TWI772371B - Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Abstract

式(1)中，X表示-(CH₂ )_n -，n為8或9之自然數。 　　式(2)中，Y₁ 為具有胺基等之2價有機基，B₁ 、B₂ 分別獨立為氫原子等。The present invention relates to a liquid crystal aligning agent comprising: a polymer (A) obtained from a polyamic acid obtained by using a tetracarboxylic dianhydride component and a diamine component containing a diamine represented by the following formula (1), and the At least one selected from the imidized polymers of polyamic acid; and the polymer (B), which is obtained by using a tetracarboxylic dianhydride component and a diamine component containing a diamine represented by the following formula (2) At least one selected from the obtained polyamic acid and the imidized polymer of the polyamic acid. According to the present invention, a liquid crystal alignment agent, a liquid crystal alignment film and a liquid crystal display element can be provided which can obtain a liquid crystal alignment film with excellent voltage retention, rapid relaxation of accumulated charges, and good liquid crystal alignment stability.

In formula (1), X represents -(CH ₂ ) _n -, and n is a natural number of 8 or 9. In formula (2), Y ₁ is a divalent organic group having an amine group or the like, and B ₁ and B ₂ are each independently a hydrogen atom or the like.

Description

Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element

The present invention relates to a novel liquid crystal alignment agent, a liquid crystal alignment film and a liquid crystal display element using the same.

Liquid crystal display elements have been widely used as display parts of personal computers, mobile phones, smart phones, televisions, and the like. The liquid crystal display element includes, for example, a liquid crystal layer sandwiched between an element substrate and a color filter substrate, a pixel electrode and a common electrode for applying an electric field to the liquid crystal layer, an alignment film for controlling the alignment of liquid crystal molecules in the liquid crystal layer, and a pair of electrodes supplied to the pixel electrode. Thin film transistors (TFTs) that switch electrical signals. As a driving method of liquid crystal molecules, a vertical electric field method such as a TN method and a VA method, and a horizontal electric field method such as an IPS method and an FFS method are known. The horizontal electric field method in which electrodes are formed only on one side of the substrate, and an electric field is applied in a direction parallel to the substrate, has a wider viewing angle than the conventional vertical electric field method in which a voltage is applied to electrodes formed on the upper and lower substrates to drive the liquid crystal, and it is known that As a liquid crystal display element that can display high quality.

Although the liquid crystal cell of the lateral electric field type has excellent viewing angle characteristics, since there are few electrode portions formed in the substrate, when the voltage holding ratio is low, a sufficient voltage cannot be applied to the liquid crystal, which reduces the display contrast. In addition, when the stability of the liquid crystal alignment is small, the liquid crystal will not return to the initial state when the liquid crystal is driven for a long time, which may cause a decrease in contrast or an afterimage. Therefore, the stability of the liquid crystal alignment is important. Furthermore, static electricity is easily accumulated in the liquid crystal cell. Even with the application of positive and negative asymmetrical voltages generated by driving, the electric charges will be accumulated in the liquid crystal cell, and the accumulated electric charges will affect the display as liquid crystal alignment disorder or afterimage. , the display quality of the liquid crystal element is significantly reduced. In addition, even if the liquid crystal cell is irradiated by the backlight immediately after driving, the electric charges are accumulated, and after-images are generated even in short-time driving, and problems such as changes in the size of flicker during driving occur.

Patent Document 1 discloses a liquid crystal aligning agent containing a specific diamine and an aliphatic tetracarboxylic acid derivative as a liquid crystal aligning agent having excellent voltage retention and reduced charge accumulation when used in a liquid crystal display element of such a transverse electric field system . In addition, as a method of shortening the time until the afterimage disappears, it has been proposed to use an alignment film with a low volume resistivity as in Patent Document 2, or an alignment whose volume resistivity is not easily changed by the backlight of a liquid crystal display element as in Patent Document 3. membrane method. However, along with the higher performance of liquid crystal display elements, the required properties of the liquid crystal alignment film have become more severe, and it is difficult to fully satisfy all the required properties with these conventional technologies. [Prior Art Literature]

[Patent Document 1] International Publication No. WO2004/021076 Specification [Patent Document 2] International Publication No. WO2004/053583 Specification [Patent Document 3] International Publication No. WO2013/008822 Specification

The subject of the present invention is to provide a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element that are excellent in voltage retention, rapidly accumulate charge, and obtain a liquid crystal alignment film with good liquid crystal alignment stability.

As a result of intensive research to solve the above-mentioned problems, the present inventors have found that various properties can be improved by introducing a specific structure into a polymer contained in a liquid crystal aligning agent, and have completed the present invention. The present invention is based on this finding, and the gist is as follows.

<1> A liquid crystal aligning agent comprising: a polymer (A) obtained from a polyamic acid obtained by using a tetracarboxylic dianhydride component and a diamine component containing a diamine represented by the following formula (1), and At least one selected from the imidized polymers of the polyamic acid; and the polymer (B), which is obtained by using a tetracarboxylic dianhydride component and a diamine containing a diamine represented by the following formula (2) at least one selected from the polyamides obtained from the ingredients and the imidized polymers of the polyamides,

In formula (1), X represents -(CH ₂ ) _n -, n represents the number of -(CH ₂ )- and is a natural number of 8 or 9, any -(CH ₂ )- can be independently processed from The groups selected from -O-, -S-, -COO-, -OCO-, -CONH- and -NHCO- are substituted on the condition that these groups are not adjacent, and R ₁ and R ₂ are independently monovalent organic groups, p1 and p2 are each independently an integer from 0 to 4.

In the formula (2), Y ₁ is a divalent organic group having at least one structure selected from the group consisting of an amino group, an imino group and a nitrogen-containing heterocycle, and B ₁ and B ₂ are each independently a hydrogen atom or can be Alkyl, alkenyl, and alkynyl groups having 1 to 10 carbon atoms as substituents.

<2> The liquid crystal aligning agent according to the aforementioned <1>, wherein Y ₁ in the formula (2) is at least one selected from the structures of the following formulas (YD-1) to (YD-5),

(In formula (YD-1), A ₁ is a nitrogen atom-containing heterocycle with 3 to 15 carbon atoms, Z ₁ is a hydrogen atom or a hydrocarbon group with 1 to 20 carbon atoms that may have a substituent, formula (YD-2) Among them, W ₁ is a hydrocarbon group with 1 to 10 carbon atoms, A ₂ is a monovalent organic group with a nitrogen atom-containing heterocyclic ring with a carbon number of 3 to 15, or a di-substituted aliphatic group with a carbon number of 1 to 6 Amino group, in formula (YD-3), W ₂ is a divalent organic group with 6 to 15 carbon atoms and 1 to 2 benzene rings, and W ₃ is an alkylene group or a biphenylene group with a carbon number of 2 to 5 Or a divalent organic group with a carbon number of 12 to 18 containing a nitrogen atom-containing heterocyclic ring, Z ₂ is a hydrogen atom, an alkyl group with a carbon number of 1 to 5 or a benzene ring, a is an integer of 0 to 1, and the formula (YD- 4) in, A ₃ is the heterocyclic ring containing nitrogen atom of carbon number 3～15, in formula (YD-5), A ₄ is the heterocyclic ring containing nitrogen atom of carbon number 3～15, W ₅ is carbon number 2 ~5 alkylene groups).

<3> The liquid crystal aligning agent according to the aforementioned <1> or <2>, wherein A ₁ and A ₂ described in the formulae (YD-1), (YD-2), (YD-4) and (YD-5) , A ₃ and A ₄ are selected from pyrrolidine, pyrrole, imidazole, pyrazole, oxazole, thiazole, piperidine, piperazine, pyridine, pyrazine, indole, benzimidazole, quinoline, isoquinoline and carbazole At least 1 species selected from the group.

<4> The liquid crystal aligning agent according to any one of the aforementioned <1> to <3>, wherein Y ₁ in the formula (2) is selected from the structures having the following formulas (YD-6) to (YD-22) at least one of the group of divalent organic groups of ,

(In formula (YD-17), h is an integer of 1 to 3, and in formula (YD-14), (YD-21) and (YD-22), j is an integer of 0 to 3).

<5> The liquid crystal aligning agent according to any one of the aforementioned <1> to <4>, wherein Y ₁ in the formula (2) is derived from the above formulas (YD-14), (YD-18), (YD- 21) and (YD-22) at least one selected from the group consisting of divalent organic groups of the structure.

<6> A liquid crystal alignment film obtained by coating and firing the liquid crystal alignment agent according to any one of the aforementioned <1> to <5>.

<7> A liquid crystal display element including the liquid crystal alignment film of the above-mentioned <6>.

By using the liquid crystal alignment agent of the present invention, a liquid crystal alignment film with excellent voltage retention, rapid relaxation of accumulated charges, good stability of liquid crystal alignment, and a liquid crystal display element with excellent display characteristics can be provided. It is not clear why the above-mentioned problems can be solved by the present invention, but it is considered as follows. The above-mentioned structure (2) of the polymer contained in the liquid crystal aligning agent of the present invention has a conjugated structure. Thereby, for example, in a liquid crystal alignment film, the transfer of electric charges can be promoted, and the relaxation of accumulated electric charges can be promoted.

The liquid crystal alignment agent of the present invention is a composition for forming a liquid crystal alignment film, and is characterized by containing a liquid crystal alignment agent containing a specific polymer (A) obtained from a diamine represented by the above formula (1) and a The specific polymer (B) obtained by the diamine which has the structure of the said formula (2). That is, in other words, the present invention relates to a polymer composition having liquid crystal alignment properties of the specific polymer (A) and the specific polymer (B).

The content of the specific polymer (A) and the specific polymer (B), relative to the total amount of the specific polymer (A) and the specific polymer (B), the specific polymer (A) is 5 to 90% by weight, more preferably 10 to 50% by weight. That is, the specific polymer (B) is 95 to 10% by weight, more preferably 90 to 50% by weight, based on the total amount of the specific polymer (A) and the specific polymer (B). When the specific polymer (A) is too small, the stability of the liquid crystal alignment is deteriorated, and when the specific polymer (B) is too small, the relaxation property of the accumulated charge is deteriorated. Each of the specific polymer (A) and the specific polymer (B) contained in the liquid crystal aligning agent of the present invention may be one type or two or more types.

<Polymer of component (A)> The polymer of the present invention is a polymer obtained by containing a diamine component of the diamine represented by the above formula (1) and a dianhydride component containing a tetracarboxylic dianhydride. Specifically, polyamic acid, polyamic acid ester, polyimide, polyurea, polyamide, etc. are mentioned, but from the viewpoint of use as a liquid crystal aligning agent, it is preferably self-contained by the following formula (3 At least one selected from the polyimide precursor of the structural unit represented by ) and the polyimide of the imide compound thereof. In the heating step after polarized light irradiation, the polyimide precursor is more preferable from the viewpoint of realignment with higher order due to more free rotation sites in the polymer.

In the above formula (3), X ₁ is a tetravalent organic group derived from a tetracarboxylic acid derivative, Y ₁₁ is a divalent organic group derived from a diamine of the formula (1), and R ₁₁ is a hydrogen atom or a carbon number of 1 ~5 alkyl groups. From the viewpoint of the ease of imidization by heating, R ₁₁ is preferably a hydrogen atom, a methyl group or an ethyl group, more preferably a hydrogen atom.

<Diamine having a specific structure> The liquid crystal aligning agent of the present invention contains a polymer (A) obtained by using a tetracarboxylic dianhydride component and a diamine component containing a diamine represented by the following formula (1). At least one selected from the polyamide and the imidized polymer of the polyamide; and the polymer (B), which is represented by using a tetracarboxylic dianhydride component and containing the following formula (2) At least one selected from the group consisting of a polyamide obtained as a diamine component of a diamine and an imidized polymer of the polyamide; and an organic solvent.

(In formula (1), X represents -(CH ₂ ) _n -, n represents the number of -(CH ₂ )- and is a natural number of 8 or 9, any -(CH ₂ )- can be independently processed by The radicals selected from -O-, -S-, -COO-, -OCO-, -CONH- and -NHCO- are substituted on the condition that these radicals are not adjacent, and R ₁ and R ₂ are independently monovalent organic radicals. , p1 and p2 are independently integers from 0 to 4).

The monovalent organic group here includes an alkyl group having 1 to 10, preferably 1 to 3 carbon atoms, an alkenyl group, an alkoxy group, a fluoroalkyl group, a fluoroalkenyl group, or a fluoroalkoxy group. Among them, the monovalent organic group is preferably a methyl group.

In addition, when the total number of atoms of carbon atoms participating in the length of the main chain, oxygen atoms, sulfur atoms, and nitrogen atoms is an even number in the number of atoms of X, the linearity of the resulting polymer becomes high, and after grinding or after irradiation with polarized ultraviolet rays. In the heating step, since a higher order realignment can be obtained, a liquid crystal alignment film with high alignment control ability can be obtained, which is preferable. In addition, the total number of carbon atoms, oxygen atoms, sulfur atoms, and nitrogen atoms participating in the length of the main chain is defined as 1 per methylene group in the main chain, and 1 per ether bond. , the total when the number of thioether bonds per 1 is 1, the number of ester bonds per 1 is 2, and the number of amide bonds per 1 is 2.

Any -(CH ₂ )- in X, when the hydrogen bonding force is weak, is preferably through any one of -O-, -S-, -COO- and -OCO- from the viewpoint of realignment in a higher order. is replaced, particularly preferably -O-.

As p1 and p2, 0 is preferable from the viewpoint that there are few steric hindrances and the phenyl groups are overlapped with each other so that higher order realignment is possible.

In -(CH ₂ ) _n - of the diamine of the above formula (1), when n is 8 or more, when the liquid crystal alignment agent blended with the polymer (B) is applied on the substrate, the alignment restriction force is higher. The migration of the polymer (A) toward the upper layer, that is, toward the interface on the non-substrate side, is high, and thus contributes to the improvement of the alignment. In addition, when n is 10 or more, the alignment restricting force of the polymer (A) itself is greatly reduced. Therefore, when n is not 8 or 9, the effect of the present invention cannot be obtained. Although the following can be illustrated as a specific example of these diamines, it is not limited to these.

Here, when r is 6 in the above formula, or t is 2 or 4, the linearity of the obtained polymer becomes high, and in the heating step after polarized light irradiation, realignment can be performed in a higher order, and high imparting A liquid crystal alignment film with alignment control capability.

<Tetracarboxylic dianhydride> X ₁ is a tetravalent organic group derived from a tetracarboxylic acid derivative, and its structure is not particularly limited. And X ₁ in the polyimide precursor is due to the solubility of the polymer to the solvent or the coatability of the liquid crystal alignment agent, the liquid crystal alignment when used as a liquid crystal alignment film, the voltage retention rate, the accumulation of electric charges, etc. Necessary It can be appropriately selected according to the degree of the characteristics, and may be one kind or two or more kinds can be mixed in the same polymer.

When particularly specific examples of X ₁ are shown, the structures of formulae (X-1) to (X-46) disclosed in Item 13 to Item 14 of International Publication No. 2015/119168 are mentioned.

The preferred structure of X ₁ is shown below, but the present invention is not limited to this.

Among these, (A-1) and (A-2) are preferable from the viewpoint of photoreactivity, alignment of liquid crystal, and voltage retention.

<Polymer (other structural unit)> The polyimide precursor containing the structural unit represented by the formula (3) may contain the structure represented by the following formula (4) within the range that does not impair the effect of the present invention At least one selected from the polyimide of the unit and its imide.

In the formula (4), X ₂ is a tetravalent organic group derived from a tetracarboxylic acid derivative, Y ₁₂ is a divalent organic group derived from a diamine, and R ₁₂ is the same as that of R ₁₁ in the aforementioned formula (3), R ₂₂ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Furthermore, at least one of the two R ₂₂ is preferably a hydrogen atom.

As X ₂ , the structures of the formulae (X-1) to (X-46) disclosed in Items 13 to 14 of the above-mentioned International Publication No. 2015/119168 are exemplified, and the above-mentioned (A-1) to (A -21) structure.

Y ₁₂ is a divalent organic group derived from diamine, and its structure is not particularly limited. And Y ₁₂ is appropriately selected according to the solubility of the polymer to the solvent or the coatability of the liquid crystal alignment agent, the degree of liquid crystal alignment when used as a liquid crystal alignment film, the voltage retention rate, the accumulated charge and other necessary characteristics. The same polymer may exist alone or in combination of two or more.

In particular, specific examples of Y ₁₂ include the structure of formula (2) disclosed in Item 4 of International Publication No. 2015/119168, and the formulae (Y-1) to (Y-97 disclosed in Item 8 to Item 12) ), (Y-101)~(Y-118) structure; International Publication 2013/008906, the divalent organic group with two amine groups removed from the formula (2) disclosed in Item 6 of International Publication 2013/008906; International Publication 2015/122413 Divalent organic group with two amine groups removed from formula (1) disclosed in item 8; structure of formula (3) disclosed in item 8 of International Publication 2015/060360; Japanese Laid-Open Patent Publication 2012-173514-8 The divalent organic group that removes 2 amine groups from the formula (1) described in the item; the divalent organic group that removes 2 amine groups from the formula (A)~(F) disclosed in the 9th item of International Publication 2010-050523 Base et al.

As a preferable structure of _Y12 , the structure of following formula (5) is mentioned.

In formula (5), R ³² is a single bond or a divalent organic group, preferably a single bond. R ³³ is a structure represented by -(CH ₂ ) _n -. n is an integer of 2-10, Preferably it is 3-7. And any -CH ₂ - can also be substituted by ether, ester, amide, urea, and urethane bonds in non-adjacent conditions. R ³⁴ is a single bond or a divalent organic group. Any hydrogen atom on the benzene ring may be substituted with a monovalent organic group, preferably a fluorine atom or a methyl group.

Specific examples of the structures represented by the formula (5) include the following structures, but are not limited to these.

When the polyimide precursor containing the structural unit represented by the formula (3) also contains the structural unit represented by the formula (4), the structural unit represented by the formula (3) is relative to the formula (3) and the formula (4). ) in total, preferably 30 mol% to 100 mol%, more preferably 50 mol% to 100 mol%, and particularly preferably 70 mol% to 100 mol%.

<Polymer of component (B)> The component (B) used in the liquid crystal aligning agent of the present invention is a polyamic acid obtained by using a tetracarboxylic dianhydride component and a diamine component containing the diamine represented by the above formula (2). and at least one polymer selected from the imidized polymers of the polyamic acid.

<Tetracarboxylic dianhydride component> The tetracarboxylic dianhydride used for the production of the component (B) of the present invention includes tetracarboxylic dianhydride represented by the following formula (6).

In the formula, as X ₃ , the structure selected from the above-mentioned (A-1) to (A-21) described in the (A) component is exemplified. Moreover, in the manufacture of (B) component, the tetracarboxylic dianhydride component used may be one type, or two or more types may be sufficient as it.

<Diamine component> The diamine component used for manufacture of the liquid crystal aligning agent of this invention contains the diamine of the said formula (2). In formula (2), Y ₁ is a divalent organic group having at least one structure selected from the group consisting of an amino group, an imine group and a nitrogen-containing heterocycle, and B ₁ to B ₂ are each independently a hydrogen atom or can be Alkyl, alkenyl, and alkynyl groups having 1 to 10 carbon atoms as substituents.

Specific examples of the above-mentioned alkyl group include methyl group, ethyl group, propyl group, butyl group, tert-butyl group, hexyl group, octyl group, decyl group, cyclopentyl group, cyclohexyl group and the like. Examples of the alkenyl group include those obtained by substituting one or more CH—CH existing in the above-mentioned alkyl group with a C=C structure, and more specifically, vinyl group, allyl group, 1-propenyl group, isopropenyl group, and 2-butanyl group. Alkenyl, 1,3-butadienyl, 2-pentenyl, 2-hexenyl, cyclopropenyl, cyclopentenyl, cyclohexenyl and the like. Examples of the alkynyl group include those obtained by substituting one or more CH ₂ -CH ₂ existing in the alkyl group with a C≡C structure, and more specifically, an ethynyl group, a 1-propynyl group, a 2-propynyl group, and the like.

The above-mentioned alkyl group, alkenyl group, and alkynyl group may have a substituent as long as the total number of carbon atoms is 1 to 10, and further, a ring structure may be formed by the substituent. In addition, the formation of a ring structure by a substituent refers to a case where the substituents or the substituent and a part of the parent skeleton are bonded to each other to form a ring structure.

Examples of the substituent include a halogen group, a hydroxyl group, a thiol group, a nitro group, an aryl group, an organooxy group, an organothio group, an organosilyl group, an acyl group, an ester group, a thioester group, a phosphate group, an acyl group Amine, alkyl, alkenyl, alkynyl.

As a halogen group of a substituent, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned. The aryl group as the substituent includes a phenyl group. The aryl group may be further substituted with the aforementioned other substituents.

The organic oxy group as a substituent can show a structure represented by O-R. The R may be the same or different, and the above-mentioned alkyl group, alkenyl group, alkynyl group, aryl group and the like can be exemplified. These Rs may be further substituted with the aforementioned substituents. Specific examples of the alkyloxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, and an octyloxy group.

The organosulfur group as a substituent may have a structure represented by -S-R. As this R, the above-mentioned alkyl group, alkenyl group, alkynyl group, aryl group, etc. can be illustrated. These Rs may be further substituted with the aforementioned substituents. Specific examples of the alkylthio group include methylthio, ethylthio, propylthio, butylthio, pentylthio, hexylthio, heptylthio, octylthio and the like.

The organosilyl group as a substituent may exhibit a structure represented by -Si-(R) ₃ . The R may be the same or different, and the above-mentioned alkyl group, alkenyl group, alkynyl group, aryl group and the like can be exemplified. These Rs may be further substituted with the aforementioned substituents. Specific examples of the alkylsilyl group include trimethylsilyl, triethylsilyl, tripropylsilyl, tributylsilyl, tripentylsilyl, trihexylsilyl, heptyldimethylsilyl Silyl, hexyldimethylsilyl, etc.

The acyl group as a substituent may have a structure represented by -C(O)-R. As this R, the above-mentioned alkyl group, alkenyl group, aryl group, etc. can be illustrated. These Rs may be further substituted with the aforementioned substituents. Specific examples of the acyl group include a carboxyl group, an acetyl group, a propionyl group, a butyl group, an isobutyl group, a pentamyl group, an isopentyl group, a benzyl group, and the like.

The ester group as a substituent may show a structure represented by -C(O)O-R or -OC(O)-R. As this R, the above-mentioned alkyl group, alkenyl group, alkynyl group, aryl group, etc. can be illustrated. These Rs may be further substituted with the aforementioned substituents.

The thioester group as a substituent may show a structure represented by -C(S)O-R or -OC(S)-R. As this R, the above-mentioned alkyl group, alkenyl group, alkynyl group, aryl group, etc. can be illustrated. These Rs may be further substituted with the aforementioned substituents.

The phosphate group as a substituent may show a structure represented by -OP(O)-(OR) ₂ . The R may be the same or different, and the above-mentioned alkyl group, alkenyl group, alkynyl group, aryl group and the like can be exemplified. These Rs may be further substituted with the aforementioned substituents.

The amido group as a substituent may be represented by -C(O)NH ₂ , or -C(O)NHR, -NHC(O)R, -C(O)N(R) ₂ , -NRC(O)R The structure of the representation. The R may be the same or different, and the above-mentioned alkyl group, alkenyl group, alkynyl group, aryl group and the like can be exemplified. These Rs may be further substituted with the aforementioned substituents.

The aryl group as a substituent is the same as the above-mentioned aryl group. The aryl group may be further substituted with the aforementioned other substituents.

The alkyl group as a substituent is the same as the above-mentioned alkyl group. The alkyl group may be further substituted with the aforementioned other substituents.

Examples of the alkenyl group as a substituent include the same ones as the aforementioned alkenyl group. The alkenyl group may be further substituted with the aforementioned other substituents.

Examples of the alkynyl group as the substituent include the same ones as the aforementioned alkynyl group. The alkynyl group may be further substituted with the aforementioned other substituents.

Generally, when a bulky structure is introduced, there is a possibility that the reactivity of the amine group or the alignment of the liquid crystal may be lowered, so B ₁ and B ₂ are preferably a hydrogen atom or an alkane having 1 to 5 carbon atoms which may have a substituent. group, particularly preferably a hydrogen atom, a methyl group or an ethyl group.

The structure of Y ₁ in the formula (2) is not particularly limited as long as it has at least one structure selected from the group consisting of an amino group, an imino group, and a nitrogen-containing heterocycle. In particular, specific examples thereof include at least one selected from the group consisting of an amino group represented by the following formulae (YD-1) to (YD-5), an imino group, and a nitrogen-containing heterocyclic ring. Constructed divalent organic radical.

In formula (YD-1), A ₁ is a nitrogen atom-containing heterocyclic ring with 3 to 15 carbon atoms, and Z ₁ is a hydrogen atom or a hydrocarbon group with 1 to 20 carbon atoms that may have a substituent.

In formula (YD-2), W ₁ is a hydrocarbon group with 1 to 10 carbon atoms, and A ₂ is a monovalent organic group with a nitrogen atom-containing heterocyclic ring with a carbon number of 3 to 15 or an aliphatic group with a carbon number of 1 to 6 Substituted disubstituted amine group.

In formula (YD-3), W ₂ is a divalent organic group with 6 to 15 carbon atoms and 1 to 2 benzene rings, W ₃ is an alkylidene group or a biphenylene group with a carbon number of 2 to 5 or contains The nitrogen atom heterocycle is a divalent organic group with 12 to 18 carbon atoms, Z ₂ is a hydrogen atom, an alkyl group with 1 to 5 carbon atoms or a benzene ring, and a is an integer of 0 to 1.

In formula (YD-4), A ₃ is a nitrogen atom-containing heterocyclic ring having 3 to 15 carbon atoms.

In formula (YD-5), A ₄ is a nitrogen atom-containing heterocyclic ring having 3 to 15 carbon atoms, and W ₅ is an alkylene group having 2 to 5 carbon atoms.

As A ₁ , A ₂ , A ₃ and A ₄ of formulas (YD-1), (YD-2), (YD-4) and (YD-5), the nitrogen atom-containing heterocyclic ring having 3 to 15 carbon atoms, If it is a conventional structure, it will not specifically limit. Among them, there are pyrrolidine, pyrrole, imidazole, pyrazole, oxazole, thiazole, piperidine, piperazine, pyridine, pyrazine, indole, benzimidazole, quinoline, isoquinoline, and carbazole, more preferably Piperazine, piperidine, indole, benzimidazole, imidazole, carbazole, pyrrole and pyridine.

Furthermore, as a specific example of Y ₂ in the formula (2), there are divalent organic groups having nitrogen atoms represented by the following formulae (YD-6) to (YD-43). The charge is accumulated and the accumulated charge is rapidly relieved, preferably formula (YD-14), (YD-18), (YD-19), (YD-20), (YD-21), (YD-23)~( YD-30) and (YD-40)~(YD-43), especially (YD-14), (YD-18), (YD-23), (YD-25) and (YD-40)~ (YD-43).

In formula (YD-17), h is an integer of 1 to 3, and in formula (YD-14), (YD-21) and (YD-22), j is an integer of 0 to 3.

In formulas (YD-25), (YD-26), (YD-29) and (YD-30), j is an integer of 0 to 3.

In the formulae (YD-41), (YD-42) and (YD-43), j is an integer of 0 to 3.

The ratio of the diamine represented by the formula (2) in the polyamic acid of the present invention and the imidized polymer of the polyamic acid is preferably 10 to 100 mol % with respect to 1 mol of all diamines , more preferably 30 to 100 mol %, still more preferably 50 to 100 mol %.

The diamine represented by the formula (2) in the polyamic acid and the imidized polymer of the component (B) of the present invention may be used alone or in combination, but in this case, the The diamine represented by the formula (2) is preferably used in the above-mentioned preferred amount as a total.

In addition to the diamine represented by the above formula (2), the following formula ( 7) The diamine represented by 7). Y ₂ in the following formula (7) is a divalent organic group, and its structure is not particularly limited, and two or more of them may be mixed. If the specific example is shown especially, the following (Y-1) - (Y-75) will be mentioned.

When the ratio of the diamine represented by the formula (7) is large in the polyamic acid and the imidized polymer of the polyamic acid as the component (B) contained in the liquid crystal aligning agent of the present invention, the And the possibility of the effect of the present invention, it is not good. Therefore, the ratio of the diamine represented by the formula (7) is preferably 0 to 90 mol %, more preferably 0 to 50 mol %, more preferably 0 to 20 mol % with respect to 1 mol % of all diamines .

<Method for producing polyamide ester> The polyamide ester of the polyimide precursor used in the present invention can be synthesized by the method (1), (2) or (3) shown below.

(1) Synthesis from polyamic acid Polyamic acid ester can be synthesized by esterifying a polyamic acid obtained from tetracarboxylic dianhydride and diamine. Specifically, in the presence of an organic solvent, the polyamide acid and the esterifying agent are reacted at -20°C to 150°C, preferably at 0°C to 50°C for 30 minutes to 24 hours, preferably 1 to 4 hours to synthesize .

The esterification agent is preferably one that can be easily removed by purification, and examples thereof include N,N-dimethylformamide dimethyl acetal, N,N-dimethylformamide diethyl acetal, N,N-dimethylformamide - Dimethylformamide dipropyl acetal, N,N-dimethylformamide di-neopentyl butyl acetal, N,N-dimethylformamide di-tert-butyl acetal, 1-Methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazene, 1-propyl-3-p-tolyltriazene, 4-(4, 6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride, etc. The addition amount of the esterifying agent is preferably 2 to 6 mol equivalents with respect to 1 mol of the repeating unit of the polyamide acid.

The solvent used in the above reaction, based on the solubility of the polymer, is preferably N,N-dimethylformamide, N-methyl-2-pyrrolidone or γ-butyrolactone, which can be 1 Use alone or in combination of two or more. The concentration at the time of synthesis is preferably from 1 to 30 mass %, more preferably from 5 to 20 mass %, from the viewpoint of hardly causing polymer precipitation and easily obtaining a high molecular weight body.

(2) Synthesis by reaction of tetracarboxylic acid diester dichloride and diamine Polyamic acid ester can be synthesized from tetracarboxylic acid diester dichloride and diamine.

Specifically, tetracarboxylic acid diester dichloride and diamine can be reacted at -20°C to 150°C, preferably 0°C to 50°C for 30 minutes to 24 hours in the presence of a base and an organic solvent, preferably at a temperature of 0°C to 50°C. 1 to 4 hours to synthesize.

As the aforementioned base, pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used, but pyridine is preferred in order to stabilize the reaction. The addition amount of the base is an amount that can be easily removed, and is preferably 2 to 4 times mol relative to the tetracarboxylic acid diester dichloride from the viewpoint of easily obtaining a high-molecular-weight body.

The solvent used in the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone based on the solubility of monomers and polymers, and these may be used alone or in combination of two or more. The polymer concentration at the time of synthesis is preferably 1 to 30 mass %, more preferably 5 to 20 mass %, from the viewpoint of hardly causing polymer precipitation and easily obtaining a high molecular weight body. In addition, in order to prevent the hydrolysis of the tetracarboxylic acid diester dichloride, the solvent used in the synthesis of the polyamic acid ester is preferably dehydrated as much as possible, and the reaction is preferably carried out in a nitrogen atmosphere to prevent the mixing of external air.

(3) In the case of synthesizing polyamic acid ester from tetracarboxylic acid diester and diamine Polyamic acid ester can be synthesized by polycondensation of tetracarboxylic acid diester and diamine.

Specifically, the tetracarboxylic acid diester and the diamine are reacted at 0°C to 150°C, preferably 0°C to 100°C for 30 minutes to 24 hours, preferably 3 ~15 hours to synthesize.

The aforementioned condensing agent can use triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, N,N '-Carbonyldiimidazole, dimethoxy-1,3,5-triazinylmethylmorpholinium, O-(benzotriazol-1-yl)-N,N,N',N'-tetra Methyluronium tetrafluoroborate, O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate, (2,3-dihydro- 2-thio-3-benzoxazolyl) diphenyl phosphonate and the like. The addition amount of the condensing agent is preferably 2 to 3 times mol relative to the tetracarboxylic acid diester.

As the aforementioned base, tertiary amines such as pyridine and triethylamine can be used. The addition amount of the alkali is an amount that can be easily removed, and from the viewpoint of easily obtaining a high molecular weight body, it is preferably 2 to 4 times mol relative to the diamine component. In addition, in the above-mentioned reaction, by adding a Lewis acid as an additive, the reaction proceeds efficiently. The Lewis acid is preferably a lithium halide such as lithium chloride or lithium bromide. The addition amount of the Lewis acid is preferably 0 to 1.0 times mol relative to the diamine component.

Among the above-mentioned three methods for synthesizing polyamic acid esters, in order to obtain a high molecular weight polyamic acid ester, the above-mentioned synthesis method (1) or the above-mentioned (2) is preferable. The solution of the polyamide obtained as described above is poured into a weak solvent with sufficient stirring, whereby the polymer can be precipitated. After several times of precipitation, washing with weak solvent, and drying at room temperature or heating, the powder of purified polyamic acid ester can be obtained. The weak solvent is not particularly limited, and examples thereof include water, methanol, ethanol, hexane, butyl cellosolve, acetone, and toluene.

<Synthesis of polyamic acid> When the specific polymer (A) or the specific polymer (B) is obtained by the reaction of tetracarboxylic dianhydride and diamine, a convenient method is to mix tetracarboxylic dianhydride with diamine in an organic solvent. A method in which diamines are mixed and reacted.

The organic solvent used in the above-mentioned reaction is not particularly limited as long as it dissolves the produced polyamide acid, and specific examples thereof include N,N-dimethylformamide, N,N-dicarbamide Methyl acetamide, N-methyl-2-pyrrolidone, N-methyl caprolactam, dimethyl sulfoxide, tetramethylurea, pyridine, dimethyl sulfoxide, hexamethyl sulfoxide, γ-Butyrolactone, etc. These may be used alone or in combination. Moreover, even if it is a solvent which does not melt|dissolve polyamic acid, in the range which does not precipitate the produced polyamic acid, it can be mixed with the said solvent and can be used. In addition, since the moisture in the organic solvent inhibits the polymerization reaction and further causes the hydrolysis of the polyamic acid produced, it is preferable to use one that dehydrates and dries the organic solvent as much as possible.

The method of mixing the tetracarboxylic dianhydride component and the diamine component in the organic solvent includes stirring to disperse or dissolve the diamine component in the organic solvent solution, directly adding or dispersing or dissolving in the organic solvent, and adding the tetracarboxylic dianhydride Conversely, the method of adding the diamine component to a solution in which the tetracarboxylic dianhydride component is dispersed or dissolved in an organic solvent, the method of alternately adding the tetracarboxylic dianhydride component and the diamine component, etc. Any of these methods can be used in the invention. In addition, when the tetracarboxylic dianhydride component or the diamine component is composed of plural kinds of compounds, these plural kinds of components may be reacted in a state of being mixed in advance, or may be reacted individually and sequentially.

The temperature at which the tetracarboxylic dianhydride component and the diamine component are reacted in an organic solvent is usually 0 to 150°C, preferably 5 to 100°C, more preferably 10 to 80°C. The higher the temperature, the faster the polymerization reaction ends, but when the temperature is too high, a polymer with a high molecular weight may not be obtained. In addition, the reaction can be carried out at any concentration, but when the concentration is too low, it is difficult to obtain a polymer with a high molecular weight, and when the concentration is too high, the viscosity of the reaction solution becomes too high and it is difficult to uniformly stir, so it is preferably 1 to 50% by weight. , more preferably 5 to 30% by weight. The initial stage of the reaction is carried out at a high concentration, and an organic solvent may be added subsequently.

The ratio of the tetracarboxylic dianhydride component to the diamine component used in the polymerization reaction of the polyamide acid is preferably 1:0.8 to 1.2 in terms of molar ratio. In addition, when the diamine component is excessive, the obtained polyamic acid may become large in solution coloration, so when the solution coloration is concerned, it is sufficient to be 1:0.8 to 1. Similar to the usual polycondensation reaction, the closer the molar ratio is to 1:1, the larger the molecular weight of the obtained polyamide acid becomes. When the molecular weight of the polyamic acid is too small, the strength of the obtained coating film may become insufficient. On the contrary, when the molecular weight of the polyamic acid is too large, the viscosity of the liquid crystal alignment treatment agent produced by them will become too high, and When the workability and the uniformity of the coating film are degraded when the coating film is formed. Therefore, the polyamide acid used in the liquid crystal alignment agent of the present invention is preferably 0.1-2.0, more preferably 0.2-1.5, in terms of reducing viscosity (concentration 0.5dl/g, 30°C in NMP).

When the liquid crystal alignment agent of the present invention does not contain the solvent used for the polymerization of polyamide, or when there are unreacted monomer components or impurities in the reaction solution, the precipitation recovery and purification are carried out. In this method, the polyamide acid solution is preferably put into a weak solvent under stirring for precipitation and recovery. The weak solvent used for the precipitation and recovery of polyamic acid is not particularly limited, and examples thereof include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, Benzene etc. The polyamide acid precipitated by putting it into a weak solvent is filtered, washed and recovered, and then dried under normal pressure or reduced pressure at room temperature or by heating to form a powder. When the powder is further dissolved in a good solvent and reprecipitated, and the repetition is repeated 2 to 10 times, the polyamic acid can also be purified. This purification step is preferably carried out when impurities cannot be removed by a single precipitation recovery operation. In this case, when three or more types of weak solvents such as alcohols, ketones, and hydrocarbons are used as the weak solvent, it is preferable because the purification efficiency can be further improved.

<Method for producing polyimide> The polyimide used in the present invention can be produced by imidizing the above-mentioned polyimide or polyimide. In the production of polyimide from polyamide, the chemical method of adding an alkaline catalyst to the above-mentioned polyamic acid ester solution or to a polyamic acid solution obtained by dissolving polyamic acid ester resin powder in an organic solvent The imidization is convenient. The chemical imidization is preferable because the imidization reaction is carried out at a relatively low temperature, and the molecular weight of the polymer is not easily reduced during the imidization process.

When producing polyimide from polyamic acid, chemical imidization in which a catalyst is added to the above-mentioned polyamic acid solution obtained by reacting a diamine component with a tetracarboxylic dianhydride is simple. The chemical imidization is preferable because the imidization reaction is carried out at a relatively low temperature, and the molecular weight of the polymer is not easily reduced during the imidization process.

Chemical imidization can be carried out by stirring the polymer to be imidized in an organic solvent in the presence of a basic catalyst and an acid anhydride. As the organic solvent, the solvent used in the aforementioned polymerization reaction can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine, and the like. Among them, pyridine is preferred because it has a moderate basicity for the reaction to proceed. In addition, acetic anhydride, trimellitic anhydride, pyromellitic anhydride, etc. are mentioned as an acid anhydride, and it is preferable to use acetic anhydride because purification after completion|finish of reaction becomes easy.

The temperature at the time of carrying out the imidization reaction is -20°C to 140°C, preferably 0°C to 100°C, and the reaction time can be carried out for 1 to 100 hours. The amount of the alkaline catalyst is 0.5~30 mole times, preferably 2~20 mole times, of the amide acid group, and the amount of the acid anhydride is 1~50 mole times the amide acid group, preferably 3~20 mole times. 30 mole times. The imidization rate of the obtained polymer can be controlled by adjusting the catalyst amount, temperature and reaction time.

Since the added catalyst and the like remain in the solution after the imidization reaction of the polyamic acid ester or polyamic acid, it is preferable to recover the obtained imidized polymer by the following means, and use an organic solvent Re-dissolved, used as the liquid crystal alignment agent of the present invention.

The polyimide solution obtained as described above is poured into a weak solvent while stirring well, whereby a polymer can be precipitated. After several precipitations, washing with weak solvent, and drying at room temperature or heating, purified polyamide powder can be obtained. The aforementioned weak solvent is not particularly limited, and examples thereof include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, and benzene.

The molecular weights of the polyimide precursors of the components (A) and (B) used in the present invention are, in terms of weight average molecular weight, preferably 2,000 to 500,000, more preferably 5,000 to 300,000, still more preferably 10,000 to 100,000 .

The polyimide of (A) component and (B) component used for this invention is the polyimide obtained by ring-closing the said polyimide precursor. In the polyimide, the ring closure ratio of the amide acid group (also referred to as the amide imidization ratio) does not necessarily have to be 100%, and may be adjusted arbitrarily according to the application or purpose.

<Liquid crystal alignment agent> The liquid crystal alignment agent of the present invention is a composition for forming a liquid crystal alignment film, and contains a specific polymer (A) having the structure represented by the above formula (1) and a specific polymer (A) containing the structure represented by the above formula (2). As for the polymer (B), each of the specific polymer (A) and the specific polymer (B) contained in the liquid crystal aligning agent of the present invention may be one type or two or more types. In addition to the specific polymer, another polymer, that is, a polymer having neither the divalent group represented by the formula (1) nor the divalent group represented by the formula (2) may be contained. Examples of such other polymers include polyamides, polyimides, polyamides, polyesters, polyamides, polyureas, polyorganosiloxanes, cellulose derivatives, polycondensates Aldehyde, polystyrene or its derivatives, poly(styrene-phenylmaleimide) derivatives, poly(meth)acrylates, and the like. When the liquid crystal aligning agent of this invention contains another polymer, the specific polymer ratio which accounts for all polymer components is preferably 5 mass % or more, and 5-95 mass % is mentioned as an example.

The liquid crystal aligning agent is used for producing a liquid crystal aligning film, and is generally used in the form of a coating liquid from the viewpoint of forming a uniform thin film. In the liquid crystal aligning agent of this invention, the coating liquid containing the said polymer component and the organic solvent which melt|dissolves this polymer component is also preferable. At this time, the polymer concentration in the liquid crystal aligning agent can be appropriately changed according to the setting of the thickness of the coating film to be formed. From the viewpoint of forming a uniform and defect-free coating film, it is preferably at least 1 mass %, and from the viewpoint of the storage stability of the solution, it is preferably at most 10 mass %. A particularly preferred polymer concentration is 2 to 8% by mass.

The organic solvent contained in the liquid crystal aligning agent is not particularly limited as long as it can uniformly dissolve the polymer components. Specific examples thereof include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2- Pyrrolidone, dimethylsulfoxide, γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, etc. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ-butyrolactone is preferably used.

In addition, the organic solvent contained in the liquid crystal aligning agent, in addition to the above-mentioned solvents, is generally used in combination with a solvent that improves the coating properties of the liquid crystal aligning agent or the surface smoothness of the coating film. In the liquid crystal aligning agent of the present invention It is also preferable to use such a mixed solvent. Specific examples of the organic solvent used in combination are as follows, but are not limited to these examples.

For example, ethanol, isopropanol, 1-butanol, 2-butanol, isobutanol, 3-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1 -Butanol, isoamyl alcohol, tertiary amyl alcohol, 3-methyl-2-butanol, neopentanol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol Alcohol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, cyclohexanol , 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 2,6-dimethyl-4-heptanol, 1,2-ethylene glycol, 1,2- Propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2- Methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, diisopropyl ether, dipropyl ether, dibutyl ether, dihexyl ether, dioxane, ethylenediol Alcohol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-Hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 2-pentanone, 3-pentanone, 2-hexanone, 2- Heptanone, 4-heptanone, 2,6-dimethyl-4-heptanone, 4,6-dimethyl-2-heptanone, 3-ethoxybutyl acetate, 1-methylpentyl acetate , 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, 2-(methoxymethyl) oxy)ethanol, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, 2-(hexyloxy)ethanol, furfuryl alcohol, diethylene glycol, propylene glycol, diethylene glycol Alcohol monoethyl ether, diethylene glycol monomethyl ether, propylene glycol monobutyl ether, 1-(butoxyethoxy) propanol, propylene glycol monomethyl ether acetate, dipropylene glycol, dipropylene glycol monomethyl ether Ethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono Butyl ether acetate, ethylene glycol monoacetate, ethylene glycol diacetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, acetic acid 2- (2-ethoxyethoxy) ethyl ester, diethylene glycol acetate, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, methyl lactate, ethyl lactate Ester, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate ester, methyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, 3- Butyl methoxypropionate, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, solvents represented by the following formulae [D-1] to [D-3], and the like.

In formula [D-1], D ¹ represents an alkyl group with 1 to 3 carbon atoms, in formula [D-2], D ² represents an alkyl group with 1 to 3 carbon atoms, and in formula [D-3], D ³ Represents an alkyl group having 1 to 4 carbon atoms.

Among them, the preferred solvent combinations include N-methyl-2-pyrrolidone and γ-butyrolactone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and Propylene glycol monobutyl ether, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and 4-hydroxy-4-methyl-2 -Pentanone and diethylene glycol diethyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether and 2,6-dimethyl-4-heptanone, N -Methyl-2-pyrrolidone with γ-butyrolactone and propylene glycol monobutyl ether with diisopropyl ether, N-methyl-2-pyrrolidone with γ-butyrolactone and propylene glycol monobutyl ether with 2,6-dimethyl-4-heptanol, N-methyl-2-pyrrolidone, γ-butyrolactone and dipropylene glycol dimethyl ether, etc. The type and content of such a solvent are appropriately selected according to the coating apparatus of the liquid crystal alignment agent, coating conditions, coating environment, and the like.

In addition, in the liquid crystal aligning agent of the present invention, in order to improve the adhesion of the coating film to the substrate, a silane coupling agent may be added, and other resin components may also be added.

As a compound for improving the adhesion between the liquid crystal alignment film and the substrate, a functional silane compound or an epoxy group-containing compound is exemplified, for example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethyl Oxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-amine propyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl) yl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-amino Propyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyl Triethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, acetic acid 9-Trimethoxysilyl-3,6-diazanonyl ester, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropane Trimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyl Triethoxysilane, N-bis(oxyethylidene)-3-aminopropyltrimethoxysilane, N-bis(oxyethylidene)-3-aminopropyltriethoxysilane, ethyl Glycol Diglycidyl Ether, Polyethylene Glycol Diglycidyl Ether, Propylene Glycol Diglycidyl Ether, Tripropylene Glycol Diglycidyl Ether, Polypropylene Glycol Diglycidyl Ether, Neopentyl Glycol Diglycidyl Ether, 1,6-Hexane Glycol diglycidyl ether, glycerol diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol , N,N,N',N'-tetraglycidyl-m-xylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane or N,N, N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, etc.

Moreover, in the liquid crystal aligning agent of this invention, you may add the following additives to improve the mechanical strength of a film.

These additives are preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent. If it is less than 0.1 parts by mass, the effect cannot be expected, and when it exceeds 30 parts by mass, since the liquid crystal orientation is lowered, it is more preferably 0.5 to 20 parts by mass.

<Liquid crystal alignment film> The liquid crystal alignment film of the present invention is obtained from the aforementioned liquid crystal alignment agent. An example of a method for obtaining a liquid crystal alignment film from a liquid crystal alignment agent is to apply a liquid crystal alignment agent in the form of a coating solution to a substrate, dry and bake the resulting film by a rubbing treatment method or a photo-alignment treatment method. A method of implementing alignment processing.

The substrate on which the liquid crystal alignment agent is coated is not particularly limited as long as it is a substrate with high transparency, and glass substrates, silicon nitride substrates, and plastic substrates such as acrylic substrates and polycarbonate substrates can be used. At this time, it is preferable from the viewpoint of process simplification when using the board|substrate which formed the ITO electrode etc. for driving a liquid crystal. In addition, if the reflective liquid crystal display element is a substrate with only one side, an opaque material such as a silicon wafer may be used, and a material such as aluminum that reflects light may also be used for the electrode in this case.

The coating method of the liquid crystal aligning agent is not particularly limited, and industrially, it is generally a screen printing method, a gravure printing method, a flexographic printing method, an inkjet method, and the like. As another coating method, there exist a dip method, a roll coater method, a slit coater method, a spin coater method, a spray method, etc., and these can be used according to the objective.

After the liquid crystal alignment treatment agent is applied on the substrate, the solvent can be evaporated and fired by heating means such as a hot plate, a thermal cycle oven, and an IR (infrared) oven. The drying and firing steps after coating the liquid crystal alignment agent can choose any temperature and time. Usually, in order to fully remove the contained solvent, the conditions of baking at 50-120 degreeC for 1 to 10 minutes, and then baking at 150-300 degreeC for 5-120 minutes are mentioned.

Although the film thickness of the liquid crystal alignment film after firing is not particularly limited, if it is too thin, the reliability of the liquid crystal display element may decrease, so it is preferably 5 to 300 nm, more preferably 10 to 200 nm. The liquid crystal alignment film of the present invention is preferably used as a liquid crystal alignment film for a liquid crystal display element of a lateral electric field method such as an IPS method or an FFS method, and is particularly useful as a liquid crystal alignment film for a liquid crystal display element of the FFS method.

<Liquid crystal display element> The liquid crystal display element of the present invention is obtained by obtaining a substrate with a liquid crystal alignment film obtained from the above-mentioned liquid crystal alignment agent, and then producing a liquid crystal cell by a known method, and using the liquid crystal cell as an element. An example of a method of manufacturing a liquid crystal cell is described by taking a liquid crystal display element with a passive matrix structure as an example. Moreover, the liquid crystal display element of an active matrix structure in which switching elements, such as a TFT (Thin Film Transistor), are provided in each pixel part which comprises an image display may be sufficient.

Specifically, substrates made of transparent glass are prepared, common electrodes are provided on one substrate, and segment electrodes are provided on the other substrate. The electrodes can be, for example, ITO electrodes and patterned in such a way that the desired image display can be performed. Next, an insulating film is provided on each substrate so as to cover the common electrode and the segment electrode. The insulating film may be a film made of SiO ₂ -TiO ₂ formed by a sol-gel method. Next, a liquid crystal alignment film is formed on each substrate under the conditions described above.

Next, arrange a UV-curable sealing material on a specific part of one of the two substrates on which the liquid crystal alignment film is formed, and then arrange liquid crystals on a specific number of places on the surface of the liquid crystal alignment film, and then use the liquid crystal alignment film to face each other. After attaching to another substrate by pressing and pushing the liquid crystal in front of the liquid crystal alignment film, the entire substrate is irradiated with ultraviolet rays to harden the sealing material to obtain a liquid crystal cell.

In addition, as a step after forming a liquid crystal alignment film on a substrate, when disposing a sealing material at a specific position on a substrate, an opening portion that can be filled with liquid crystal from the outside is provided in advance, and after the substrate is bonded without disposing liquid crystal, it is installed on the substrate. In the opening of the sealing material, a liquid crystal material is injected into the liquid crystal cell, and then the opening is sealed with an adhesive to obtain a liquid crystal cell. The injection of the liquid crystal material may be a vacuum injection method or a method using capillary phenomenon in the atmosphere.

In any of the above methods, in order to ensure the space for filling the liquid crystal material in the liquid crystal cell, it is preferable to set columnar protrusions on a substrate, or spread spacers on a substrate, or mix spacers in the sealing material, or the A combination of equals and other means.

As said liquid crystal material, a nematic liquid crystal and a smectic liquid crystal are mentioned, Of these, a nematic liquid crystal is preferable, and either a positive liquid crystal material or a negative liquid crystal material may be used. Next, configure the polarizer. Specifically, a pair of polarizing plates is preferably attached to the surface of the two substrates on the opposite side to the liquid crystal layer. In addition, the liquid crystal alignment film and the liquid crystal display element of the present invention are not limited to the above description as long as the liquid crystal alignment agent of the present invention is used, and other conventional methods may also be used. The steps from a liquid crystal aligning agent to obtaining a liquid crystal display element are disclosed in, for example, paragraphs 0074 to 19 of paragraphs 0074 to 19 of Japanese Patent Laid-Open No. 2015-135393.

<Method for producing a substrate with a liquid crystal alignment film> and <Method for producing a liquid crystal display element> As an example of a method for producing a substrate having a liquid crystal alignment film of the present invention, a liquid crystal alignment film for a lateral electric field driven liquid crystal display element is shown below manufacturing method. It has the following steps: [1] After coating a liquid crystal alignment agent on a substrate with a conductive film for transverse electric field driving, and drying it to form a coating film, the liquid crystal alignment agent contains: a polymer (A), which At least one selected from the group consisting of a polyamic acid obtained by using a tetracarboxylic dianhydride component and a diamine component containing the diamine represented by the above formula (1), and an imidized polymer of the polyamic acid; and A polymer (B) obtained from a polyamic acid obtained by using a tetracarboxylic dianhydride component and a diamine component containing the diamine represented by the above formula (2), and an imidized polymer of the polyamic acid At least one selected from among the following; [II] a step of irradiating the coating film obtained by [I] with polarized ultraviolet rays; and [III] a step of heating the coating film obtained by [II]; A liquid crystal alignment film for a lateral electric field driven liquid crystal display element with controlled energy can be used to obtain a substrate having the liquid crystal alignment film.

Furthermore, by preparing a second substrate in addition to the substrate (first substrate) obtained above, a lateral electric field drive type liquid crystal display element can be obtained. The second substrate is made by using the above steps [I] to [III] (due to the use of the above-mentioned steps [I] to [III], except that the substrate having the conductive film for horizontal electric field driving is used instead of the substrate having the conductive film for transverse electric field driving. For the sake of convenience, it is sometimes referred to as steps [I']~[III']) for electric field driving, and a second liquid crystal alignment film having a liquid crystal alignment film imparted with alignment control energy can be obtained. substrate.

The manufacturing method of the horizontal electric field driving type liquid crystal display element has [IV] The liquid crystal display is obtained by arranging the first and second substrates obtained as described above to face each other so that the liquid crystal alignment films of the first and second substrates are opposed to each other through liquid crystals. component steps. In this way, a lateral electric field-driven liquid crystal display element can be obtained.

Hereinafter, each step of [I] to [III] and [IV] included in the production method of the present invention will be described.

<Step [I]> In step [I], a polymer composition containing a photosensitive main chain type polymer and an organic solvent is coated on a substrate having a conductive film for transverse electric field driving, and then dried to form a coating film . The photosensitive main chain type polymer in this invention is a specific polymer (A).

<Substrate> The substrate is not particularly limited, but when the liquid crystal display element to be manufactured is a transmissive type, a substrate with high transparency is preferably used. In this case, it is not particularly limited, and a glass substrate, or a plastic substrate such as an acrylic substrate or a polycarbonate substrate can be used. Furthermore, considering the applicability to reflective liquid crystal display elements, opaque substrates such as silicon wafers can be used.

<Conductive film for transverse electric field driving> The substrate has a conductive film for transverse electric field driving. As the conductive film, when the liquid crystal display element is of a transmission type, ITO (Indium Tin Oxide: Indium Tin Oxide), IZO (Indium Zinc Oxide: Indium Zinc Oxide), etc. are mentioned, but not limited to these. In addition, in the case of a reactive liquid crystal display element, as the conductive film, materials that can reflect light, such as aluminum, can be mentioned, but are not limited to these. As the method of forming the conductive film on the substrate, a conventionally known method can be used.

The method of coating the above-mentioned polymer composition on the substrate having the conductive film for driving the transverse electric field is not particularly limited. The coating method is generally carried out by screen printing, offset printing, flexographic printing or inkjet method in the industry. As another coating method, there are dipping method, roll coating method, slit coating method, spin coating method (spin coating method), spray method, etc., and these can be used according to the purpose.

After coating the polymer composition on the substrate with the conductive film for horizontal electric field driving, it is heated at 30~150℃, preferably 70℃ by heating means such as a hot plate, a thermal cycle oven or an IR (infrared) type oven. A coating film can be obtained by evaporating the solvent at ~110°C. When the drying temperature is too low, the drying of the solvent tends to be insufficient, and when the heating temperature is too high, thermal imidization is performed, and the photolysis reaction is excessively advanced by polarized light exposure. Realignment in one direction caused by self-organization is detrimental to the stability of the alignment. Therefore, the drying temperature at this time is preferably a temperature at which thermal imidization of the specific polymer does not substantially proceed from the viewpoint of the stability of liquid crystal alignment. When the thickness of the coating film is too thick, the power consumption of the liquid crystal display element becomes unfavorable, and when it is too thin, the reliability of the liquid crystal display element may decrease, so it is preferably 5nm~300nm, more preferably 10nm~150nm. In addition, after step [I] and before step [II], a step of cooling the substrate on which the coating film is formed may be provided to room temperature.

<Step [II]> The step [II] is to irradiate the coating film obtained in the step [I] with polarized ultraviolet rays. When irradiating polarized ultraviolet rays to the film surface of the coating film, the polarized ultraviolet rays are irradiated to the substrate from a certain direction through a polarizing plate. As the ultraviolet rays to be used, ultraviolet rays with wavelengths ranging from 100 nm to 400 nm can be used. Preferably, the most appropriate wavelength is selected according to the type of coating film to be used, the isolation filter, and the like. Furthermore, for example, ultraviolet rays having a wavelength in the range of 240 nm to 400 nm can be selectively used so that a photolysis reaction can be selectively induced. As the ultraviolet rays, light emitted from, for example, high-pressure mercury lamps or metal halide lamps can be used.

The exposure of polarized ultraviolet rays is related to the coating film used. The irradiation dose is preferably set to the amount of polarized ultraviolet rays that achieves the difference between the ultraviolet absorbance in the direction parallel to the polarization direction of the polarized ultraviolet rays and the ultraviolet absorbance in the perpendicular direction, that is, the maximum value of ΔA (hereinafter also referred to as ΔAmax) in the coating film. Within the range of 1% to 70%, preferably within the range of 1% to 50%.

<Step [III]> Step [III] is to heat the coating film irradiated with polarized ultraviolet rays in step [II]. By heating, an alignment control function can be imparted to the coating film. For heating, heating means such as a hot plate, thermal cycle oven or IR (infrared) oven can be used. The heating temperature can be determined in consideration of the temperature at which the coating film used exhibits the stability of liquid crystal alignment and electrical properties.

The heating temperature is preferably within a temperature range in which the main chain type polymer exhibits good liquid crystal alignment stability. When the heating temperature is too low, the anisotropy amplification effect or thermal imidization by heat tends to be insufficient, and when the heating temperature is too high, the imparting effect by polarized light exposure may be caused. The anisotropy tends to disappear, and in this case, it may be difficult to realign in one direction by self-organization.

The thickness of the coating film formed after heating is preferably from 5 nm to 300 nm, more preferably from 50 nm to 150 nm, for the same reason as described in the step [I].

By having the above steps, the production method of the present invention can efficiently introduce anisotropy into the coating film. Furthermore, a substrate with a liquid crystal alignment film can be efficiently produced.

<Step [IV]> The step [IV] is to make the substrate (first substrate) having a liquid crystal alignment film on the conductive film for transverse electric field driving obtained in [III] as in the above [I'] to [III'] The obtained substrate with a liquid crystal alignment film (second substrate) without a conductive film is disposed opposite to each other with the two liquid crystal alignment films facing each other across the liquid crystal, a liquid crystal cell is produced by a conventional method, and a transverse electric field is produced The steps of driving a liquid crystal display element. In addition, the steps [I'] to [III'] can be performed in the same manner as the step [I], except that the substrate having the conductive film for transverse electric field driving is used instead of the substrate having the conductive film for transverse electric field driving. I] to [III] are carried out in the same manner. The difference between steps [I]~[III] and [I']~[III'] is only the presence or absence of the above-mentioned conductive film, so the description of steps [I']~[III'] is omitted.

If an example of liquid crystal cell or liquid crystal display element production is given, the above-mentioned first and second substrates are prepared, spacers are scattered on the liquid crystal alignment film of one substrate, and the liquid crystal alignment film surface is attached to the inner side. Another substrate, the method of injecting liquid crystal under reduced pressure and sealing, or the method of dropping liquid crystal on the surface of the liquid crystal alignment film scattered with spacers, and then laminating the substrate and sealing. In this case, as the one-side substrate, it is preferable to use a substrate having electrodes having a structure such as comb teeth for driving the transverse electric field. In this case, the diameter of the spacer is preferably from 1 μm to 30 μm, more preferably from 2 μm to 10 μm. The diameter of the spacer will determine the distance between a pair of substrates sandwiching the liquid crystal layer, that is, the thickness of the liquid crystal layer.

The manufacturing method of the coated substrate of the present invention is to apply a polymer composition on the substrate to form a coating film, and then irradiate polarized ultraviolet rays. Next, anisotropy can be efficiently introduced into the main chain type polymer film by heating, and a liquid crystal alignment film-attached substrate having the alignment control ability of liquid crystal is produced. The coating film used in the present invention utilizes the principle of molecular realignment induced by self-organization based on the photoreaction of the main chain, so as to efficiently introduce anisotropy into the coating film. In the production method of the present invention, when the main chain type polymer has a structure in which a photodecomposable group is used as a photoreactive group, the main chain type polymer is used to form a coating film on a substrate, then irradiated with polarized ultraviolet rays, followed by heating Then the liquid crystal display element is produced.

Therefore, the coating film used in the method of the present invention can efficiently introduce anisotropy by sequentially irradiating the coating film with polarized ultraviolet rays and heat treatment, and can become a liquid crystal alignment film with excellent alignment control.

Therefore, in the coating film used in the method of the present invention, the irradiation amount of the polarized ultraviolet rays to the coating film and the heating temperature in the heat treatment are optimized. Thereby, anisotropy can be efficiently introduced into the coating film.

The irradiation dose of the optimum polarized ultraviolet rays for efficiently introducing anisotropy into the coating film used in the present invention corresponds to the irradiation dose of polarized ultraviolet rays which is optimized for the photodecomposition reaction of the photosensitive groups in the coating film. As a result of irradiating polarized ultraviolet rays to the coating film used in the present invention, when there are few photosensitive groups for photodecomposition reaction, a sufficient photoreaction amount is not obtained. In this case, sufficient self-organization does not proceed even after heating.

Therefore, in the coating film used in the present invention, the optimum amount of photodecomposition reaction of the photosensitive group by the irradiation of polarized ultraviolet rays is preferably 0.1 mol % to 90 mol % of the polymer film, more preferably 0.1 mol %. Molar% ~ 80 Molar%. By setting the quantity of the photosensitive group of the photoreaction to such a range, the self-organization efficiency in the subsequent heat treatment can be efficiently performed, and anisotropy can be efficiently formed in the film.

The coating film used in the method of the present invention optimizes the amount of photodecomposition reaction of photosensitive groups in the main chain of the polymer film by optimizing the amount of polarized ultraviolet radiation. Therefore, together with the subsequent heat treatment, it is possible to efficiently introduce anisotropy into the coating film used in the present invention. In this case, the amount of preferable polarized ultraviolet rays can be evaluated based on the ultraviolet absorption evaluation of the coating film used in the present invention.

That is, with respect to the coating film used in the present invention, the ultraviolet absorption in the direction parallel to the polarization direction of the polarized ultraviolet rays and the ultraviolet absorption in the perpendicular direction were measured respectively after irradiation with polarized ultraviolet rays. From the measurement results of the ultraviolet absorption, the difference between the ultraviolet absorbance in the direction parallel to the polarization direction of the polarized ultraviolet rays and the ultraviolet absorbance in the perpendicular direction in the coating film was evaluated as ΔA. Next, the maximum value (ΔAmax) of ΔA achieved in the coating film used in the present invention and the irradiation amount of polarized ultraviolet rays to achieve the same were obtained. In the manufacturing method of the present invention, based on the amount of polarized ultraviolet radiation that achieves ΔAmax, the preferred amount of polarized ultraviolet radiation to be irradiated in the manufacture of the liquid crystal alignment film can be determined.

From the above, since the production method of the present invention can efficiently introduce anisotropy into the coating film, the preferred heating temperature can be determined based on the temperature range in which the main chain type polymer imparts alignment stability to the liquid crystal. . Therefore, for example, the temperature range in which the main-chain polymer used in the present invention imparts alignment stability to liquid crystal can be determined in consideration of the temperature at which the coating film used exhibits good liquid crystal alignment stability and electrical properties. The temperature range of the liquid crystal alignment film made of amine or the like is set. That is, the heating temperature after polarized ultraviolet irradiation is preferably 150°C to 300°C, and more desirably 180°C to 250°C. In this way, a larger anisotropy can be imparted to the coating film used in the present invention.

In this way, the liquid crystal display element provided by the present invention exhibits high reliability against external stress such as light or heat.

As described above, the substrate for a lateral electric field driven liquid crystal display element produced by using the polymer of the present invention or a lateral electric field driven liquid crystal display element having the same is excellent in reliability, and can be preferably used for a large screen and high Sophisticated LCD TV. Moreover, since the liquid crystal alignment film produced by the method of the present invention has excellent liquid crystal alignment stability and reliability, it can also be used in a variable phase device using liquid crystal, and the variable phase device can be preferably used for, for example, resonant frequency Variable antenna, etc. [Example]

Hereinafter, although an Example etc. are given and demonstrated concretely about this invention, this invention is not limited to these Examples. In addition, the abbreviations of compounds and solvents are as follows. NMP: N-methyl-2-pyrrolidone BCS: butyl cellosolve DA-1: Compound represented by the following structural formula (DA-1) DA-2: Compound DA represented by the following structural formula (DA-2) -3: Compound DA-4 represented by the following structural formula (DA-3): Compound DA-5 represented by the following structural formula (DA-4): Compound DA-6 represented by the following structural formula (DA-5) : Compound DA-7 represented by the following structural formula (DA-6): Compound DA-8 represented by the following structural formula (DA-7): Compound CA-1 represented by the following structural formula (DA-8): The following The compound CA-2 represented by the structural formula (CA-1): the compound represented by the following structural formula (CA-2) CA-3: the compound represented by the following structural formula (CA-3)

<Measurement of Viscosity> In the synthesis example, the viscosity of the polymer solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.), a sample volume of 1.1 mL, and a conical rotor TE-1 (1°34', R24) , measured at a temperature of 25°C.

<Synthesis Example 1> 3.91 g (13.0 mmol) of DA-1 was weighed into a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, 25.7 g of NMP was added, and the mixture was dissolved while stirring while blowing in nitrogen gas. While stirring the diamine solution under ice-cooling, 1.76 g (8.97 mmol) of CA-1 was added, and after stirring at 23° C. for 3 hours under a nitrogen atmosphere, 0.81 g (3.25 mmol) of CA-2 was added, followed by NMP. 11.0 g was stirred at 50° C. for 20 hours under a nitrogen atmosphere to obtain a polyamic acid solution. The viscosity of the polyamide acid solution at a temperature of 25°C is 571mPa. s.

12.1 g of the polyamic acid solution was taken into a 100 mL conical flask with a stirring bar, 16.1 g of NMP and 12.1 g of BCS were added, and the mixture was stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (PAA-1).

<Synthesis Example 2> In a 100 mL four-neck flask equipped with a stirring device and a nitrogen introduction tube, 2.79 g (14.0 mmol) of DA-2 and 1.47 g (6.00 mmol) of DA-3 were weighed, and 50.5 g of NMP was added. The mixture was dissolved by stirring while blowing in nitrogen. While stirring the diamine solution under ice-cooling, 5.59 g (19.0 mmol) of CA-3 was added, and 21.7 g of NMP was further added, and the mixture was stirred at 50° C. for 20 hours under a nitrogen atmosphere to obtain a polyamide acid solution. The viscosity of the polyamide acid solution at a temperature of 25°C is 480mPa. s.

14.5 g of the polyamide acid solution was collected in a 100 mL conical flask with a stirring bar, 12.6 g of NMP and 11.6 g of BCS were added, and the mixture was stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (PAA-2).

<Synthesis Example 3> 1.59 g (8.00 mmol) of DA-2 and 0.40 g (2.00 mmol) of DA-4 were weighed into a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, and 24.0 g of NMP was added. The mixture was dissolved by stirring while blowing in nitrogen. While stirring the diamine solution under ice-cooling, 1.81 g (9.25 mmol) of CA-1 was added, and 10.3 g of NMP was further added, and the mixture was stirred at 23° C. for 4 hours under a nitrogen atmosphere to obtain a polyamic acid solution. The viscosity of the polyamide acid solution at a temperature of 25°C is 134mPa. s.

17.7 g of the polyamide acid solution was collected in a 100 mL conical flask with a stirring bar, 9.83 g of NMP and 11.8 g of BCS were added, and the mixture was stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (PAA-3).

<Synthesis Example 4> 1.49 g (7.00 mmol) of DA-5 and 0.73 g (3.00 mmol) of DA-3 were weighed into a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, and 25.8 g of NMP was added. The mixture was dissolved by stirring while blowing in nitrogen. While stirring the diamine solution under ice-cooling, 2.80 g (9.50 mmol) of CA-3 was added, and 11.0 g of NMP was further added, and the mixture was stirred at 50° C. under a nitrogen atmosphere for 20 hours to obtain a polyamide acid solution. The viscosity of the polyamide acid solution at a temperature of 25°C is 432mPa. s.

14.7 g of the polyamide acid solution was collected in a 100 mL conical flask with a stirring bar, 12.7 g of NMP and 11.8 g of BCS were added, and the mixture was stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (PAA-4).

<Synthesis Example 5> 0.80 g (4.0 mmol) of DA-2, 0.73 g (3.00 mmol) of DA-3, and 1.18 g (3.00 mmol) of DA-3 were weighed into a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube. ) of DA-6, 28.3 g of NMP was added, and it was dissolved by stirring while blowing in nitrogen. While stirring the diamine solution under ice cooling, 2.80 g (9.50 mmol) of CA-3 was added, and 12.1 g of NMP was further added, and the mixture was stirred at 50° C. under a nitrogen atmosphere for 20 hours to obtain a polyamide acid solution. The viscosity of the polyamide acid solution at a temperature of 25°C is 512mPa. s.

14.5 g of the polyamide acid solution was collected in a 100 mL conical flask with a stirring bar, 12.6 g of NMP and 11.6 g of BCS were added, and the mixture was stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (PAA-5).

<Comparative Synthesis Example 1> In a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, 3.54 g (13.0 mmol) of DA-7 was weighed, 24.2 g of NMP was added, and the mixture was stirred and dissolved while blowing in nitrogen gas. While stirring the diamine solution under ice-cooling, 1.76 g (8.97 mmol) of CA-1 was added, and after stirring at 23° C. for 3 hours under a nitrogen atmosphere, 0.81 g (3.25 mmol) of CA-2 was added, followed by NMP. 10.4 g was stirred at 50° C. for 20 hours under a nitrogen atmosphere to obtain a polyamic acid solution. The viscosity of the polyamide acid solution at a temperature of 25°C is 627mPa. s.

11.9 g of the polyamic acid solution was collected in a 100 mL conical flask with a stirring bar, 15.9 g of NMP and 11.9 g of BCS were added, and the mixture was stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (PAA-a).

<Comparative Synthesis Example 2> 4.27 g (13.0 mmol) of DA-8 was weighed into a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, 27.1 g of NMP was added, and the mixture was stirred and dissolved while blowing in nitrogen gas. While stirring the diamine solution under ice-cooling, 1.76 g (8.97 mmol) of CA-1 was added, and after stirring at 23° C. for 3 hours under a nitrogen atmosphere, 0.81 g (3.25 mmol) of CA-2 was added, followed by NMP. 11.6 g was stirred at 50° C. for 20 hours under a nitrogen atmosphere to obtain a polyamic acid solution. The viscosity of the polyamide acid solution at a temperature of 25°C is 483mPa. s.

12.2 g of the polyamide acid solution was collected in a 100 mL conical flask with a stirring bar, 16.3 g of NMP and 12.2 g of BCS were added, and the mixture was stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (PAA-b).

<Example 1> 4.03 g of the polyimide solution (PAA-1) obtained in Synthesis Example 1 and 6.05 g of the polyimide solution obtained in Synthesis Example 2 were weighed into a 50 mL conical flask with a stirring bar. (PAA-2) was stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal aligning agent (A-1).

<Example 2> 4.01 g of the polyimide solution (PAA-1) obtained in Synthesis Example 1 and 6.02 g of the polyimide solution obtained in Synthesis Example 3 were weighed into a 50 mL conical flask with a stirring bar. (PAA-3) was stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal aligning agent (A-2).

<Example 3> 4.04 g of the polyimide solution (PAA-1) obtained in Synthesis Example 1 and 6.07 g of the polyimide solution obtained in Synthesis Example 4 were weighed into a 50 mL conical flask with a stirring bar. (PAA-4) was stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal aligning agent (A-3).

<Example 4> 4.03 g of the polyimide solution (PAA-1) obtained in Synthesis Example 1 and 6.04 g of the polyimide solution obtained in Synthesis Example 5 were weighed into a 50 mL conical flask with a stirring bar. (PAA-5) was stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal aligning agent (A-4).

<Comparative Example 1> The polyimide solution (PAA-1) obtained in Synthesis Example 1 was used as a liquid crystal aligning agent (B-1).

<Comparative Example 2> In a 50 mL conical flask placed in a stirring bar, 4.03 g of the polyimide solution (PAA-a) obtained in Comparative Synthesis Example 1 and 6.05 g of the polyimide obtained in Synthesis Example 2 were weighed The solution (PAA-2) was stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (B-2).

<Comparative Example 3> In a 50 mL Erlenmeyer flask placed in a stirring bar, weigh 4.00 g of the polyimide solution (PAA-b) obtained in Comparative Synthesis Example 2 and 6.00 g of the polyimide obtained in Synthesis Example 2. The solution (PAA-2) was stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal aligning agent (B-3).

<Preparation of liquid crystal cells for evaluation of liquid crystal alignment properties and accumulated charge relaxation properties> Hereinafter, a method for preparing liquid crystal cells for evaluating liquid crystal alignment properties and accumulated charge relaxation properties will be shown. Manufactured a liquid crystal cell with the structure of a liquid crystal display element of the FFS method. First, prepare the substrate with electrodes. The substrate is a glass substrate with a size of 30mm×35mm and a thickness of 0.7mm. The IZO electrode constituting the counter electrode as the first layer was formed on the entire surface of the substrate. On the opposite electrode of the first layer, a SiN (silicon nitride) film formed by the CVD method as the second layer is formed. The SiN film of the second layer has a film thickness of 500 nm and functions as an interlayer insulating film. On the SiN film of the second layer, a comb-shaped pixel electrode formed by patterning the IZO film as the third layer was disposed to form two pixels of a first pixel and a second pixel. The size of each pixel is 10mm in length and 5mm in width. At this time, the counter electrode of the first layer and the pixel electrode of the third layer are electrically insulated by the function of the SiN film of the second layer.

The pixel electrode of the third layer is the same as the figure described in Japanese Patent Laid-Open No. 2014-77845 (Japanese Laid-Open Patent Publication), and has a comb-like shape in which a plurality of electrode elements with a curved center portion are arranged in a zigzag shape. The width of each electrode element in the short-side direction was 3 μm, and the interval between the electrode elements was 6 μm. The pixel electrodes that form each pixel are formed by arranging a plurality of electrode elements in the shape of a letter with a curved center portion, so that the shape of each pixel is not a rectangular shape, but has a similar shape of a bold letter with a curved center portion similar to the electrode element. shape of the word. Further, each pixel is divided into upper and lower parts with the curved portion at the center as a boundary, and has a first area on the upper side of the curved portion and a second area on the lower side.

When comparing the first region and the second region of each pixel, the direction in which the electrode elements constituting the pixel electrodes are formed is different. That is, when the polarization plane of the polarized ultraviolet light described later is projected on the line segment direction of the substrate, the electrode element formed as the pixel electrode in the first region of the pixel is at an angle of +10° (clockwise), and the second pixel in the pixel. The area is formed so that the electrode element of the pixel electrode forms an angle of -10° (clockwise). That is, in the first region and the second region of each pixel, the directions of the liquid crystal rotation (plane switching) in the substrate plane induced by the voltage application between the pixel electrode and the counter electrode are opposite to each other. .

Next, the liquid crystal alignment agents obtained in Examples 1 to 4 and Comparative Examples 1 to 3 were filtered with a 1.0 μm filter, and then coated on the prepared substrate with electrodes by spin coating. Next, it was dried on a hot plate set at 70°C for 90 seconds. Next, an exposure device: APL-L050121S1S-APW01 manufactured by USHIO Electric Co., Ltd. was used to irradiate linearly polarized light of ultraviolet rays through a wavelength selective filter and a polarizing plate from a direction perpendicular to the substrate. At this time, the direction of the polarization plane was set so that the direction of the line segment in which the plane of polarization of the polarized ultraviolet rays was projected on the substrate was inclined by 10° with respect to the IZO comb-shaped electrode of the third layer. Next, it baked for 30 minutes in the IR (infrared) type oven set to 230 degreeC, and obtained the board|substrate with the polyimide liquid crystal alignment film of the film thickness of 100 nm which performed the alignment process. In addition, as a counter substrate, a glass substrate with a columnar spacer having a height of 4 μm on which an ITO electrode was formed on the back surface was also obtained in the same manner as above to obtain a substrate with an alignment-treated polyimide liquid crystal alignment film. The two substrates with the liquid crystal alignment film were set as one group, the sealant was printed on one substrate with the liquid crystal injection port, the other substrate was facing the liquid crystal alignment film, and the polarized ultraviolet light was polarized. The surface projected on the line segment direction of the substrate is attached and pressed in such a way that it becomes parallel. Then, the sealant was hardened to produce ghosts with a cell gap of 4 μm. Liquid crystal MLC-7026-100 (negative type liquid crystal manufactured by MERCK) was injected into the empty cells by a reduced pressure injection method, and the injection port was sealed to obtain a liquid crystal cell of the FFS method. Subsequently, the obtained liquid crystal cells were heated at 120° C. for 30 minutes, and then left at 23° C. overnight, and then used for evaluation of liquid crystal alignment properties and accumulated charge relaxation properties.

<Evaluation of Liquid Crystal Alignment> Using the above-mentioned liquid crystal cell, under a constant temperature environment of 70°C, an AC voltage of 16VPP was applied at a frequency of 30Hz for 96 hours. Then, it was set as the state which short-circuited between the pixel electrode of a liquid crystal cell and a counter electrode, and was left to stand overnight at 23 degreeC as it is.

After placing, the liquid crystal cell was placed between two polarizers arranged with the polarization axes perpendicular to each other, and the backlight was turned on without applying voltage, and the arrangement angle of the liquid crystal cell was adjusted to minimize the brightness of the transmitted light. Next, the rotation angle when the liquid crystal cell is rotated from the angle at which the second region of the first pixel becomes the darkest to the angle at which the first region becomes the darkest is calculated as the angle Δ. Similarly, for the second pixel, the second area and the first area are compared, and the same angle Δ is calculated. Next, the average value of the angle Δ values between the first pixel and the second pixel is calculated as the angle Δ of the liquid crystal cell. When the value of the angle Δ of the liquid crystal cell was less than 1.0°, it was defined as "good", and when the value of the angle Δ was 1.0° or more, it was defined as "poor" and evaluated.

<Evaluation of the relaxation characteristics of accumulated charge> The above-mentioned liquid crystal cell was placed between two polarizers arranged so that the polarization axes were perpendicular to each other, and the pixel electrode and the counter electrode were short-circuited and set to the same potential. The LED backlight is irradiated under the two polarizers, and the angle of the liquid crystal cell is adjusted to minimize the brightness of the transmitted light from the LED backlight measured on the two polarizers.

Next, while applying a rectangular wave with a frequency of 30 Hz to the liquid crystal cell, the V-T characteristic (voltage-transmittance characteristic) at a temperature of 23° C. was measured, and an AC voltage with a relative transmittance of 23% was calculated. Since the AC voltage corresponds to a region with a large change in brightness relative to the voltage, it is suitable for evaluating the accumulated charge by brightness.

Next, an AC voltage with a relative transmittance of 23% was applied at a temperature of 23°C, and a rectangular wave with a frequency of 30Hz was applied for 5 minutes, and then driven with a DC voltage of +1.0V for 30 minutes. After that, the DC voltage was cut off, and only the AC voltage with a relative transmittance of 23% and a rectangular wave with a frequency of 30 Hz was applied again for 30 minutes.

The faster the accumulated charge relaxes, the faster the charge accumulation on the liquid crystal cell when the DC voltage is superimposed. Therefore, the relaxation characteristic of the accumulated charge is from the state where the relative transmittance is above 30% immediately after the DC voltage is superimposed, and 30 minutes The degree to which the relative transmittance is reduced is then evaluated. That is, when the relative transmittance decreased to less than 28% after the DC voltage was superimposed for 30 minutes, it was defined as "good", and when the relative transmittance was 28% or more, it was defined as "poor" and evaluated.

<Preparation of liquid crystal cells for voltage holding ratio evaluation> Except for using a glass substrate with ITO electrodes, before the sealant printing, 4 μm bead spacers were scattered on the surface of the liquid crystal alignment film on the single substrate to be consistent with the above-mentioned liquid crystal. The liquid crystal cell for measuring the voltage holding ratio was produced in the same procedure as the production of the liquid crystal cell for the evaluation of the relaxation properties of the alignment and the accumulated charge.

<Evaluation of voltage holding ratio> The voltage holding ratio was evaluated using the above-mentioned liquid crystal cell. Specifically, an AC voltage of 2 VPP was applied to the liquid crystal cell obtained by the above method at a temperature of 70° C. for 60 microseconds, and the voltage after 167 milliseconds was measured to calculate how much voltage could be maintained as the voltage holding ratio (also called VHR). In addition, the measurement was performed using a voltage holding ratio measuring device (VHR-1, manufactured by Toyo Technology Co., Ltd.), and performed with the settings of voltage: ±1 V, pulse width: 60 μs, and frame period: 167 ms. When the value of the voltage holding ratio of the liquid crystal cell was 95% or more, it was defined as "good", and when the value of the voltage holding ratio was less than 95%, it was defined as "defective" and evaluated.

<Example 5> Using the liquid crystal aligning agent (A-1) obtained in Example 1, two types of liquid crystal cells were produced as described above. The irradiation of polarized ultraviolet rays is carried out using a high-pressure mercury lamp, with a wavelength selective filter: 240LCF and a 254nm type polarizer. The irradiation dose of polarized ultraviolet rays is measured by using an illuminometer UVD-S254SB manufactured by USHIO Electric Co., Ltd., and the wavelength is 254nm in the range of 600~1800mJ/cm ² . Liquid crystal cells.

As a result of evaluating the liquid crystal alignment properties of these liquid crystal cells, the polarized ultraviolet irradiation amount with the best angle Δ was 1500 mJ/cm ² , and the angle Δ was 0.56°, which was favorable. In addition, the accumulated charge relaxation properties of the same polarized ultraviolet irradiation amount previously evaluated before the evaluation of the liquid crystal alignment were good relative transmittance of 26.0% after the DC voltage was superimposed for 30 minutes. In addition, as a result of evaluating the voltage retention rate of the liquid crystal cells produced with the same amount of ultraviolet irradiation, the voltage retention rate was 96.8%, which was favorable.

<Examples 6 to 8> Except for using the liquid crystal aligning agents obtained in Examples 2 to 4, the same methods as in Example 5 were used to evaluate the liquid crystal alignment, the relaxation characteristics of accumulated charges, and the voltage retention.

<Comparative Examples 4 to 6> Except for using the liquid crystal aligning agents obtained in Comparative Examples 1 to 3, in the same manner as in Example 5, the liquid crystal alignment properties, the relaxation properties of accumulated charges, and the voltage retention were evaluated.

Table 1 shows the amount of polarized ultraviolet irradiation with the best angle Δ when using the liquid crystal alignment agents obtained in Examples 1 to 4 and Comparative Examples 1 to 3, the evaluation results of liquid crystal alignment, the evaluation results of the relaxation characteristics of accumulated charges, and the voltage retention ratio the evaluation results.

As shown in Table 1, in Examples 5 to 8, the angle Δ of the difference between the alignment azimuth angles before and after the AC drive was less than 1.0° and was good, and at the same time, the relative transmittance after the DC voltage superimposing the accumulated charge relaxation characteristic for 30 minutes was It is good if it is less than 28.0%, and the voltage holding ratio is also 95% or more, showing good characteristics, all of which are good afterimage characteristics, so the display quality of the liquid crystal display element is improved and excellent. on the other hand. In Comparative Examples 4 to 6, the relative transmittance and the voltage retention rate after the angle Δ and the DC voltage were superimposed for 30 minutes were not all good results. It was confirmed that the liquid crystal display element manufactured by the method of the present invention showed very excellent afterimage characteristics. [Industrial Availability]

The substrate for a lateral electric field driven liquid crystal display element manufactured using the composition of the present invention or a lateral electric field driven liquid crystal display element having the substrate is excellent in reliability, and can be preferably used in large-screen and high-definition liquid crystal televisions, etc. . Moreover, since the liquid crystal alignment film produced by the method of the present invention has excellent liquid crystal alignment stability and reliability, it can also be used in a variable phase device using liquid crystal, and the variable phase device can be preferably used in, for example, resonance. Antennas with variable frequency, etc.

Claims (6)

A liquid crystal aligning agent comprising: a polymer (A) obtained from a polyamide acid obtained by using a tetracarboxylic dianhydride component and a diamine component containing a diamine represented by the following formula (1), and the polyamide At least one selected from the imidized polymers of amine acids; and a polymer (B) obtained by using a tetracarboxylic dianhydride component and a diamine component containing a diamine represented by the following formula (2) At least one selected from the group consisting of polyamides and imidized polymers of the polyamides,

In formula (1), X represents -(CH ₂ ) _n -, n represents the number of -(CH ₂ )- and is a natural number of 8 or 9, any -(CH ₂ )- can be independently processed from The groups selected from -O-, -S-, -COO-, -OCO-, -CONH- and -NHCO- are substituted on the condition that these groups are not adjacent, and R ₁ and R ₂ are independently monovalent organic groups, p1 and p2 are each independently an integer of 0 to 4. In formula (2), Y ₁ is at least one selected from the structures of the following formulae (YD-1) to (YD-5), and B ₁ and B ₂ are respectively independently a hydrogen atom, or an alkyl, alkenyl or alkynyl group with 1 to 10 carbon atoms that may have a substituent;

In formula (YD-1), A ₁ is a nitrogen atom-containing heterocycle with 3 to 15 carbon atoms, Z ₁ is a hydrogen atom or a hydrocarbon group with 1 to 20 carbon atoms that may have a substituent, in formula (YD-2) , W ₁ is a hydrocarbon group with a carbon number of 1 to 10, A ₂ is a monovalent organic group with a nitrogen atom-containing heterocyclic ring with a carbon number of 3 to 15, or a disubstituted amine substituted by an aliphatic group with a carbon number of 1 to 6 base, in formula (YD-3), W ₂ is a divalent organic group with 6 to 15 carbon atoms and 1 to 2 benzene rings, W ₃ is an alkylidene or biphenylene group with a carbon number of 2 to 5 or A divalent organic group with a carbon number of 12 to 18 containing a heterocyclic ring containing a nitrogen atom, Z ₂ is a hydrogen atom, an alkyl group with a carbon number of 1 to 5 or a benzene ring, a is an integer of 0 to 1, the formula (YD-4 ) in, A ₃ is the heterocyclic ring containing nitrogen atom of carbon number 3～15, in formula (YD-5), A ₄ is the heterocyclic ring containing nitrogen atom of carbon number 3～15, W ₅ is carbon number 2～ 5 of the alkyl group. The liquid crystal aligning agent according to claim 1, wherein A ₁ , A ₂ , A ₃ and A ₄ described in formulas (YD-1), (YD-2), (YD-4) and (YD-5) are derived from At least one selected from the group consisting of pyrrolidine, pyrrole, imidazole, pyrazole, oxazole, thiazole, piperidine, piperazine, pyridine, pyrazine, indole, benzimidazole, quinoline, isoquinoline and carbazole 1 type. The liquid crystal aligning agent according to claim 1, wherein Y ₁ in formula (2) is at least 1 selected from the group consisting of divalent organic groups having structures of the following formulas (YD-6) to (YD-22). kind,

In formula (YD-17), h is an integer of 1 to 3, and in formula (YD-14), (YD-21) and (YD-22), j is an integer of 0 to 3. The liquid crystal aligning agent of claim 3, wherein Y ₁ in the formula (2) is derived from 2 having the structures of the above formulae (YD-14), (YD-18), (YD-21) and (YD-22) At least one selected from the group consisting of valent organic groups. A liquid crystal alignment film, which is obtained by using the liquid crystal alignment agent according to any one of claims 1 to 4. A liquid crystal display element comprising the liquid crystal alignment film of claim 5.