5>). Examples thereof include a method in which the primary hydroxyl group is protected by a protecting group, a substituent is introduced into the remaining tertiary hydroxyl group, and then the protecting group of the primary hydroxyl group is deprotected.

Examples of the compound represented by the formula (14) include 2-hydroxy-1- (4- (hydroxymethyl) phenyl) -2-methyl-1-propanone and 1-hydroxycyclohexyl (4- (2-hydroxyethyl) phenyl). )) Ketone, 1-hydroxycyclohexyl (4-hydroxyphenyl) ketone, 2-hydroxy-1-(4-((2-hydroxyethyl) thio) phenyl) -2-methyl-1-propanol, 2-hydroxy-1 -(4-Hydroxyphenyl) -2-methyl-1-propanol, 2-hydroxy-1- (4- (2-hydroxyethoxy) phenyl) -2-methyl-1-propanone, 1- (3,4-dihydroxy) Phenyl) -2-hydroxy-2-methyl-1-propanone, 2-hydroxy-1-(4- (2-hydroxyethyl) phenyl) -2-methyl-1-propanone, 2-hydroxy-1- (4-) (3-Hydroxypropyl) phenyl) -2-methyl-1-propanone and the like can be mentioned.
The protecting group is not particularly limited, but for example, a tetrahydropyranyl group, a benzyl group, a p-methoxybenzyl group, a methoxymethyl group, a trimethylsilyl group, a t-butyldimethylsilyl group, an acetyl group, a benzoyl group, a trityl group and the like. Can be mentioned.

The method for introducing a tertiary hydroxyl group after protecting the primary hydroxyl group of the compound represented by the formula (14) is not particularly limited. For example, when R ^{102 of the} formula (5) is OR ¹¹¹ , the formula is The same conditions as in the case of synthesizing the compound represented by the formula (5) from the compound represented by (6) can be used.
The method for deprotecting each protecting group is not particularly limited, and general deprotection reaction conditions can be applied.

The compounds represented by the formula (5) are defined in the following formula (15) (in the formula (15), Ar, R ^{102 to} R ¹⁰⁴ are the same as the respective definitions in the above formula (A), and S, T. ₂ is the same as the definition described in <5> above), where L ¹ is the same as L ¹ in the following equation (16) (in equation (16), L ¹ is the same as in equation (7)). A method of reacting the dinitro compound represented by (definition) with the alcohol represented by the formula (13) in the presence of an alkali can be mentioned. The reaction solvent and reaction temperature are in accordance with the above description, but an alcohol solvent, a protic solvent such as water can be used as long as they do not react with the raw materials.

Examples of the compound represented by the formula (16) include 3,5-dinitrobenzyl chloride, methanesulfonic acid (3,5-dinitrobenzyl), 2,4-dinitrobenzyl chloride, and methanesulfonic acid (2,4-dinitrobenzyl). ) And so on.

The compound represented by the formula (5) is the following formula (17) (in the formula (17), Ar, R ^{102 to} R ¹⁰⁴ , S, T ₂ are the same as the definitions described in <5> above). in the case where expressed by the following formulas (18) (formula (18) ^{L 2} in the formula (12) is the same definition as ^{L 2} in) and dinitro compound represented by the formula (13) The alcohol represented by the formula (19) is reacted in the presence of an alkali, or the dinitro compound represented by the formula (19) is reacted with the alcohol represented by the formula (13) in the presence of a dehydration condensing agent. The method etc. can be mentioned. The reaction solvent and reaction temperature are in accordance with the above description, but an alcohol solvent, a protic solvent such as water can be used as long as they do not react with the raw materials.

Examples of the compound represented by the formula (18) include 3,5-dinitrobenzoyl chloride and the like.
Examples of the compound represented by the formula (19) include 3,5-dinitrobenzoic acid.
Examples of the dehydration condensing agent include dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, diisopropylcarbodiimide, 1,1'-carbonyldiimidazole, and bis (2-oxo-3-oxazolinidyl) phosphinic acid. Chloride, di-2-pyridyl carbonate, triphenylphosphite, dimethoxy-1,3,5-triazinylmethylmorpholinium, O- (benzotriazole-1-yl) -N, N, N', N'-tetramethyluronium tetrafluoroborate, O- (benzotriazole-1-yl) -N, N, N', N'-tetramethyluronium hexafluorophosphate, (2,3-dihydro-2) -Tioxo-3-benzoxazolyl) Diphenyl phosphonate and the like can be mentioned.

<Polyimide precursor with side chains that orient liquid crystals vertically>
In the method of introducing a side chain for vertically aligning the liquid crystal into the polyimide precursor, it is preferable to use a diamine having a specific side chain structure as a part of the diamine component. In particular, it is preferable to use a diamine represented by the following formula [2] (also referred to as a specific side chain diamine compound).

In the formula [2], X represents the structure represented by the above formula [II-1] or the formula [II-2], n represents an integer of 1 to 4, and 1 is particularly preferable.
As the specific side chain diamine, it is preferable to use the diamine represented by the following formula [2-1] from the viewpoint that a high and stable vertical orientation of the liquid crystal can be obtained.

X ¹ , X ² , X ³ , X ⁴ , X ⁵ , and n in the above formula [2-1] are the same as those defined in the above formula [II-1], respectively, and each of them. The preferred ones are also the same as those defined in each of the above formulas [II-1].
In the formula [2-1], m is an integer of 1 to 4. It is preferably an integer of 1.
Specific examples of the specific side chain diamine include structures represented by the following formulas [2a-1] to [2a-31].
In the formula, R ¹ represents -O-, -OCH _2- , -CH ₂ O-, -COOCH _2- or CH ₂ OCO-, and R ² is a linear or branched form having 1 to 22 carbon atoms. An alkyl group, a linear or branched alkoxyl group having 1 to 22 carbon atoms, a linear or branched linear or branched alkoxyl group having 1 to 22 carbon atoms, or a fluorine-containing alkoxyl group.
R ³ indicates -COO-, -OCO-, -CONH-, -NHCO-, -COOCH _2- , -CH ₂ OCO-, -CH ₂ O-, -OCH _2- or CH _2- , and R ⁴ Is a linear or branched alkyl group having 1 to 22 carbon atoms, a linear or branched alkoxyl group having 1 to 22 carbon atoms, a linear or branched alkyl group having 1 to 22 carbon atoms, or a fluorine-containing alkyl group. It is a fluorine-containing alkoxyl group.
R ⁵ is -COO-, -OCO-, -CONH-, -NHCO-, -COOCH _2- , -CH ₂ OCO-, -CH ₂ O-, -OCH _2- , -CH _2- , -O- Alternatively, it indicates NH-, and R ⁶ is a fluorine group, a cyano group, a trifluoromethane group, a nitro group, an azo group, a formyl group, an acetyl group, an acetoxy group or a hydroxyl group.
R ⁷ is a linear or branched alkyl group having 3 to 12 carbon atoms, and the cis-trans isomers of 1,4-cyclohexylene are trans isomers, respectively.
R ⁸ is a linear or branched alkyl group having 3 to 12 carbon atoms, and the cis-trans isomers of 1,4-cyclohexylene are trans isomers, respectively.
A ₄ is a linear or branched alkyl group having 3 to 20 carbon atoms which may be substituted with a fluorine atom, and A ₃ is a 1,4-cyclohexylene group or a 1,4-phenylene group. A ₂ is an oxygen atom or COO- * (however, a bond with "*" binds to A ₃ ), and A ₁ is an oxygen atom or COO- * (however, a bond with "*"). Is combined with (CH ₂ ) a ₂ )). Further, a ₁ is an integer of 0 or 1, a ₂ is an integer of ₂ to 10, and a ₃ is an integer of 0 or 1.

Of the above formulas [2a-1] to [2a-31], particularly preferable are formulas [2a-1] to [2a-6], formulas [2a-9] to [2a-13], or formulas [2a-13]. 2a-22] to the formula [2a-31].

Further, examples of the diamine having a specific side chain structure represented by the formula [II-2] include diamines represented by the following formulas [2b-1] to [2b-10].
A ¹ represents an alkyl group having 1 to 22 carbon atoms or a fluorine-containing alkyl group.

In the above formulas [2b-5] to [2b-10], A ¹ is -COO-, -OCO-, -CONH-, -NHCO-, -CH _2- , -O-, -CO- or NH-. ² indicates a linear or branched alkyl group having 1 to 22 carbon atoms or a linear or branched fluorine-containing alkyl group having 1 to 22 carbon atoms.
The above diamine may be used alone or in combination of two or more depending on the characteristics such as the liquid crystal orientation, the pretilt angle, the voltage holding characteristic, and the accumulated charge when the liquid crystal alignment film is formed.

The diamine having a side chain for vertically orienting the liquid crystal is preferably 5 to 50 mol% of the diamine component used for the synthesis of the polyamic acid, more preferably 10 to 40 mol% of the diamine component, and particularly preferably. Is 15-30 mol%.
The use of a diamine having a side chain that orients the liquid crystal vertically is particularly excellent in terms of improving the response speed and the ability to fix the orientation of the liquid crystal.

<Diamine containing photoreactive side chains>
The diamine having a photoreactive side chain is, for example, a diamine having a side chain represented by the formula [3], and specifically, R in the following general formula [3] (formula [3]). The definitions of ⁸ , R ⁹ and R ¹⁰ are the same as those in the above formula [III]), but the diamine is not limited thereto.

The bonding position of the two amino groups (-NH ₂ ) in the formula [3] is not limited. Specifically, the positions 2, 3 and 2, 4 and 2, 5 and 2, 6 and 3, 4 and 3, 4 positions on the benzene ring with respect to the bonding group of the side chain. The position of 5 is mentioned. Of these, the 2,4 position, the 2,5 position, or the 3,5 position is preferable from the viewpoint of reactivity in synthesizing the polyamic acid. Considering the ease of synthesizing the diamine, the positions 2, 4 or 3, 5 are more preferable.
Specific examples of the diamine having a photoreactive side chain include the following.
In the formula, X ⁹ and X ¹⁰ are independent bonding groups that are single bonds, -O-, -COO-, -NHCO-, or -NH-, and Y is a carbon that may be substituted with a fluorine atom. Represents the number 1 to 20 of alkylene groups.

Examples of the diamine having a photoreactive side chain include a diamine having a group that causes a photodimerization reaction represented by the following formula and a group that causes a photopolymerization reaction in the side chain.

In the above formula, Y ₁ represents -CH _2- , -O-, -CONH-, -NHCO-, -COO-, -OCO-, -NH-, or -CO-. Y ₂ is an alkylene group having 1 to 30 carbon atoms, a divalent carbon ring or a heterocycle, and one or more hydrogen atoms of the alkylene group, the divalent carbon ring or the heterocycle are fluorine atoms or organic. It may be substituted with a group. In Y ₂ , -CH _2- may be substituted with these groups if the following groups are not adjacent to each other; -O-, -NHCO-, -CONH-, -COO-, -OCO-, -NH-, -NHCONH-, -CO-. Y ₃ represents -CH _2- , -O-, -CONH-, -NHCO-, -COO-, -OCO-, -NH-, -CO-, or a single bond. Y ₄ represents a cinnamoyl group. Y ₅ is a single bond, an alkylene group having 1 to 30 carbon atoms, a divalent carbon ring or a heterocycle, and one or more hydrogen atoms of the alkylene group, the divalent carbon ring or the heterocycle are fluorine atoms. Alternatively, it may be substituted with an organic group. Y _5, when the next group is not adjacent to each other, -CH ₂ - may be substituted with these groups; -O -, - NHCO -, - CONH -, - COO -, - OCO-, -NH-, -NHCONH-, -CO-. Y ₆ represents a photopolymerizable group which is an acrylic group or a methacrylic group.

The diamine having a photoreactive side chain depends on the liquid crystal orientation when used as a liquid crystal alignment film, pretilt angle, voltage holding characteristics, characteristics such as accumulated charge, and the response speed of the liquid crystal when used as a liquid crystal display element. Therefore, one type or a mixture of two or more types can be used.
Further, as the diamine having a photoreactive side chain, it is preferable to use 10 to 70 mol% of the diamine component used for the synthesis of polyamic acid, more preferably 20 to 60 mol%, and particularly preferably 30 to 50 mol%. Is.

<Other diamines>
In addition, when producing a polyimide precursor and / or polyimide, a diamine other than the above-mentioned diamine can be used in combination as a diamine component as long as the effect of the present invention is not impaired. Specifically, for example, p-phenylenediamine, 2,3,5,6-tetramethyl-p-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, m-phenylenediamine, 2,4-dimethyl- m-phenylenediamine, 2,5-diaminotoluene, 2,6-diaminotoluene, 2,5-diaminophenol, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2, 4-Diaminobenzyl alcohol, 4,6-diaminoresorcinol, 4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl , 3,3'-dihydroxy-4,4'-diaminobiphenyl, 3,3'-dicarboxy-4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'-biphenyl, 3,3'-Trifluoromethyl-4,4'-diaminobiphenyl,3,4'-diaminobiphenyl,3,3'-diaminobiphenyl,2,2'-diaminobiphenyl,2,3'-diaminobiphenyl,4,4'- Diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 2,2'-diaminodiphenylmethane, 2,3'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether , 3,4'-diaminodiphenyl ether, 2,2'-diaminodiphenyl ether, 2,3'-diaminodiphenyl ether, 4,4'-sulfonyldianiline, 3,3'-sulfonyldianiline, bis (4-aminophenyl) Silane, bis (3-aminophenyl) silane, dimethyl-bis (4-aminophenyl) silane, dimethyl-bis (3-aminophenyl) silane, 4,4'-thiodianiline, 3,3'-thiodianiline, 4,4 ′ -Diaminodiphenylamine, 3,3′-diaminodiphenylamine, 3,4′-diaminodiphenylamine, 2,2′-diaminodiphenylamine, 2,3′-diaminodiphenylamine, N-methyl (4,4′-diaminodiphenyl) amine , N-methyl (3,3'-diaminodiphenyl) amine, N-methyl (3,4'-diaminodiphenyl) amine, N-methyl (2,2'-diaminodiphenyl) amine, N-methyl (2,3) '-Diaminodiphenyl) amine, 4,4'-diamino Benzenephenone, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 1,4-diaminonaphthalene, 2,2'-diaminobenzophenone, 2,3'-diaminobenzophenone, 1,5-diaminonaphthalene, 1, 6-Diaminonaphthalene, 1,7-diaminonaphthalene, 1,8-diaminonaphthalene, 2,5-diaminonaphthalene, 2,6 diaminonaphthalene, 2,7-diaminonaphthalene, 2,8-diaminonaphthalene, 1,2- Bis (4-aminophenyl) ethane, 1,2-bis (3-aminophenyl) ethane, 1,3-bis (4-aminophenyl) propane, 1,3-bis (3-aminophenyl) propane, 1, 4-bis (4-aminophenyl) butane, 1,4-bis (3-aminophenyl) butane, bis (3,5-diethyl-4-aminophenyl) methane, 1,4-bis (4-aminophenoxy) Benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenyl) benzene, 1,3-bis (4-aminophenyl) benzene, 1,4-bis (4-amino) Benzene) Benzene, 1,3-bis (4-aminophenoxy) benzene, 4,4'-[1,4-phenylenebis (methylene)] dianiline, 4,4'-[1,3-phenylenebis (methylene)) ] Dianiline, 3,4'-[1,4-phenylenebis (methylene)] dianiline, 3,4'-[1,3-phenylenebis (methylene)] dianiline, 3,3'-[1,4-phenylene Bis (methylene)] dianiline, 3,3'-[1,3-phenylenebis (methylene)] dianiline, 1,4-phenylenebis [(4-aminophenyl) metanone], 1,4-phenylenebis [(3) -Aminophenyl) methanone], 1,3-phenylenebis [(4-aminophenyl) methanone], 1,3-phenylenebis [(3-aminophenyl) methanone], 1,4-phenylenebis (4-aminobenzoate) ), 1,4-Phenylenebis (3-aminobenzoate), 1,3-phenylenebis (4-aminobenzoate), 1,3-phenylenebis (3-aminobenzoate), bis (4-aminophenyl) terephthalate, Bis (3-aminophenyl) terephthalate, bis (4-aminophenyl) isophthalate, bis (3-aminophenyl) isophthalate, N, N'-(1,4-phenylene) bis (4-aminobenzamide) ), N, N'-(1,3-phenylene) bis (4-aminobenzamide), N, N'-(1,4-phenylene) bis (3-aminobenzamide), N, N'-(1, 3-Phenyl) bis (3-aminobenzamide), N, N'-bis (4-aminophenyl) terephthalamide, N, N'-bis (3-aminophenyl) terephthalamide, N, N'-bis (4) -Aminophenyl) isophthalamide, N, N'-bis (3-aminophenyl) isophthalamide, 9,10-bis (4-aminophenyl) anthracene, 4,4'-bis (4-aminophenoxy) diphenylsulfone, 2,2'-bis [4- (4-aminophenoxy) phenyl] propane, 2,2'-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2'-bis (4-amino) Phenyl) hexafluoropropane, 2,2'-bis (3-aminophenyl) hexafluoropropane, 2,2'-bis (3-amino-4-methylphenyl) hexafluoropropane, 2,2'-bis (4) -Aminophenyl) propane, 2,2'-bis (3-aminophenyl) propane, 2,2'-bis (3-amino-4-methylphenyl) propane, 3,5-diaminobenzoic acid, 2,5- Diaminobenzoic acid, 1,3-bis (4-aminophenoxy) propane, 1,3-bis (3-aminophenoxy) propane, 1,4-bis (4-aminophenoxy) butane, 1,4-bis (3) -Aminophenoxy) butane, 1,5-bis (4-aminophenoxy) pentane, 1,5-bis (3-aminophenoxy) pentane, 1,6-bis (4-aminophenoxy) hexane, 1,6- Bis (3-aminophenoxy) hexane, 1,7-bis (4-aminophenoxy) heptane, 1,7- (3-aminophenoxy) heptane, 1,8-bis (4-aminophenoxy) octane, 1, 8-bis (3-aminophenoxy) octane, 1,9-bis (4-aminophenoxy) nonane, 1,9-bis (3-aminophenoxy) nonan, 1,10- (4-aminophenoxy) decane, 1 , 10- (3-Aminophenoxy) Decane, 1,11- (4-Aminophenoxy) Undecane, 1,11- (3-Aminophenoxy) Undecane, 1,12- (4-Aminophenoxy) Dodecane, 1,12 -Aromatic diamines such as (3-aminophenoxy) dodecane, bis (4-aminocyclohexy) To alicyclic diamines such as methane and bis (4-amino-3-methylcyclohexyl) methane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, and 1,6-diamino. Aliphatic diamines such as xan, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, and 1,12-diaminododecane can be mentioned. ..

The other diamines may be used alone or in combination of two or more depending on the characteristics such as the liquid crystal orientation, the pretilt angle, the voltage holding characteristic, and the accumulated charge when the liquid crystal alignment film is formed.

<Tetracarboxylic dianhydride>
The tetracarboxylic dianhydride component to be reacted with the above diamine component is not particularly limited. Specifically, pyromellitic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 1,2,5,6-naphthalenetetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid, 2, 3,6,7-anthracene tetracarboxylic acid, 1,2,5,6-anthracene tetracarboxylic acid, 3,3', 4,4'-biphenyltetracarboxylic acid, 2,3,3', 4-biphenyltetra Carboxylic acid, bis (3,4-dicarboxyphenyl) ether, 3,3', 4,4'-benzophenone tetracarboxylic acid, bis (3,4-dicarboxyphenyl) sulfone, bis (3,4-dicarboxyphenyl) Phenyl) methane, 2,2-bis (3,4-dicarboxyphenyl) propane, 1,1,1,3,3,3-hexafluoro-2,2-bis (3,4-dicarboxyphenyl) propane , Bis (3,4-dicarboxyphenyl) dimethylsilane, bis (3,4-dicarboxyphenyl) diphenylsilane, 2,3,4,5-pyridinetetracarboxylic acid, 2,6-bis (3,4-bis) Dicarboxyphenyl) pyridine, 3,3', 4,4'-diphenylsulfonetetracarboxylic acid, 3,4,9,10-perylenetetracarboxylic acid, 1,3-diphenyl-1,2,3,4-cyclobutane Tetracarboxylic acid, oxydiphthaltetracarboxylic acid, 1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,3,4-cyclopentanetetracarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid , 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic acid, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid, 1,3-dimethyl- 1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,3,4-cycloheptanetetracarboxylic acid, 2,3,4,5-tetracarboxylic acid, 3,4-dicarboxy-1-cyclo Hexylsuccinic acid, 2,3,5-tricarboxycyclopentylacetic acid, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalensuccinic acid, bicyclo [3,3,0] octane-2, 4,6,8-tetracarboxylic acid, bicyclo [4,3,0] nonane-2,4,7,9-tetracarboxylic acid, bicyclo [4,4,0] decan-2,4,7,9- Tetracarboxylic acid, bicyclo [4,4,0] decan-2,4,8,10-tetracarboxylic acid, tricyclo [6.3.0.0 <2,6>] c Ndecane-3,5,9,11-tetracarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, 4- (2,5-dioxo tetrahydrofuran-3-yl) -1,2,3,4 -Tetrahydrinaphthalene-1,2-dicarboxylic acid, bicyclo [2,2,2] octo-7-ene-2,3,5,6-tetracarboxylic acid, 5- (2,5-dioxotetrahydrofuryl) -3-Methyl-3-cyclohexane-1,2-dicarboxylic acid, tetracyclo [6,2,1,1,0,2,7] dodeca-4,5,9,10-tetracarboxylic acid, 3, Examples thereof include 5,6-tricarboxynorbornane-2: 3,5: 6 dicarboxylic acid and 1,2,4,5-cyclohexanetetracarboxylic acid. Of course, one or two or more types of tetracarboxylic dianhydride may be used in combination depending on the characteristics such as liquid crystal orientation, voltage holding characteristics, and accumulated charge when the liquid crystal alignment film is formed.

<Polymerizable compound>
The liquid crystal alignment agent of the present invention may contain a polymerizable compound having two or more terminals having a photopolymerizable or photocrosslinking group, if necessary. Such a polymerizable compound is a compound having two or more terminals having a group that photopolymerizes or photocrosslinks. Here, the polymerizable compound having a photopolymerizable group is a compound having a functional group that causes polymerization by irradiating with light. Further, the compound having a photocrosslinking group is at least one selected from a polymer of a polymerizable compound, a polyimide precursor, and a polyimide obtained by imidizing the polyimide precursor by irradiation with light. It is a compound having a functional group that can react with the polymers of the above and crosslink with them. The compound having a photocrosslinking group also reacts with the compound having a photocrosslinking group.

By using the liquid crystal aligning agent of the present invention containing the above-mentioned polymerizable compound in a vertically oriented liquid crystal display element such as an SC-PVA type liquid crystal display, the side chain for vertically aligning the liquid crystal and the photoreactive property can be obtained. The response rate can be remarkably improved as compared with the case where a polymer having a side chain or this polymerizable compound is used alone, and the response rate can be sufficiently improved even with a small amount of the polymerizable compound added. Can be done.
Examples of the group to be photopolymerized or photocrosslinked include a monovalent group represented by the following formula (IV).
In the formula, R ¹² represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Z ¹ represents a divalent aromatic ring or heterocycle which may be substituted with an alkyl group having 1 to 12 carbon atoms or an alkoxyl group having 1 to 12 carbon atoms. Z ² represents a monovalent aromatic ring or heterocycle which may be substituted with an alkyl group having 1 to 12 carbon atoms or an alkoxyl group having 1 to 12 carbon atoms.

Specific examples of the polymerizable compound include a compound having a photopolymerizable group at each of the two terminals represented by the following formula (V), a terminal having a photopolymerizable group represented by the following formula (VI), and light. Examples thereof include a compound having a terminal having a cross-linking group and a compound having a group having a photo-cross-linking group at each of the two terminals represented by the following formula (VII).
In Formula ^{(V) ~ (VII),} R 12, Z 1 and ^{Z 2} are the same as ^R 12, ^{Z 1} and ^{Z 2} in the formula (IV), ^{Q 1} is a divalent organic group is there. Q ¹ represents a phenylene group _{(-C 6 H} 4 -), biphenylene group _{(-C 6 H 4 -C 6 H} 4 -), cyclohexylene _{(-C 6 H 10} -) having a cyclic structure, such as It is preferable to have. This is because the interaction with the liquid crystal tends to increase.

Specific examples of the polymerizable compound represented by the formula (V) include the polymerizable compound represented by the following formula (R-1). In the following formula (R-1), V and W are represented by a single bond or −R ¹ O−, and R ¹ is a linear or branched alkylene group having 1 to 10 carbon atoms, preferably. , -R ¹ O-, and R ¹ is a linear or branched alkylene group having 2 to 6 carbon atoms. Note that V and W may be the same or different, but if they are the same, synthesis is easy.

Even if the photopolymerizable or photocrosslinking group is a polymerizable compound having an acrylate group or a methacrylate group instead of an α-methylene-γ-butyrolactone group, the acrylate group or methacrylate group is a spacer such as an oxyalkylene group. The polymerizable compound having a structure bonded to the phenylene group via the above can significantly improve the response rate in the same manner as the polymerizable compound having an α-methylene-γ-butyrolactone group at both ends. .. Further, a polymerizable compound having a structure in which an acrylate group or a methacrylate group is bonded to a phenylene group via a spacer such as an oxyalkylene group has improved stability against heat and has a high temperature, for example, a firing temperature of 200 ° C. or higher. Can withstand enough.

The method for producing the above-mentioned polymerizable compound is not particularly limited, and for example, it can be produced according to the following synthesis example. For example, as the polymerizable compound represented by the above formula (R-1), Taraga and the like represented by the following reaction formula are proposed by P. Talaga, M. Schaeffer, C. Benezra and JLStampf, Synthesis, 530 (1990). 2- (Bromomethyl) acrylic acid (2- (bromomethyl) propenoic acid) can be reacted with an aldehyde or a ketone using SnCl ₂ to synthesize the compound. Amberlyst 15 is a strongly acidic ion exchange resin manufactured by Rohm and Haas.
In the following formula, R'represents a monovalent organic group.

As for 2- (bromomethyl) acrylic acid, Lamaran and the like represented by the following reaction formula are described in K. Ramarajan, K. Kamalingam, DJO'Donnell and KDBerlin, Organic Synthesis, vol.61, 56-59 (1983). It can be synthesized by the proposed method.

As a specific example of synthesis, when synthesizing a polymerizable compound represented by the above formula (R-1) in which V is −R ¹ O−, W is −OR ²⁻ and R ¹ and R ² are the same, , Two methods represented by the following reaction formulas can be mentioned.

Further, when synthesizing a polymerizable compound represented by the above formula (R-1) in which R ¹ and R ² are different, a method represented by the following reaction formula can be mentioned.

In the above formula (R-1), when synthesizing a polymerizable compound in which V and W are single bonds, the method represented by the following reaction formula can be mentioned.

<Synthesis of polyamic acid>
A known synthetic method can be used to obtain a polyamic acid by reacting the diamine component with the tetracarboxylic dianhydride. Generally, it is a method of reacting a diamine component and a tetracarboxylic dianhydride component in an organic solvent. The reaction of the diamine component with the tetracarboxylic dianhydride is advantageous in that it proceeds relatively easily in an organic solvent and no by-products are generated.

The organic solvent used in the above reaction is not particularly limited as long as it dissolves the produced polyamic acid. Further, even if the organic solvent does not dissolve the polyamic acid, it may be mixed with the above solvent and used as long as the produced polyamic acid does not precipitate. Since the water content in the organic solvent inhibits the polymerization reaction and further causes the produced polyamic acid to be hydrolyzed, it is preferable to use a dehydrated and dried organic solvent.

Examples of the organic solvent used in the above reaction include N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylformamide, N-methylformamide, N-methyl-2-pyrrolidone, and N-ethyl-2. -Pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, 3-methoxy-N, N-dimethylpropanamide, N-methylcaprolactam, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethyl Sulfoxide, γ-butyrolactone, isopropyl alcohol, methoxymethylpentanol, dipentene, ethylamyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, methyl cell solve, ethyl cell solution, methyl cellosolve acetate, butyl cellosolve acetate, ethyl Cellosolve acetate, butyl carbitol, ethyl carbitol, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol -Tert-Butyl ether, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether , Dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol , Diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, dioxane, n-hexane, n-pentane, n-octa Diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, 3-methoxypropionic acid Methyl, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, diglime, 4-hydroxy-4 -Methyl-2-pentanone, 2-ethyl-1-hexanol and the like can be mentioned. These organic solvents may be used alone or in combination.

In the method of reacting the diamine component and the tetracarboxylic dianhydride component in an organic solvent, a solution in which the diamine component is dispersed or dissolved in an organic solvent is stirred, and the tetracarboxylic dianhydride component is used as it is or in an organic solvent. A method of dispersing or dissolving the tetracarboxylic dianhydride component in a solution or adding the diamine component to a solution in which the tetracarboxylic dianhydride component is dispersed or dissolved in an organic solvent, and alternating between the tetracarboxylic dianhydride component and the diamine component. It may be added to any of the methods. When the diamine component or the tetracarboxylic dianhydride component is composed of a plurality of types of compounds, they may be reacted in a premixed state, may be reacted individually in sequence, or may be reacted individually and have a low molecular weight. The bodies may be mixed and reacted to form a high molecular weight compound.

The temperature at which the diamine component and the tetracarboxylic dianhydride component are reacted is, for example, in the range of −20 ° C. to 150 ° C., preferably −5 ° C. to 100 ° C. Further, in the reaction, for example, the total concentration of the diamine component and the tetracarboxylic dianhydride component is preferably 1 to 50% by mass, more preferably 5 to 30% by mass with respect to the reaction solution.
The ratio of the total number of moles of the tetracarboxylic dianhydride component to the total number of moles of the diamine component in the above polymerization reaction can be selected according to the molecular weight of the polyamic acid to be obtained. Similar to a normal polycondensation reaction, the closer the molar ratio is to 1.0, the larger the molecular weight of the polyamic acid produced, which is 0.8 to 1.2 if a preferable range is shown.

The method for synthesizing the polyamic acid used in the present invention is not limited to the above method, and as in the general method for synthesizing a polyamic acid, instead of the above tetracarboxylic dianhydride, a tetracarboxylic having a corresponding structure is used. The corresponding polyamic acid can also be obtained by reacting with an acid or a tetracarboxylic acid derivative such as a tetracarboxylic acid dihalide by a known method.
Examples of the method for imidizing the above-mentioned polyamic acid to obtain polyimide include thermal imidization in which the polyamic acid solution is heated as it is, and catalytic imidization in which a catalyst is added to the polyamic acid solution. The imidization ratio from polyamic acid to polyimide does not necessarily have to be 100%.

The temperature at which the polyamic acid is thermally imidized in the solution is 100 ° C. to 400 ° C., preferably 120 ° C. to 250 ° C., and it is preferable to remove the water generated by the imidization reaction from the system.
Catalytic imidization of polyamic acid can be carried out by adding a basic catalyst and an acid anhydride to a solution of polyamic acid and stirring at -20 to 250 ° C., preferably 0 to 180 ° C. The amount of the basic catalyst is 0.5 to 30 mol times, preferably 2 to 20 mol times, that of the amic acid group, and the amount of acid anhydride is 1 to 50 mol times, preferably 3 to 30 mol times that of the amic acid group. It is double. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, pyridine is preferable because it has an appropriate basicity for advancing the reaction. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, pyromellitic anhydride and the like. Among them, acetic anhydride is preferable because it facilitates purification after completion of the reaction. The imidization rate by catalytic imidization can be controlled by adjusting the amount of catalyst, the reaction temperature, and the reaction time.

Further, the polyamic acid ester is a reaction of the tetracarboxylic acid diester dichloride with a diamine similar to the synthesis of the polyamic acid, or a condensing agent suitable for the tetracarboxylic acid diester and the diamine similar to the synthesis of the polyamic acid. It can be produced by reacting in the presence of a base or the like. It can also be obtained by synthesizing a polyamic acid in advance by the above method and esterifying the carboxylic acid in the amic acid by utilizing a polymer reaction. Specifically, for example, tetracarboxylic dianester dichloride and diamine are mixed in the presence of a base and an organic solvent at −20 ° C. to 150 ° C., preferably 0 ° C. to 50 ° C. for 30 minutes to 24 hours, preferably 1 hour. A polyamic acid ester can be synthesized by reacting for ~ 4 hours. Polyimide can also be obtained by heating the polyamic acid ester at a high temperature to promote dealcoholization and ring closure.

When recovering the produced polyimide precursor such as polyamic acid or polyamic acid ester or polyimide from the reaction solution, the reaction solution may be poured into a poor solvent for precipitation. Examples of the poor solvent used for precipitation include methanol, acetone, hexane, butyl cellsolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, water and the like. The polymer which has been put into a poor solvent and precipitated can be collected by filtration and then dried at normal temperature or by heating under normal pressure or reduced pressure. Further, by repeating the operation of redistributing the recovered polymer in an organic solvent and reprecipitating and recovering it 2 to 10 times, impurities in the polymer can be reduced. Examples of the poor solvent at this time include alcohols, ketones, hydrocarbons, and the like, and it is preferable to use three or more kinds of poor solvents selected from these, because the purification efficiency is further improved.

<Liquid crystal alignment agent>
The liquid crystal alignment agent of the present invention contains the above-mentioned polyimide precursor, and the content of the polyimide precursor is preferably 1 to 20% by mass, more preferably 3 to 15% by mass, and particularly preferably 3 to 10% by mass. Is. When a polymerizable compound having two or more terminals having a photopolymerizable or photocrosslinking group is contained, the content thereof is preferably 1 to 50 parts by mass with respect to 100 parts by mass of the polymer. It is preferably 5 to 30 parts by mass.

Further, the liquid crystal alignment agent of the present invention may contain a polymer other than the above-mentioned polyimide precursor. At that time, the content of the other polymer in all the components of the polymer is preferably 0.5 to 80% by mass, more preferably 20 to 50% by mass.
The molecular weight of the polymer contained in the liquid crystal alignment agent is GPC (Gel Permeation Chromatography) in consideration of the strength of the liquid crystal alignment film obtained by applying the liquid crystal alignment agent, the workability at the time of forming the coating film, and the uniformity of the coating film. ), The weight average molecular weight measured by the method is preferably 5,000 to 1,000,000, more preferably 10,000 to 150,000.

The solvent contained in the liquid crystal aligning agent is not particularly limited, and the above-mentioned polyimide precursor and, if necessary, a polymerizable compound having two or more terminal photopolymerizable or photocrosslinking groups, etc. Any substance may be used as long as it can dissolve or disperse the contained components. For example, an organic solvent as exemplified in the above synthesis of polyamic acid can be mentioned. Among them, N-methyl-2-pyrrolidone, γ-butyrolactone, N-ethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, 3-methoxy-N, and N-dimethylpropanamide are soluble. Is preferable. Of course, two or more kinds of mixed solvents may be used.

Further, it is preferable to use a solvent that improves the uniformity and smoothness of the coating film by mixing it with a solvent having high solubility of the components contained in the liquid crystal alignment agent. Examples of such a solvent include isopropyl alcohol, methoxymethylpentanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl cellosolve acetate, butyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethyl carbitol acetate, ethylene glycol, and the like. Ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol Monoacetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol mono Propyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, Butylbutyrate, butyl ether, diisobutylketone, methylcyclohexene, propyl ether, dihexyl ether, n-hexane, n-pentane, n-octane, diethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-acetate Butyl, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid , Propyl 3-methoxypropionate, butyl 3-methoxypropionate, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol , Propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, 2- (2-ethoxypropoxy) propanol , Lactic acid methyl ester, lactate ethyl ester, lactate n-propyl ester, lactate n-butyl ester, lactate isoamyl ester, 2-ethyl-1-hexanol and the like. A plurality of types of these solvents may be mixed. These solvents are preferably 5 to 80% by mass, more preferably 20 to 60% by mass, based on the total amount of the solvent contained in the liquid crystal alignment agent.

The liquid crystal alignment agent may contain components other than the above. Examples thereof include a compound that improves the film thickness uniformity and surface smoothness when the liquid crystal alignment agent is applied, a compound that improves the adhesion between the liquid crystal alignment film and the substrate, and the like.
Examples of compounds that improve the uniformity of film thickness and surface smoothness include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants. More specifically, for example, Ftop EF301, EF303, EF352 (manufactured by Tochem Products), Megafuck F171, F173, R-30 (manufactured by Dainippon Ink Co., Ltd.), Florard FC430, FC431 (manufactured by Sumitomo 3M Ltd.) , Asahi Guard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (manufactured by Asahi Glass Co., Ltd.) and the like. The ratio of these surfactants used is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass, based on 100 parts by mass of the total amount of the polymer contained in the liquid crystal alignment agent. ..

Specific examples of the compound that improves the adhesion between the liquid crystal alignment film and the substrate include a functional silane-containing compound and an epoxy group-containing compound. For example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane. , N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxy Carbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-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-aminopropyltrimethoxy Silane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neo Pentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol , N, N, N', N'-tetraglycidyl-m-xylene diamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N', N'-tetraglycidyl-4 , 4'-Diaminodiphenylmethane, 3- (N-allyl-N-glycidyl) aminopropyltrimethoxysilane, 3- (N, N-diglycidyl) aminopropyltrimethoxysilane and the like.

Further, a phenol compound such as 2,2'-bis (4-hydroxy-3,5-dihydroxymethylphenyl) propane or tetra (methoxymethyl) bisphenol may be added in order to further increase the film strength of the liquid crystal alignment film. .. These compounds are preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, based on 100 parts by mass of the total amount of the polymer contained in the liquid crystal alignment agent.
Further, in addition to the above, a dielectric or a conductive substance for changing the electrical characteristics such as the dielectric constant and conductivity of the liquid crystal alignment film is added to the liquid crystal alignment agent as long as the effect of the present invention is not impaired. You may.

By applying this liquid crystal alignment agent on a substrate and firing it, a liquid crystal alignment film that vertically orients the liquid crystal can be formed. By using the liquid crystal alignment agent of the present invention, the response speed of the liquid crystal display element using the obtained liquid crystal alignment film can be increased. Further, the polymerizable compound having two or more terminals that are photopolymerized or photocrosslinked, which may be contained in the liquid crystal alignment agent of the present invention, is not contained in the liquid crystal alignment agent or is contained in the liquid crystal alignment agent. At the same time, by containing it in the liquid crystal, the photoreaction becomes highly sensitive even in the so-called PSA mode, and the tilt angle can be imparted even with a small amount of ultraviolet light irradiation.

For example, a cured film obtained by applying the liquid crystal alignment agent of the present invention to a substrate, drying it if necessary, and firing it can be used as it is as a liquid crystal alignment film. Further, a state in which the cured film is rubbed, polarized light or light of a specific wavelength is irradiated, an ion beam or the like is processed, or a voltage is applied to the liquid crystal display element after filling the liquid crystal as a PSA alignment film. It is also possible to irradiate with UV. In particular, it is useful to use it as an alignment film for PSA.

At this time, the substrate to be used is not particularly limited as long as it is a highly transparent substrate, and is a glass plate, polycarbonate, poly (meth) acrylate, polyether sulphon, polyarylate, polyurethane, polysalphon, polyether, polyetherketone. , Trimethylpentene, polyolefin, polyethylene terephthalate, (meth) acrylonitrile, triacetyl cellulose, diacetyl cellulose, acetate butylate cellulose and other plastic substrates can be used. Further, it is preferable to use a substrate on which an ITO electrode or the like for driving a liquid crystal is formed from the viewpoint of simplifying the process. Further, in the reflective liquid crystal display element, an opaque object such as a silicon wafer can be used if only one side of the substrate is used, and in this case, a material that reflects light such as aluminum can also be used as the electrode.

The method for applying the liquid crystal alignment agent is not particularly limited, and examples thereof include printing methods such as screen printing, offset printing, flexographic printing, inkjet method, spray method, roll coating method, dip, roll coater, slit coater, spinner and the like. From the viewpoint of productivity, the transfer printing method is widely used industrially, and is preferably used in the present invention.
The coating film formed by applying the liquid crystal alignment agent by the above method can be fired to form a cured film. The drying step after applying the liquid crystal alignment agent is not always necessary, but if the time from coating to firing is not constant for each substrate, or if firing is not performed immediately after coating, a drying step is performed. Is preferable. The drying is not particularly limited as long as the solvent is removed to the extent that the shape of the coating film is not deformed by the transportation of the substrate or the like. For example, a method of drying on a hot plate having a temperature of 40 ° C. to 150 ° C., preferably 60 ° C. to 100 ° C. for 0.5 minutes to 30 minutes, preferably 1 minute to 5 minutes can be mentioned.

The firing temperature of the coating film formed by applying the liquid crystal alignment agent is not limited, and is, for example, 100 to 350 ° C., preferably 120 to 300 ° C., and more preferably 150 ° C. to 250 ° C. The firing time is 5 minutes to 240 minutes, preferably 10 minutes to 90 minutes, and more preferably 20 minutes to 90 minutes. The heating can be performed by a generally known method, for example, a hot plate, a hot air circulation furnace, an infrared furnace, or the like.
The thickness of the liquid crystal alignment film obtained by firing is not particularly limited, but is preferably 5 to 300 nm, more preferably 10 to 100 nm.

<Liquid crystal display element>
In the liquid crystal display element of the present invention, a liquid crystal cell can be produced by a known method after forming a liquid crystal alignment film on a substrate by the above method. As a specific example of the liquid crystal display element, two substrates arranged so as to face each other, a liquid crystal layer provided between the substrates, and formed by the liquid crystal alignment agent of the present invention provided between the substrates and the liquid crystal layer. It is a vertical alignment type liquid crystal display element including a liquid crystal cell having the above liquid crystal alignment film. Specifically, the liquid crystal alignment agent of the present invention is applied onto two substrates and fired to form a liquid crystal alignment film, and the two substrates are arranged so that the liquid crystal alignment films face each other. By sandwiching a liquid crystal layer composed of liquid crystal between two substrates, that is, providing the liquid crystal layer in contact with the liquid crystal alignment film and irradiating the liquid crystal alignment film and the liquid crystal layer with ultraviolet rays while applying a voltage. It is a vertically oriented liquid crystal display element including a liquid crystal cell to be manufactured.

Using the liquid crystal alignment film formed by the liquid crystal alignment agent of the present invention, the polymerizable compound is polymerized by irradiating the liquid crystal alignment film and the liquid crystal layer with ultraviolet rays while applying a voltage, and the photoreactivity of the polymer is exhibited. By reacting the side chains with each other or the photoreactive side chains of the polymer with the polymerizable compound, the orientation of the liquid crystal is more efficiently fixed, and the liquid crystal display element having a remarkably excellent response speed is obtained.

The substrate used for the liquid crystal display element of the present invention is not particularly limited as long as it is a highly transparent substrate, but is usually a substrate on which a transparent electrode for driving a liquid crystal is formed. As a specific example, the same substrate as that described in the liquid crystal alignment film can be mentioned. A substrate provided with a conventional electrode pattern or protrusion pattern may be used, but since the liquid crystal aligning agent of the present invention is used in the liquid crystal display element of the present invention, for example, a line of 1 to 10 μm is used on one side of the substrate. / It is possible to operate even in a structure in which a slit electrode pattern is formed and no slit pattern or protrusion pattern is formed on the facing substrate. The liquid crystal display element having this structure simplifies the manufacturing process and has high transmittance. Can be obtained.

Further, in a high-performance element such as a TFT type element, an element having an element such as a transistor formed between an electrode for driving a liquid crystal and a substrate is used.
In the case of a transmissive liquid crystal display element, it is common to use a substrate as described above, but in a reflective liquid crystal display element, an opaque substrate such as a silicon wafer may be used if only one side of the substrate is used. It is possible. At that time, a material such as aluminum that reflects light can be used for the electrodes formed on the substrate.

The liquid crystal material constituting the liquid crystal layer of the liquid crystal display element of the present invention is not particularly limited, and the liquid crystal material used in the conventional vertical orientation method, for example, a negative type such as MLC-6608 or MLC-6609 manufactured by Merck Co., Ltd. A liquid crystal can be used. Further, in the PSA mode, for example, a liquid crystal containing a polymerizable compound as represented by the following formula can be used.

In the present invention, as a method of sandwiching the liquid crystal layer between two substrates, a known method can be mentioned. For example, a pair of substrates on which a liquid crystal alignment film is formed is prepared, and spacers such as beads are sprayed on the liquid crystal alignment film of one substrate so that the surface on the side on which the liquid crystal alignment film is formed is on the inside. Another method is to bond the other substrate and inject the liquid crystal under reduced pressure to seal it. Further, a pair of substrates on which the liquid crystal alignment film is formed is prepared, spacers such as beads are sprayed on the liquid crystal alignment film of one substrate, liquid crystal is dropped, and then the surface on the side where the liquid crystal alignment film is formed. A liquid crystal cell can also be produced by a method in which the other substrate is bonded and sealed so that the surface is on the inside. The thickness of the spacer is preferably 1 to 30 μm, more preferably 2 to 10 μm.

In the process of producing a liquid crystal cell by irradiating the liquid crystal alignment film and the liquid crystal layer with ultraviolet rays while applying a voltage, for example, an electric field is applied to the liquid crystal alignment film and the liquid crystal layer by applying a voltage between electrodes installed on the substrate. Is applied, and an ultraviolet ray is irradiated while maintaining this electric field. Here, the voltage applied between the electrodes is, for example, 5 to 30 Vp-p, preferably 5 to 20 Vp-p. The irradiation amount of ultraviolet rays is, for example, 1 to 60 J, preferably 40 J or less, and the smaller the irradiation amount of ultraviolet rays, the more the reliability deterioration caused by the destruction of the members constituting the liquid crystal display element can be suppressed, and the ultraviolet irradiation time can be reduced. This is suitable because the production efficiency is increased.

As described above, when ultraviolet rays are applied to the liquid crystal alignment film and the liquid crystal layer while applying a voltage, the polymerizable compound reacts to form a polymer, and the direction in which the liquid crystal molecules are tilted is memorized by the polymer. The pretilt angle of the obtained liquid crystal display element can be set to a desired value, and the response speed can be increased. Further, when ultraviolet rays are applied to the liquid crystal alignment film and the liquid crystal layer while applying a voltage, a polyimide precursor having a side chain for vertically aligning the liquid crystal and a photoreactive side chain, and the polyimide precursor are imide. Since the photoreactive side chains of at least one polymer selected from the polyimide obtained by the conversion react with each other and the photoreactive side chains of the polymer react with the polymerizable compound, the liquid crystal display element obtained can be obtained. The response speed can be increased.

The pretilt angle of the liquid crystal display element depends on the liquid crystal alignment film used, that is, the liquid crystal alignment agent used, the polyimide precursor used, and the first photoradical generating diamine used. As described above, by using the polyimide precursor of the present invention, particularly the polyimide precursor having a relatively large amount of radicals generated, the amount of radicals generated during UV irradiation increases. Further, when the amount of radicals generated is large, the reaction of the above-mentioned polymerizable compound is promoted, so that the pretilt angle of the liquid crystal display element obtained with a small irradiation amount can be set to a desired value in the case of the same wavelength. Moreover, the response speed can be increased.
In general, the pretilt angle of a liquid crystal display element tends to deviate from 90 ° as the amount of UV irradiation when forming the liquid crystal display element increases.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.
The abbreviations and structures of the compounds and the methods for measuring each property in the following are as follows.

(solvent)
DMF: N, N-dimethylformamide THF: tetrahydrofuran NMP: N-methyl-2-pyrrolidone BCS: Butyl cellosolve (diamine)
DA-A: 1- (4- (2- (2,4-diaminophenoxy) ethoxy) phenyl) -2-methoxy-2-methylpropan-1-one DA-1: 1- (4- (2- (2- (2- (2- 2,4-Diaminophenoxy) ethoxy) phenyl) -2-hydroxy-2-methylpropan-1-one DA-2: 4- (4- (4-heptylcyclohexyl) phenoxy) benzene-1,3-diamine 3AMPDA: 3,5-Diamino-N- (pyridin-3-ylmethyl) benzamide (acid dianhydride)
BODA: Bicyclo [3,3,0] octane-2,4,6,8-tetracarboxylic dianhydride CBDA: 1,2,3,4-cyclobutanetetracarboxylic dianhydride (additive)
3AMP: 3-picorylamine

[ ^{1 1} H NMR]
Device: Fourier transform type superconducting nuclear magnetic resonance device (FT-NMR) INOVA-400 (manufactured by Varian) 400 MHz
Solvent: Deuterated chloroform (CDCl ₃ ) or deuterated dimethyl sulfoxide (DMSO-d ₆ )
Standard substance: Tetramethylsilane (TMS)
Accumulation number: 8 or 32.

[ ¹³ C { ¹ H} NMR]
Device: Fourier transform type superconducting nuclear magnetic resonance device (FT-NMR) INOVA-400 (manufactured by Varian) 100 MHz
Solvent: Deuterated chloroform (CDCl ₃ ) or deuterated dimethyl sulfoxide (DMSO-d ₆ )
Standard substance: Tetramethylsilane (TMS)
Accumulation number: 256.

[Molecular weight]
The molecular weights of the polyimide precursor and the imidized polymer were measured by a GPC (normal temperature gel permeation chromatography) apparatus, and were converted into polyethylene glycol and polyethylene oxide to have a number average molecular weight (hereinafter, also referred to as Mn) and a weight average molecular weight (hereinafter, also referred to as Mn). Hereinafter, it is also referred to as Mw).
GPC device: Room temperature gel permeation chromatography (GPC) device (SSC-7200) manufactured by Senshu Kagaku Co., Ltd.
Column: Made by Shodex (in series of KD803 and KD805)
Column temperature: 50 ° C
Eluent: N, N-dimethylformamide (as an additive, lithium bromide-hydrate (LiBr · H ₂ O) is 30 mmol / L, phosphoric acid / anhydrous crystal (o-phosphate) is 30 mmol / L, tetrahydrofuran. (THF) is 10 ml / L)
Flow velocity: 1.0 ml / min.

Standard samples for preparing calibration curves: TSK standard polyethylene oxide manufactured by Tosoh (weight average molecular weight (Mw) of about 900,000, 150,000, 100,000, 30,000) and polyethylene glycol manufactured by Polymer Laboratory (peak top). Molecular weight (Mp) about 12,000, 4,000, 1,000). For the measurement, in order to avoid overlapping peaks, a sample in which four types of 900,000, 100,000, 12,000, and 1,000 were mixed, and three types of 150,000, 30,000, and 4,000 were used. Two samples of the mixed sample are measured separately.

[Measurement of imidization rate]
The imidization rate of polyimide in the synthetic example was measured as follows. 1. Put 20 mg of polyimide powder into an NMR sample tube (NMR sampling tube standard, φ5 (manufactured by Kusano Kagaku)) and deuterate dimethyl sulfoxide (DMSO-d ₆ , 0.05% TMS (tetramethylsilane) mixture) (1. 0 ml) was added and ultrasonically applied to completely dissolve. This solution was measured for proton NMR at 500 MHz with an NMR measuring machine (JNW-ECA500) (manufactured by JEOL Datum). The imidization rate is determined by using a proton derived from a structure that does not change before and after imidization as a reference proton, and the peak integrated value of this proton and the proton peak derived from the NH group of amic acid appearing in the vicinity of 9.5 ppm to 10.0 ppm. It was calculated by the following formula using the integrated value.
Imidization rate (%) = (1-α · x / y) × 100
In the above formula, x is the integrated proton peak value derived from the NH group of amic acid, y is the integrated peak value of the reference proton, and α is one NH group proton of amic acid in the case of polyamic acid (imidization rate is 0%). It is the number ratio of the reference protons to.

[Synthesis of diamine compounds]
(Control Synthesis Example 1: Synthesis of Aromatic Diamine Compound (DA-1))

Step 1: 1-Synthesis of 4- (2,4-dinitrophenoxy) ethoxy) phenyl) -2-hydroxy-2-methylpropanol In a 2L four-necked flask equipped with a stir bar and a nitrogen introduction tube, 2,4- 100.0 g of dinitrofluorobenzene ([Mw: 186.10 g / mol], 0.538 mol), 120.6 g of 2-hydroxy-4'-(2-hydroxyethoxy) -2-methylpropiophenone ([Mw] : 224.25 g / mol], 0.538 mol), 81.7 g of triethylamine ([Mw: 101.19 g / mol], 0.807 mol), 1000 g of THF was added, and the mixture was refluxed for 24 hours. After completion of the reaction, the mixture was concentrated on a rotary evaporator, ethyl acetate was added, and the mixture was washed several times with pure water and physiological saline, and then dried over anhydrous magnesium sulfate.

Anhydrous magnesium sulfate was removed by filtration, concentrated on a rotary evaporator, and then recrystallized from ethyl acetate and normal hexane. 157.0 g of a milky white solid ([Mw: 390.34 g / mol], 0.402 mol, yield) : 75%) was obtained. It was confirmed by the nuclear magnetic resonance spectrum ( ¹ H-NMR spectrum) of the hydrogen atom in the molecule. The measurement data is shown below.
^{1 1} H NMR (400 MHz, CDCl ₃ ) δ: 8.75 (Ar: 1H), 8.48 to 8.45 (Ar: 1H), 8.09 to 8.05 (Ar: 2H), 7.34 ~ 7.31 (Ar: 1H) 7.00 to 6.96 (Ar: 2H), 4.55-4.63 (-CH2-: 2H), 4.52-4.49 (-CH2-: 2H) ), 4.16 (-OH: 1H), 1.66 to 1.60 (-CH3 × 2, 6H) Total: 18H.

Synthesis of Step2 1- (4- (2,4-diaminophenoxy) ethoxy) phenyl) -2-hydroxy-2-methylpropanone (DA-1) In a 1 L four-necked flask, the dinitrobenzene derivative obtained in Step1 was placed in 100. Weigh 10.0 g of 0 g ([Mw: 390.34 g / mol], 0.256 mol) and iron-doped platinum carbon (3 wt% manufactured by Evonic), add 500 ml of THF, and perform degassing under reduced pressure and hydrogen substitution. It was thoroughly carried out and reacted at room temperature for 24 hours.

After completion of the reaction, platinum carbon was removed with a PTFE membrane filter, and the filtrate was removed with a rotary evaporator to precipitate a solid. The obtained solid was washed with isopropyl alcohol by heating and further dried under reduced pressure to obtain 72.7 g ([Mw: 330.38 g / mol], 0.220 mol yield) of the target compound, a light pink solid. : 86%) was obtained. ^{1 1} H-NMR spectrum measurement data is shown below.
^{1 1} H NMR (400 MHz, CDCl ₃ ) δ: 8.09 to 8.05 (Ar: 2H), 7.01 to 6.97 (Ar: 2H), 6.70 to 6.68 (Ar: 1H) , 6.12 (Ar: 1H), 4.36-4.33 (-CH2-: 2H), 4.29-4.27 (-OH & -CH2-: 3H), 3.7 (-NH2: 2H) ), 3.39 (-NH2: 2H), 1.64 to 1.63 (-CH3 × 2: 6H) Total: 22H.

<Synthesis example 1>
Aromatic Diamine Compound (DA-A): Synthesis of 1- (4- (2- (2,4-diaminophenoxy) ethoxy) phenyl) -2-methoxy-2-methylpropan-1-one 5 steps shown below Aromatic diamine compound (DA-A) was synthesized by the above route. The aromatic diamine compound (DA-A) corresponds to the above-mentioned specific diamine compound.

First step: 2-hydroxy-2-methyl-1-(4-(2-((tetrahydro-2H-pyran-2-yl) oxy) ethoxy) phenyl) propan-1-one (DA-A-1) Synthesis of

IRGACURE2959 (2-hydroxy-1- (4- (2-hydroxyethoxy) phenyl) -2-methylpropan-1-one, 50.0 g, 223 mmol) was dissolved in THF (200 g) and p-toluenesulfonic acid was dissolved. Monohydrate (0.424 g, 2.23 mmol) was added, and 3,4-dihydro-2H-pyran (23.4 g, 279 mmol) was added dropwise over 10 minutes, and the mixture was reacted at room temperature for 3 hours. Then, the reaction solution is filtered and the filtrate is concentrated to obtain 2-hydroxy-2-methyl-1-(4-(2-((tetrahydro-2H-pyran-2-yl) oxy) ethoxy) phenyl). A crude product of propane-1-one was obtained (green liquid, 73.7 g).
¹ H NMR (DMSO-d ₆ ): δ 8.22 (d, J = 9.0 Hz, 2H, C ₆ H ₄ ), 7.02 (d, J = 9.0 Hz, 2H, C ₆ H ₄ ), 5.68 (s, 1H) , OH), 4.66 (t, J = 3.6 Hz, 1H, CH), 4.22 (t, J = 4.8 Hz, 2H, CH ₂ ), 4.07-3.92 (m, 1H, CH ₂ ), 3.81-3.70 (m) , 2H, CH ₂ ), 3.47-3.42 (m, 1H, CH ₂ ), 1.77-1.41 (m, 6H, CH ₂ ), 1.40 (s, 6H, C (CH ₃ ) ₂ ). ¹³ C { ¹ H } NMR (DMSO-d ₆ ): δ 202.4, 162.3, 162.1, 132.9, 127.9, 114.2, 98.5, 93.9, 93.6, 77.1, 70.2, 67.8, 65.5, 63.1, 62.0, 61.7, 59.9, 30.7, 30.6, 28.6, 25.6, 25.4, 20.8, 19.5 (each s).

Second step: 2-Methoxy-2-methyl-1-(4-(2-((tetrahydro-2H-pyran-2-yl) oxy) ethoxy) phenyl) propan-1-one (DA-A-2) Synthesis of

Sodium hydride (57.1 wt% purity, 15.0 g, 357 mmol) was suspended in THF (448 g) and cooled to 3 ° C. to convert the crude DA-A-1 (73.3 g) into THF (138 g). The dissolved solution was added dropwise at 3 ° C. over 15 minutes. Then, the mixture was stirred for 30 minutes, methyl iodide (41.0 g, 357 mmol) was added dropwise over 5 minutes, and the mixture was stirred at room temperature for 22 hours. Then, at room temperature, water (660 g) and toluene (586 g) are added in this order and stirred, the aqueous layer is discarded, the organic layer is washed twice with water (650 g), and the organic layer is concentrated to concentrate 2-methoxy. A crude product of -2-methyl-1-(4- (2-((tetrahydro-2H-pyran-2-yl) oxy) ethoxy) phenyl) propan-1-one was obtained (brown liquid, 80.1 g). ..
^{1 1} H NMR (DMSO-d ₆ ): δ 8.19 (d, J = 8.8 Hz, 2H, C ₆ H ₄ ), 7.06 (d, J = 8.8 Hz, 2H, C ₆ H ₄ ), 4.66 (s, 1H , CH), 4.24-4.22 (m, 2H, CH ₂ ), 3.97-3.92 (m, 1H, CH), 3.80-3.72 (m, 2H, CH ₂ ), 3.47-3.43 (m, 1H, CH), 3.08 (s, 3H, CH ₃ ), 1.71-1.60 (m, 2H, CH ₂ ), 1.53-1.46 (m, 4H, (CH ₂ ) ₂ ), 1.41 (s, 6H, C (CH ₃ ) ₂ ) . ¹³ C { ¹ H} NMR (DMSO-d ₆ ): δ 201.35, 162.6, 132.2, 127.5, 114.6, 98.5, 83.1, 67.9, 65.5, 61.7, 52.2, 30.6, 24.5, 24.9, 19.4 (each s).

Third step: Synthesis of 1- (4- (2-hydroxyethoxy) phenyl) -2-methoxy-2-methylpropan-1-one (DA-A-3)

A crude product of DA-A-2 (79.4 g) in a solution of p-toluenesulfonic acid monohydrate (0.469 g, 2.46 mmol) in a mixed solvent of methanol (397 g) and THF (80 g). ) Was dissolved in THF (79 g) and added over 3 minutes at room temperature. Then, the mixture was stirred for 2 hours to concentrate the reaction mixture, and it was confirmed that 20% of the raw material remained. Then, THF (350 g), water (290 g), and p-toluenesulfonic acid monohydrate (2.53 g, 13.3 mmol) were added to the residue, and the mixture was stirred at room temperature for 14 hours. Then, toluene (350 g) is added, and after stirring, the aqueous layer is discarded, the organic layer is washed twice with water (340 g), and the organic layer is concentrated to concentrate 1- (4- (2-hydroxyethoxy) phenyl. A crude product of -2-methoxy-2-methylpropan-1-one was obtained (brown liquid, 50.5 g).
^{1 1} H NMR (DMSO-d ₆ ): δ 8.20 (d, J = 9.0 Hz, 2H, C ₆ H ₄ ), 7.05 (d, J = 9.0 Hz, 2H, C ₆ H ₄ ), 4.96 (t, J) = 5.4 Hz, 1H, OH), 4.10 (t, J = 4.8 Hz, 2H, CH ₂ ), 3.97-3.92 (dt, J = 5.4, 4.8 Hz, 2H, CH ₂ ), 3.09 (s, 3H, CH ₃ ), 1.42 (s, 6H, C (CH ₃ ) ₂ ). ¹³ C { ¹ H} NMR (DMSO-d ₆ ): δ 200.3, 162.8, 132.2, 127.4, 114.6, 83.1, 70.2, 59.8, 52.2, 24.9 (each s).

Fourth step: Synthesis of 1- (4- (2- (2,4-dinitrophenoxy) ethoxy) phenyl) -2-methoxy-2-methylpropan-1-one (DA-A-4)

The crude product of DA-A-3 (45.7 g) was dissolved in DMF (79.9 g), 1-fluoro-2,4-dinitrobenzene (35.7 g, 192 mmol), and triethylamine (29.1 g, 29.1 g,). 288 mmol) was added, and the mixture was stirred at room temperature for 24 hours. Then, toluene (274 g) and water (274 g) were added and stirred, the aqueous layer was discarded, the organic layer was washed twice with water (274 g), and the organic layer was concentrated. Subsequently, the residue was purified by silica gel column chromatography (solvent: toluene / ethyl acetate = 3/1 (v / v), Rf = 0.3), and the eluate was concentrated. Then, 2-propanol (193 g) is added to the residue, and the mixture is stirred and filtered at room temperature. Then, 2-propanol (400 g) is added to the filter again, and the mixture is stirred and filtered at 60 ° C., and the filter is dried. , 1- (4- (2- (2,4-dinitrophenoxy) ethoxy) phenyl) -2-methoxy-2-methylpropane-1-one (light brown solid, 29.2 g, yield 30%) (4 steps)).
^{1 1} H NMR (DMSO-d ₆ ): δ 8.73 (d, J = 2.8 Hz, 1H, C ₆ H ₃ ), 8.50 (dd, J = 9.2, 2.8 Hz, 1H, C ₆ H ₃ ), 8.16 (d , J = 8.8 Hz, 2H, C ₆ H ₄ ), 7.65 (d, J = 9.2 Hz, 1H, C ₆ H ₃ ), 7.37 (d, J = 8.8 Hz, 2H, C ₆ H ₄ ), 4.71- 4.69 (m, 2H, CH ₂ ), 4.45-4.43 (m, 2H, CH ₂ ), 3.04 (s, 3H, CH ₃ ), 1.37 (s, 6H, C (CH ₃ ) ₂ ). ¹³ C { ¹ H} NMR (DMSO-d ₆ ): δ 201.4, 162.2, 156.0, 140.3, 139.2, 132.2, 129.7, 127.8, 121.6, 116.4, 114.7, 83.1, 69.6, 66.5, 52.2, 24.8 (each s).

Fifth step: Synthesis of 1- (4- (2- (2,4-dinitrophenoxy) ethoxy) phenyl) -2-methoxy-2-methylpropan-1-one (DA-A)

DA-A-4 (10.0 g, 24.7 mmol) was dissolved in THF, 1% platinum-carbon (0.2% Fe-doped, 59.5 wt% water content, 0.62 g) was added, and the hydrogen pressure was 0. The mixture was stirred under 2 to 0.5 MPa. After 3 hours, the completion of the reaction was confirmed by HPLC, the catalyst was filtered, the filtrate was concentrated, toluene (30 g) was added, the mixture was stirred at 65 ° C. for 30 minutes, and then cooled to 0 ° C. to obtain the precipitated solid. Filtration and drying gave 1- (4- (2- (2,4-diaminophenoxy) ethoxy) phenyl) -2-methoxy-2-methylpropan-1-one (purple solid, 7.23 g). , Yield 85%)
^{1 1} H NMR (DMSO-d ₆ ): δ 8.20 (d, J = 9.2 Hz, 2H, C ₆ H ₄ ), 7.08 (d, J = 9.2 Hz, 2H, C ₆ H ₄ ), 6.57 (d, J) = 8.4 Hz, 1H, C ₆ H ₃ ), 5.96 (d, J = 2.4 Hz, 1H, C ₆ H ₃ ), 5.77 (dd, J = 9.2, 2.8 Hz, 1H, C ₆ H ₃ ), 4.48 ( s, 2H, NH ₂ ), 4.42 (s, 2H, NH ₂ ), 4.34-4.32 (m, 2H, CH ₂ ), 4.12-4.10 (m, 2H, CH ₂ ), 3.08 (s, 3H, CH ₃₎ ), 1.41 (s, 6H, C (CH ₃ ) ₂ ). ¹³ C { ¹ H} NMR (DMSO-d ₆ ): δ 201.4, 162.6, 144.2, 139.6, 137.4, 132.3, 127.6, 116.3, 114.7, 102.7 , 101.8, 83.1, 68.9, 67.4, 52.2, 24.9 (each s).

(Examples 1 and 2)
<Synthesis of liquid crystal alignment agent>
BODA (10.01 g, 40.0 mmol), 3AMPDA (4.85 g, 20.0 mmol), DA-A (13.78 g, 40.0 mmol), DA-2 (15.22 g, 40.0 mmol) NMP ( After dissolving in 166.2 g) and reacting at 60 ° C. for 5 hours, CBDA (11.57 g, 59.0 mmol) and NMP (55.4 g) were added, and the mixture was reacted at 40 ° C. for 10 hours to prepare a polyamic acid solution. Obtained.
NMP is added to this polyamic acid solution (250 g) to dilute it to 6.5% by mass, acetic anhydride (45.9 g) and pyridine (14.2 g) are added as imidization catalysts, and the mixture is reacted at 70 ° C. for 3 hours. It was. This reaction solution was put into methanol (3300 ml), and the obtained precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 100 ° C. to obtain a polyimide powder (A). The imidization ratio of this polyimide was 72%, the number average molecular weight was 14,000, and the weight average molecular weight was 38,000.
NMP (44.0 g) was added to the obtained polyimide powder (A) (6.0 g), and the mixture was dissolved by stirring at 70 ° C. for 20 hours. To this solution, 6.0 g of 3AMP (1 mass% NMP solution), NMP (4.0 g) and BCS (40.0 g) were added, and the mixture was stirred at room temperature for 5 hours to obtain a liquid crystal aligning agent (A1).

<Manufacturing of liquid crystal cell>
Using the liquid crystal alignment agent (A1) obtained in Example 1, a liquid crystal cell was produced by the procedure as shown below.
The liquid crystal alignment agent (A1) obtained in Example 1 was spin-coated on the ITO surface of an ITO electrode substrate having an ITO electrode pattern having a pixel size of 100 μm × 300 μm and a line / space of 5 μm, respectively, at 80 ° C. After drying on the hot plate of No. 1 for 90 seconds, it was fired in a hot air circulation oven at 200 ° C. for 30 minutes to form a liquid crystal alignment film having a film thickness of 100 nm.
Further, the liquid crystal aligning agent (A1) was spin-coated on the ITO surface on which the electrode pattern was not formed, dried on a hot plate at 80 ° C. for 90 seconds, and then baked in a hot air circulation oven at 200 ° C. for 30 minutes. A liquid crystal alignment film having a film thickness of 100 nm was formed.
A 4 μm bead spacer was sprayed on the liquid crystal alignment film of one of the above two substrates, and then a sealant (solvent type thermosetting type epoxy resin) was printed on the bead spacer. Next, the surface of the other substrate on which the liquid crystal alignment film was formed was turned inside, and after bonding with the previous substrate, the sealant was cured to prepare an empty cell. A liquid crystal cell containing a polymerizable compound for PSA MLC-3023 (trade name manufactured by Merck & Co., Inc.) was injected into this empty cell by a reduced pressure injection method to prepare a liquid crystal cell.

<Measurement of pre-tilt angle>
<< UV irradiation: 6J / cm ² or 10J / cm ² >>
With a DC voltage of 15 V applied to the obtained liquid crystal cell, the liquid crystal cell was irradiated with UV from the outside of the liquid crystal cell through a bandpass filter of 365 nm at 6 J / cm ² or 10 J / cm ² . The illuminance of UV was measured using UV-MO3A manufactured by ORC. After that, for the purpose of inactivating the unreacted polymerizable compound remaining in the liquid crystal cell, UV (UV lamp: FLR40SUV32 /) was used using a UV-FL irradiation device manufactured by Toshiba Lighting & Technology Corporation in a state where no voltage was applied. A-1) was irradiated for 30 minutes.
Then, the pre-tilt angle of the pixel portion was measured for the cell after UV irradiation. The pre-tilt angle was measured using an LCD analyzer LCA-LUV42A manufactured by Meiryo Technica. The results are shown in Table 1.

<Measurement of response speed>
First, in a measuring device composed of a backlight, a set of polarizing plates in a cross-nicol state, and a photodetector in this order, the obtained liquid crystal cells were arranged between the set of polarizing plates. At this time, the pattern of the ITO electrode on which the line / space was formed was set to an angle of 45 ° with respect to the cross Nicol. Then, a square wave with a voltage of ± 7 V and a frequency of 1 kHz is applied to the above liquid crystal cell, and the change until the brightness observed by the light amount detector is saturated is captured by an oscilloscope, and the brightness when no voltage is applied is obtained. A voltage of 0% and ± 7V was applied, the saturated brightness value was set to 100%, and the time required for the brightness to change from 10% to 90% was defined as the response speed.

(Control Examples 1 and 2)
<Synthesis of control liquid crystal alignment agent>
A control liquid crystal alignment agent (as in Example 1) except that DA-1 (13.22 g, 40.0 mmol) was used instead of “DA-A (13.78 g, 40.0 mmol)” in Example 1. B1) was synthesized. Specifically, a control liquid crystal alignment agent (B1) was synthesized as follows.
That is, BODA (10.01 g, 40.0 mmol), 3AMPDA (4.85 g, 20.0 mmol), DA-1 (13.22 g, 40.0 mmol), DA-2 (15.22 g, 40.0 mmol). Dissolve in NMP (164.6 g) and react at 60 ° C. for 5 hours, then add CBDA (11.57 g, 59.0 mmol) and NMP (54.9 g) and react at 40 ° C. for 10 hours to polyamic acid. A solution was obtained.
NMP is added to this polyamic acid solution (250 g) to dilute it to 6.5% by mass, acetic anhydride (46.4 g) and pyridine (14.4 g) are added as imidization catalysts, and the mixture is reacted at 70 ° C. for 3 hours. It was. This reaction solution was put into methanol (3300 ml), and the obtained precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 100 ° C. to obtain a polyimide powder (B). The imidization ratio of this polyimide was 73%, the number average molecular weight was 23000, and the weight average molecular weight was 64000.
NMP (44.0 g) was added to the obtained polyimide powder (B) (6.0 g), and the mixture was dissolved by stirring at 70 ° C. for 20 hours. To this solution, 6.0 g of 3AMP (1 mass% NMP solution), NMP (4.0 g) and BCS (40.0 g) were added, and the mixture was stirred at room temperature for 5 hours to obtain a liquid crystal aligning agent (B1).

<Making a control liquid crystal cell, measuring its pretilt angle, and measuring its response speed>
A control liquid crystal cell was produced in the same manner as in Example 1 except that the liquid crystal alignment agent (B1) was used instead of the “liquid crystal alignment agent (A1)” in Example 1.
Further, the obtained control liquid crystal cell was subjected to the same operation as in the examples, and the pretilt angle and the response speed were measured. The results are shown in Table 1.

The following can be seen from Table 1.
That is, the control liquid crystal cells of Control Examples 1 and 2 (using the control liquid crystal alignment agent (B1) obtained by using the control diamine (DA-1)) and Examples 1 and 2 (aromatic diamine compound (DA-A)). ), The liquid crystal cells of Examples 1 and 2 have a pretilt angle of more than 90 ° when irradiated with the same amount of light. ing.
Further, it can be seen that the liquid crystal cells of Examples 1 and 2 can have a desired pretilt angle and a desired response speed with a lower UV irradiation amount than the liquid crystal cells of Control Examples 1 and 2. This is because the amount of radicals generated by the aromatic diamine compound (DA-A) used in the liquid crystal cells of Examples 1 and 2 during UV irradiation is larger than that of the diamine (DA-1) used in the control liquid crystal cell. Depends on.
Since the liquid crystal cells of Examples 1 and 2 may have a smaller amount of UV irradiation at the same wavelength than the control liquid crystal cells of Control Examples 1 and 2, the damage to the liquid crystal due to the shortening of the UV irradiation time can be reduced, and the liquid crystal can be produced. Cost can be suppressed.

Claims (14)

A polyimide precursor using the first photoradical generating diamine.
The conditions are the same as those of the second polyimide precursor formed under the same conditions as the polyimide precursor except that the first photoradical generating diamine is replaced with the second photoradical generating diamine represented by the formula (1). It is characterized by a large amount of radicals generated during light irradiation underneath .
The first photoradical generating diamine is the formula (A).
(In the formula, Ar represents an aromatic hydrocarbon group which may have a substituent and represents
R ¹⁰¹ represents a divalent organic group
R ^{102 to} R ¹⁰⁴ each independently represent a monovalent organic group)
Has the structure of
Any one of the above R ^{102 to} R ¹⁰⁴ is −OR ¹¹¹ (R ¹¹¹ is a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms substituted with an unsubstituted or fluorine atom (R ¹¹¹ ). -CH _2- or -CF _2- in the alkyl group is replaced with -CH = CH- or a group selected from the next group G (however, the groups selected from the group G are not adjacent to each other). It may be substituted with (group G: -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, a divalent carbon ring or a divalent heterocycle). ) And
The other two are independently linear or branched or cyclic alkyl groups with 1 to 20 carbon atoms , -OR ¹¹² (R ¹¹² is unsubstituted or substituted with a fluorine atom and has 1 to 20 carbon atoms. Represents a group selected from the group consisting of a linear or branched or cyclic alkyl group, an aryl group having 6 to 20 carbon atoms which may have a substituent), a benzyl group, or a phenethyl group. (If the other two are the alkyl group or -OR ¹¹² , they may combine with each other to form a ring) , said polyimide precursor.

The polyimide precursor according to claim 1, wherein the wavelength of light at the time of light irradiation is 300 nm to 400 nm. The polyimide precursor according to claim 1 or 2, wherein the first photoradical generating diamine is 0.1 to 100 mol% in 100 mol% of the total diamines constituting the polyimide precursor. The -R ^101- is -T _1- S-T _2-
(In the formula,
T ₁ and T ₂ are independent, single bond, -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, -CH ₂ O-, -N (CH ₃ ). -, -CON (CH ₃ )-, or -N (CH ₃ ) CO-,
S is a single bond, or an alkylene group having 1 to 20 carbon atoms substituted with an unsubstituted or fluorine atom (-CH _2- or -CF _2- in the alkylene group is -CH = CH-, or the following. It may be replaced with a group selected from the group G (where the groups selected from the group G are not adjacent to each other) (group G: -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, divalent carbocycle or divalent heterocycle)))
The polyimide precursor according to any one of claims 1 to 3 represented by. The polyimide precursor according to any one of claims 1 to 4 , wherein Ar is a phenylene group. The first photoradical generating diamine is according to any one of claims 1 to 5 represented by the following formula (2) (in which Ar and R ^{101 to} R ¹⁰⁴ have the same definition as described above). The polyimide precursor described.

The polyimide precursor according to any one of claims 1 to 6 , wherein the first photoradical generating diamine is represented by the following formula (3).

The polyimide precursor according to any one of claims 1 to 7 , further comprising a side chain for vertically aligning the liquid crystal. The polyimide precursor according to any one of claims 1 to 8 , further comprising a side chain containing a photoreactive group in the structure. A polyimide obtained by imidizing the polyimide precursor according to any one of claims 1 to 9 . A liquid crystal alignment agent having the polyimide precursor according to any one of claims 1 to 9 and / or the polyimide according to claim 10 . The eleventh aspect of claim 11 which contains a polymerizable compound in a liquid crystal and / or a liquid crystal alignment film and is used for producing a liquid crystal display element obtained by reacting the polymerizable compound by irradiating ultraviolet rays while applying a voltage. The liquid crystal alignment agent described. A liquid crystal alignment film formed by having the liquid crystal alignment agent according to claim 11 or 12 . A liquid crystal display element including the liquid crystal alignment film according to claim 13 .