TWI850341B - Liquid crystal alignment treating agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Abstract

Provided is a reverse-type liquid crystal display element having high vertical alignment of liquid crystal and good optical properties (i.e., good transparency when no external voltage is applied and good scattering properties when an external voltage is applied), furthermore, high adhesion between the liquid crystal layer and the liquid crystal alignment film, and the ability to maintain such properties even in an environment of high temperature and high humidity or exposure to light for a long time. A liquid crystal display element having a liquid crystal layer and a liquid crystal alignment film on at least one of the substrates, and a transmissive scattering type reverse liquid crystal display element which is transparent when no external voltage is applied and scattering when an external voltage is applied, wherein the liquid crystal layer is formed by curing a liquid crystal composition comprising liquid crystal and a polymerizable compound disposed between a pair of substrates having electrodes by applying at least one of active energy rays and heat, wherein the liquid crystal alignment film is obtained by a liquid crystal alignment treatment agent comprising the following components (A) and (B), wherein: (A) component: a compound having a group of the following formula [1], (B) component: a polymer having a structure selected from at least one of the following formulas [2-1] and [2-2], ＊Indicates the bonding part with other structures. The symbols are defined as in the manual.

Description

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

The present invention relates to a transmissive scattering type reverse mode liquid crystal display element which is in a transparent state when no external voltage is applied and in a scattering state when an external voltage is applied.

As a liquid crystal display element, the TN (Twisted Nematic) mode has been put into practical use. In this mode, a polarizing plate must be used to switch light using the optical rotation characteristics of liquid crystal. If a polarizing plate is used, the efficiency of light utilization will be reduced.

As a liquid crystal display element that does not use a polarizing plate, there are elements that switch between the transmission state (also called transparent state) and the scattering state of the liquid crystal. Generally speaking, it is known to use polymer dispersed liquid crystal (also called PDLC (Polymer Dispersed Liquid Crystal)) or polymer network liquid crystal (also called PNLC (Polymer Network Liquid Crystal)). In such liquid crystal display elements, a liquid crystal composition is arranged between a pair of substrates having electrodes, and the liquid crystal composition includes a polymerizable compound that can be polymerized by ultraviolet rays. The liquid crystal composition is cured by irradiation with ultraviolet rays to form a composite of liquid crystal and a cured product of the polymerizable compound (such as a polymer network). In addition, in the liquid crystal display element, the transmission state and scattering state of the liquid crystal can be controlled by applying a voltage. In the past, most of the liquid crystal display elements using PDLC or PNLC were normal mode liquid crystal display elements (also called normal mode elements). When there is no external voltage, the liquid crystal molecules present irregular directions, so they become cloudy (scattering) state. When an external voltage is applied, the liquid crystal is arranged in the direction of the electric field, and becomes a penetrating state that allows light to pass through. However, in the case of normal mode elements, in order to obtain the penetrating state, it is necessary to apply voltage frequently, so the situation of using in a transparent state is more common. For example, when used on window glass, the power consumption will increase. On the other hand, a reverse mode liquid crystal display element (also called reverse mode element) using PDLC has been proposed, which becomes a penetrating state when there is no external voltage and a scattering state when an external voltage is applied (refer to patent documents 1, 2). [Prior art literature] [Patent literature]

[Patent document 1] Japanese Patent No. 2885116 [Patent document 2] Japanese Patent No. 4132424

[The problem that the invention wants to solve]

Since the reverse type element must make the liquid crystal align vertically, a liquid crystal alignment film that makes the liquid crystal align vertically is used. However, because the liquid crystal alignment film is a highly hydrophobic film, there is a problem of reduced adhesion between the liquid crystal layer and the liquid crystal alignment film. Therefore, a large amount of polymerizable compounds used to improve the adhesion between the liquid crystal layer and the liquid crystal alignment film must be introduced into the liquid crystal composition used for the reverse type element. However, if a large amount of polymerizable compounds are introduced, the vertical alignment of the liquid crystal will be hindered, and there will be a problem that the transparency when there is no external voltage and the scattering characteristics when the external voltage is applied will be greatly reduced. Therefore, the liquid crystal alignment film used in the reverse type element must be a liquid crystal alignment film with high vertical alignment of the liquid crystal. Furthermore, since the inverted type device is often attached to the window glass of a car or a building, it must have the following characteristics: "Even in a harsh environment of high temperature and high humidity or exposure to light for a long time, the vertical alignment of the liquid crystal will not decrease, and the adhesion between the liquid crystal layer and the liquid crystal alignment film is high."

Therefore, the purpose of the present invention is to provide a liquid crystal with high vertical orientation and good optical properties (i.e., good transparency when no external voltage is applied and good scattering properties when an external voltage is applied), and further, the liquid crystal layer and the liquid crystal alignment film have high adhesion, and even in a long-term, high temperature and high humidity environment or in an environment exposed to light, the reverse type liquid crystal display element can still maintain these properties. [Means for solving the problem]

The inventors of the present invention have completed the present invention having the following gist as a result of in-depth research in order to achieve the above-mentioned purpose. That is, a liquid crystal display element having a liquid crystal layer and a liquid crystal alignment film on at least one side of the substrate, and a transmissive scattering type reverse liquid crystal display element which becomes transparent when no external voltage is applied and becomes a scattering state when an external voltage is applied, wherein the liquid crystal layer is formed by applying at least one of active energy rays and heat to a liquid crystal composition including liquid crystal and a polymerizable compound disposed between a pair of substrates having electrodes to harden it, and wherein the liquid crystal alignment film is obtained by a liquid crystal alignment treatment agent comprising the following components (A) and (B). Component (A): a compound having a group of the following formula [1] (also referred to as a specific compound). Component (B): A polymer having at least one structure selected from the following formula [2-1] and formula [2-2] (also referred to as specific structure (1)).

＊Indicates the bonding site with other structures.

^X1 represents at least one selected from a single bond, -( _CH2 ) _a- (a is an integer of 1 to 15), -O-, _-CH2O- , -CONH-, -NHCO-, -CON( _CH3 )-, -N( _CH3 )CO-, -COO- and -OCO-. ^X2 represents a single bond or -( _CH2 ) _b- (b is an integer of 1 to 15). ^X3 represents at least one selected from a single bond, -( _CH2 ) _c- (c is an integer of 1 to 15), -O-, _-CH2O- , -COO- and -OCO-. ^X4 represents at least one divalent cyclic group selected from a benzene ring, a cyclohexane ring and a heterocyclic ring, or a divalent organic group having 17 to 51 carbon atoms and having a steroid skeleton, and any hydrogen atom on the aforementioned cyclic group may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorinated alkyl group having 1 to 3 carbon atoms, a fluorinated alkoxy group having 1 to 3 carbon atoms, or a fluorine atom. ^X5 represents at least one cyclic group selected from a benzene ring, a cyclohexane ring and a heterocyclic ring, and any hydrogen atom on the aforementioned cyclic group may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorinated alkyl group having 1 to 3 carbon atoms, a fluorinated alkoxy group having 1 to 3 carbon atoms, or a fluorine atom. Xn represents an integer of 0 to 4. ^X6 represents at least one selected from an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, a fluorinated alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, and a fluorinated alkoxy group having 1 to 18 carbon atoms.

^X7 represents at least one selected from a single bond, -O-, _-CH2O- , -CONH-, -NHCO-, -CON( _CH3 )-, -N( _CH3 )CO-, -COO-, and -OCO-. ^X8 represents an alkyl group having 8 to 22 carbon atoms or a fluorinated alkyl group having 6 to 18 carbon atoms. [Effects of the Invention]

According to the present invention, a liquid crystal display device having high vertical orientation and good optical properties (i.e., good transparency when no external voltage is applied and good scattering properties when an external voltage is applied) can be obtained. Furthermore, the liquid crystal layer and the liquid crystal alignment film have high adhesion, and these properties can be maintained even in an environment of high temperature and high humidity or exposure to light for a long time. The mechanism of why the liquid crystal display device having the above-mentioned excellent properties can be obtained by the present invention is not clear, but it can be roughly inferred as follows.

The specific compound contained in the liquid crystal alignment treatment agent used to make the liquid crystal alignment film of the liquid crystal display element has a disulfide bond (S-S) and a thioketone (C=S) group, so that the adhesion between the liquid crystal alignment film and the metal electrode becomes higher. In addition, the amine group (N) in the characteristic compound exhibits weak alkalinity, so it is believed that it can promote the reaction of the polymerizable compound in the liquid crystal composition to form a stronger polymer network. In addition, the liquid crystal alignment film of the present invention is obtained by a liquid crystal alignment treatment agent containing a polymer having a specific structure (1) of the above-mentioned formula [2-1] or formula [2-2]. Since the specific structure (1) of formula [2-1] exhibits a rigid structure, a liquid crystal display element using a liquid crystal alignment film having this structure can obtain a highly stable vertical alignment of the liquid crystal. Therefore, in particular, when the specific structure (1) of formula [2-1] is used, it is believed that a reverse type element exhibiting good optical properties can be obtained. The liquid crystal display element obtained by using a liquid crystal alignment treatment agent containing a polymer having a specific compound and a specific structure (1) in this way becomes a liquid crystal display element having the aforementioned properties. Therefore, the liquid crystal display element of the present invention can be used in a liquid crystal display for display purposes, or a dimming window or light shutter element for controlling the blocking and penetration of light.

[Best form for implementing the invention] <Specific compound>

The specific compound is a compound of the above formula [1]. As a specific example of the specific compound, the following formula [1a] can be cited.

^T1 represents at least one structure selected from the following formula [1-a] to formula [1-h].

T ^A represents an alkyl group having 1 to 3 carbon atoms.

Among them, formula [1-b], formula [1-c] or formula [1-d] is preferred. ^T2 represents a single bond or an organic group having 1 to 18 carbon atoms. Among them, a single bond or an organic group having 1 to 6 carbon atoms is preferred. ^T3 represents the structure of the above formula [1].

As a more specific example of the specific compound, the following formula [1-1a] can be cited, and it is preferably used.

The usage ratio of the specific compound is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the total polymer from the viewpoint of the adhesion between the liquid crystal alignment film and the metal electrode. It is more preferably 0.5 to 20 parts by mass. The most preferred ratio is 1 to 15 parts by mass. In addition, the specific compound can be used in one type according to various characteristics, or two or more types can be mixed and used. <Specific structure (1)> Specific structure (1) is the structure of the above-mentioned formula [2-1] or formula [2-2]. In formula [2-1], ^X1 to ^X6 and Xn are as defined above, among which the following are preferably used. From the viewpoint of availability of raw materials or ease of synthesis, ^X1 is preferably a single bond, -( _CH2 ) _a- (a is an integer of 1 to 15), -O-, _-CH2O- or -COO-. More preferably, it is a single bond, -( _CH2 ) _a- (a is an integer of 1 to 10), -O-, _-CH2O- or -COO-. ^X2 is preferably a single bond or -( _CH2 ) _b- (b is an integer of 1 to 10). From the viewpoint of ease of synthesis, ^X3 is preferably a single bond, -( _CH2 ) _a- (a is an integer of 1 to 15), -O-, _-CH2O- or -COO-. More preferably, it is a single bond, -(CH ₂ ) _a - (a is an integer of 1 to 10), -O-, -CH ₂ O- or -COO-. From the viewpoint of ease of synthesis, X ⁴ is preferably a benzene ring, a cyclohexane ring or an organic group having 17 to 51 carbon atoms and a steroid skeleton. X ⁵ is preferably a benzene ring or a cyclohexane ring. X ⁶ is preferably an alkyl group having 1 to 18 carbon atoms, a fluorinated alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 18 carbon atoms or a fluorinated alkoxy group having 1 to 10 carbon atoms. More preferably, it is an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms. Particularly preferably, it is an alkyl group having 1 to 9 carbon atoms or an alkoxy group having 1 to 9 carbon atoms. From the viewpoint of the availability of raw materials or the ease of synthesis, Xn is preferably 0 to 3, and more preferably 0 to 2.

Preferred combinations of ^X1 to ^X6 and Xn include the same combinations as those disclosed in Tables 6 to 47 on pages 13 to 34 of International Publication WO2011/132751 (published on October 27, 2011), (2-1) to (2-629). In addition, in the tables of the International Publication, ^X1 to ^X6 in the present invention are represented by Y1 to Y6, and Xn is represented by n, but Y1 to Y6 can be interpreted as ^X1 to ^X6 , and n can be interpreted as Xn. In addition, in (2-605) to (2-629) disclosed in the tables of the international publications, the organic group having 17 to 51 carbon atoms and having a steroid skeleton in the present invention is represented by an organic group having 12 to 25 carbon atoms and having a steroid skeleton, but the organic group having 12 to 25 carbon atoms and having a steroid skeleton can be interpreted as an organic group having 17 to 51 carbon atoms and having a steroid skeleton.

Among them, the combination of (2-25) to (2-96), (2-145) to (2-168), (2-217) to (2-240), (2-268) to (2-315), (2-364) to (2-387), (2-436) to (2-483) or (2-603) to (2-615) is preferred. Particularly preferred are (2-49) to (2-96), (2-145) to (2-168), (2-217) to (2-240), (2-603) to (2-606), (2-607) to (2-609), (2-611), (2-612) or (2-624).

In formula [2-2], ^X7 and ^X8 are as defined above, and the following are preferred.

^X7 is preferably a single bond, -O-, _-CH2O- , -CONH-, -CON( _CH3 )- or -COO-. More preferably, it is a single bond, -O-, -CONH- or -COO-. ^X8 is preferably an alkyl group having 8 to 18 carbon atoms.

As described above, the specific structure (1) in the present invention is preferably a structure of formula [2-1] from the viewpoint of obtaining a highly stable vertical alignment of liquid crystal. The specific structure (1) is preferably a form included in the repeating units constituting the polymer. Relative to the entire repeating units constituting the polymer, the repeating units containing the specific structure (1) are preferably included in an amount of 10 to 80 mol%, and more preferably 20 to 70 mol%. In addition, the polymer having the specific structure (1) can be used in one type or in a mixture of two or more types according to various characteristics. <Specific structure (2)> The polymer in the present invention is preferably further provided with at least one structure selected from the following formulas [3-a] to [3-i] (also referred to as specific structure (2)).

Y ^A represents a hydrogen atom or a benzene ring. Among them, formula [3-a] to formula [3-f] are preferred. Formula [3-a] to formula [3-e] are more preferred. From the perspective of the adhesion between the liquid crystal layer and the liquid crystal alignment film, formula [3-a], formula [3-b], formula [3-d] or formula [3-e] are particularly preferred. The liquid crystal alignment treatment agent in the present invention is preferably further comprised of a polymer having a specific structure (2). The specific structure (2) is preferably a form contained in the repeating units constituting the polymer. Relative to the total repeating units constituting the polymer, it is preferably comprised of 10 to 70 mol% of repeating units containing the specific structure (2), and it is more preferably comprised of 20 to 60 mol%. It is believed that by using the specific structure (2), during the ultraviolet irradiation or heating step when manufacturing the liquid crystal display element, a photoreaction occurs with the reactive group of the polymerizable compound in the liquid crystal composition, thereby strengthening the adhesion between the liquid crystal layer and the liquid crystal alignment film. <Polymer> The polymer is not particularly limited, and preferably at least one polymer selected from acrylic polymers, methacrylic polymers, novolac resins, polyhydroxystyrene, polyimide precursors, polyimide, polyamide, polyester, cellulose, and polysiloxane. More preferably, it is a polyimide precursor or a polyimide. When a polyimide precursor or polyimide (collectively referred to as a polyimide-based polymer) is used as the polymer, a polyimide precursor or polyimide obtained by reacting a diamine component with a tetracarboxylic acid component is preferred.

The polyimide precursor has a structure of the following formula [A].

^R1 represents a tetravalent organic group. ^R2 represents a divalent organic group. ^A1 and ^A2 represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. ^A3 and ^A4 represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or an acetyl group. n represents a positive integer.

The diamine component is a diamine having two primary or secondary amino groups in the molecule, and the tetracarboxylic acid component includes a tetracarboxylic acid compound, a tetracarboxylic dianhydride, a tetracarboxylic acid dihalide compound, a tetracarboxylic acid dialkyl ester compound, or a tetracarboxylic acid dialkyl ester dihalide compound.

A polyimide polymer can be obtained relatively easily by using a tetracarboxylic dianhydride of the following formula [B] and a diamine of the following formula [C] as raw materials. For such reasons, a polyimide formed by a structure of repeating units of the following formula [D] or a polyimide obtained by imidizing the polyimide is preferred.

^R1 and ^R2 are the same as defined in formula [A].

^R1 and ^R2 are the same as defined in formula [A].

Furthermore, according to a conventional synthesis method, an alkyl group having 1 to 8 carbon atoms in ^A1 and ^A2 in formula [A], and an alkyl group having 1 to 5 carbon atoms or an acetyl group in ^A3 and ^A4 in formula [A] may be introduced into the polymer of formula [D] obtained above. As a method for introducing the specific structure (1) into the polyimide polymer, it is preferred to use a diamine having the specific structure (1) as part of the raw materials. Among them, it is preferred to use a diamine having a structure selected from at least one of the above formulas [2-1] and [2-2] (also referred to as specific diamine (1)).

In particular, it is preferred to use a diamine of the following formula [2a].

X represents at least one structure selected from the above formula [2-1] and formula [2-2]. In formula [2-1], the details of X ¹ to X ⁶ and Xn, and the preferred combination thereof are the same as those of formula [2-1], and the details of X ⁷ and X ⁸ in formula [2-2] and the preferred combination thereof are the same as those of formula [2-2]. Xm represents an integer of 1 to 4. Among them, 1 or 2 is preferred. Specific examples of the specific diamine (1) of formula [2-1] include diamine compounds of formula [2-1] to formula [2-6] and formula [2-9] to formula [2-36] described on pages 15 to 19 of International Publication No. WO2013/125595 (published on August 29, 2013). In the description of International Publication WO2013/125595, _R2 in Formula [2-1] to Formula [2-3] and _R4 in Formula [2-4] to Formula [2-6] represent at least one selected from the group consisting of an alkyl group having 1 to 18 carbon atoms, a fluorinated alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, and a fluorinated alkoxy group having 1 to 18 carbon atoms. In addition, _A4 in Formula [2-13] represents a linear or branched alkyl group having 3 to 18 carbon atoms. In addition, _R3 in Formula [2-4] to Formula [2-6] represents at least one selected from the group consisting of -O-, _-CH2O- , -COO-, and -OCO-.

Among them, the preferred diamine is a diamine compound of formula [2-1] to formula [2-6], formula [2-9] to formula [2-13] or formula [2-22] to formula [2-31] described in International Publication WO2013/125595. From the viewpoint of the optical properties of the liquid crystal display element, the diamine of the following formula [2a-32] to formula [2a-41] is more preferred.

^R1 and ^R2 each represent an alkyl group having 3 to 12 carbon atoms.

^R3 and ^R4 each represent an alkyl group having 3 to 12 carbon atoms, and the cis-trans isomerism of the 1,4-cyclohexylene group is a trans isomer. From the viewpoint of the optical properties of the liquid crystal display element, the best is the diamine of the above formula [2a-35] to [2a-37], [2a-40] or [2a-41]. Specific examples of the specific diamine (1) of the formula [2-2] include diamine compounds of the formula [DA1] to [DA11] described on page 23 of International Publication WO2013/125595 (published on August 29, 2013). In the description of International Publication WO2013/125595, _A1 in Formula [DA1] to Formula [DA5] represents an alkyl group having 8 to 22 carbon atoms or a fluorinated alkyl group having 6 to 18 carbon atoms. The proportion of the specific diamine (1) used is preferably 10 to 80 mol% relative to the total diamine component from the viewpoint of the optical properties of the liquid crystal display element and the adhesion between the liquid crystal layer and the liquid crystal alignment film. More preferably, it is 20 to 70 mol%. In addition, the specific diamine (1) can be used in one type according to the respective properties, or two or more types can be mixed and used. As a method for introducing the specific structure (2) into the polyimide-based polymer, it is preferred to use a diamine having the specific structure (2) as part of the raw materials. In particular, it is preferred to use a diamine having a structure of the following formula [3] (also referred to as specific diamine (2)).

^Y1 represents at least one selected from a single bond, -O-, -NH-, -N(CH ₃ )-, -CH ₂ O-, -CONH-, -NHCO-, -CON(CH ₃ )-, -N(CH ₃ )CO-, -COO-, and -OCO-. Among them, a single bond, -O-, -CH ₂ O-, -CONH-, -COO-, or -OCO- is preferred. In terms of availability of raw materials or ease of synthesis, a single bond, -O-, -CH ₂ O-, or -COO- is more preferred. ^Y2 represents a single bond, an alkylene group having 1 to 18 carbon atoms, or an organic group having 6 to 24 carbon atoms having a cyclic group selected from a benzene ring, a cyclohexane ring, and a heterocyclic ring, and any hydrogen atom on the cyclic group may be substituted with an alkylene group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorinated alkyl group having 1 to 3 carbon atoms, a fluorinated alkoxy group having 1 to 3 carbon atoms, or a fluorine atom. Among them, a single bond, an alkylene group having 1 to 12 carbon atoms, a benzene ring, or a cyclohexane ring is preferred. From the viewpoint of the adhesion between the liquid crystal layer and the liquid crystal alignment film, a single bond or an alkylene group having 1 to 12 carbon atoms is more preferred. ^Y3 represents at least one selected from a single bond, -O-, -NH-, -N( _CH3 )-, -CH2O-, _-CONH- , -NHCO-, -CON( _CH3 )-, -N( _CH3 )CO-, -COO- and -OCO-. Among them, a single bond, -O-, -COO- or -OCO- is preferred. A single bond or -OCO- is more preferred. ^Y4 represents at least one structure selected from the aforementioned formulas [3-a] to [3-i]. Among them, formulas [3-a] to [3-f] are preferred. Formulas [3-a] to [3-e] are more preferred. From the viewpoint of adhesion between the liquid crystal layer and the liquid crystal alignment film, formula [3-a], formula [3-b], formula [3-d] or formula [3-e] is particularly preferred. Yn represents an integer from 1 to 4, wherein 1 or 2 is preferred.

Among the specific diamines (2), the diamine of the following formula [3a] is preferably used.

Y represents the structure of the above formula [3]. In addition, the details and preferred combinations of Y ¹ to X ⁴ and Xn in formula [3] are the same as those of the above formula [3]. Ym represents an integer of 1 to 4, wherein 1 is preferred.

More specific specific diamines (2) include the following formulas [3a-1] to [3a-12], and these are preferably used.

n1 represents an integer from 2 to 12.

n2 represents an integer from 0 to 12. n3 represents an integer from 2 to 12.

Among them, formula [3a-1], formula [3a-2], formula [3a-5] to formula [3a-7], formula [3a-11] or formula [3a-12] are preferred. Formula [3a-5] to formula [3a-7], formula [3a-11] or formula [3a-12] are more preferred. The proportion of specific diamine (2) used is preferably 10 to 70 mol% relative to the total diamine component from the viewpoint of the optical properties of the liquid crystal display element and the adhesion between the liquid crystal layer and the liquid crystal alignment film. More preferably, it is 20 to 60 mol%. In addition, the specific diamine (2) can be used in one type according to the respective properties, or two or more types can be mixed and used. As the diamine component for producing the polyimide-based polymer, diamines other than the specific diamine (1) and the specific diamine (2) (also referred to as other diamines) may be used.

Specifically, other diamine compounds described on pages 27 to 30 of International Publication WO2015/012368 (published on January 29, 2015) and diamine compounds of formula [DA1] to [DA14] described on pages 30 to 32 of the same publication can be cited. In addition, other diamines can be used alone or in combination of two or more depending on the properties.

In the present invention, from the viewpoint of the optical properties of the liquid crystal display element and the adhesion between the liquid crystal layer and the liquid crystal alignment film, it is preferred to use both the specific diamine (1) and the specific diamine (2). As the tetracarboxylic acid component for preparing the polyimide polymer, it is preferred to use the tetracarboxylic dianhydride of the following formula [4], or a tetracarboxylic acid, a tetracarboxylic acid dihalide, a tetracarboxylic acid dialkyl ester or a tetracarboxylic acid dialkyl ester dihalide (all of which are collectively referred to as specific tetracarboxylic acid components) as a derivative of the tetracarboxylic acid.

Z represents at least one structure selected from the following formula [4a] to formula [41].

^ZA to ^ZD represent a hydrogen atom, a methyl group, a chlorine atom or a benzene ring, respectively. ^ZE and ^ZF represent a hydrogen atom or a methyl group, respectively.

Among them, Z in formula [4] is preferably formula [4a], formula [4c], formula [4d], formula [4e], formula [4f], formula [4g], formula [4k] or formula [4l] from the viewpoint of ease of synthesis or ease of polymerization reactivity when producing a polymer. More preferably, it is formula [4a], formula [4e], formula [4f], formula [4g], formula [4k] or formula [4l]. From the viewpoint of optical properties of a liquid crystal display element, formula [4a], formula [4e], formula [4f], formula [4g] or formula [4l] is particularly preferred. The proportion of the specific tetracarboxylic acid component used is preferably 1 mol% or more relative to the total tetracarboxylic acid component. More preferably, it is 5 mol% or more, and particularly preferably, it is 10 mol% or more. From the perspective of the optical properties of liquid crystal display elements, the optimum range is 10 to 90 mol %.

Other tetracarboxylic acid components other than the specific tetracarboxylic acid component can be used in the polyimide polymer. As other tetracarboxylic acid components, tetracarboxylic acid compounds, tetracarboxylic acid dianhydrides, dicarboxylic acid dihalogen compounds, dicarboxylic acid dialkyl ester compounds or dialkyl ester dihalogen compounds shown below can be cited. Specifically, other tetracarboxylic acid components described on pages 34 to 35 of International Publication WO2015/012368 (published on January 29, 2015) can be cited. The specific tetracarboxylic acid component and other tetracarboxylic acid components can be used alone or in combination of two or more depending on the characteristics. The method for synthesizing the polyimide polymer is not particularly limited. It is usually obtained by reacting a diamine component with a tetracarboxylic acid component. Specifically, the method described on pages 35 to 36 of International Publication WO2015/012368 (published on January 29, 2015) can be cited.

The reaction of the diamine component and the tetracarboxylic acid component is usually carried out in a solvent containing the diamine component and the tetracarboxylic acid component. The solvent used in this case is not particularly limited as long as it can dissolve the generated polyimide precursor.

Specifically, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, or 1,3-dimethyl-imidazolidinone can be mentioned. In addition, when the solvent solubility of the polyimide precursor is high, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or a solvent of the following formula [D1] to [D3] can be used.

^D1 and ^D2 represent an alkyl group having 1 to 3 carbon atoms. ^D3 represents an alkyl group having 1 to 4 carbon atoms. Moreover, these groups can be used alone or in combination. Furthermore, even a solvent that cannot dissolve the polyimide precursor can be mixed with the aforementioned solvent for use as long as the generated polyimide precursor is within a range where the generated polyimide precursor does not precipitate. Moreover, the moisture in the organic solvent will hinder the polymerization reaction and thus become the cause of the hydrolysis of the generated polyimide precursor, so it is preferred to use an organic solvent that has been dehydrated and dried. In the polymerization reaction of the polyimide precursor, when the total molar number of the diamine component is set to 1.0, the total molar number of the tetracarboxylic acid component is preferably 0.8 to 1.2. If the total molar number of the tetracarboxylic acid components is less than 1.0 (i.e., the total molar number of the tetracarboxylic acid components is less than the molar number of the diamine components), the terminal of the polymer will become an amine structure; if it is greater than 1.0 (i.e., the total molar number of the tetracarboxylic acid components is greater than the molar number of the diamine components), the terminal of the polymer will become a carboxylic anhydride or dicarboxylic acid structure. In the present invention, since the effect of the aforementioned specific compound will be further improved, it is preferred that the total molar number of the tetracarboxylic acid components is greater than 1.0, that is, the total molar number of the tetracarboxylic acid components is greater than the molar number of the diamine components. Specifically, when the total molar number of the diamine components is set to 1.0, the total molar number of the tetracarboxylic acid components is preferably 1.05~1.20.

Polyimide is obtained by ring-closing a polyimide precursor, and the ring-closing ratio of the amide group in the polyimide (also called the imidization ratio) does not necessarily need to be 100%, and can be arbitrarily adjusted according to the application or purpose. Among them, from the viewpoint of the solubility of the polyimide polymer in the solvent, 30-80% is preferred. More preferably, it is 40-70%.

The molecular weight of the polyimide polymer is preferably 5,000 to 1,000,000 Mw (weight average molecular weight) measured by GPC (Gel Permeation Chromatography) method in consideration of the strength of the resulting liquid crystal alignment film and the workability and coating properties of the liquid crystal alignment film during formation. More preferably, it is 10,000 to 150,000. <Liquid crystal alignment treatment agent> The liquid crystal alignment treatment agent comprises a specific compound and a polymer having a specific structure (1), and is preferably a solution for forming a liquid crystal alignment film, which is a solution containing a specific compound, a polymer having a specific structure (1) and a solvent.

The content of the polymer component in the liquid crystal alignment treatment agent of the present invention can be appropriately changed according to the thickness setting of the liquid crystal alignment film to be formed. From the perspective of forming a uniform and defect-free liquid crystal alignment film, it is preferably 1% by weight or more, and from the perspective of the storage stability of the solution, it is preferably 10% by weight or less. Among them, 2-8% by weight is preferred, and 3-7% by weight is particularly preferred. The polymer components contained in the liquid crystal alignment treatment agent can all be polymers having a specific structure (1), but as mentioned above, the present invention is preferably a polymer having both a characteristic structure (1) and a specific structure (2). At this time, even if a polymer having both a specific structure (1) and a specific structure (2) is used, a polymer having a specific structure (1) and a polymer having a specific structure (2) can also be used in combination. When used in combination, the ratio of the polymer having the specific structure (2) to 100 parts by weight of the polymer having the specific structure (1) is preferably 10 to 400 parts by weight, and more preferably 50 to 200 parts by weight. The polymer having the specific structure (2) may be used in one type or two or more types depending on the properties.

In addition, the polymer component may be mixed with a polymer other than the polymer having the specific structure (1) and the polymer having the specific structure (2). In this case, the usage ratio of the polymer not having the specific structure is preferably 10 to 200 parts by mass relative to 100 parts by mass of the polymer having the specific structure. More preferably, it is 10 to 100 parts by mass.

The content of the solvent in the liquid crystal alignment treatment agent can be appropriately selected from the perspective of the coating method of the liquid crystal alignment treatment agent or the viewpoint of obtaining the target film thickness. Among them, from the viewpoint of forming a more uniform liquid crystal alignment film by coating, the content of the solvent in the liquid crystal alignment treatment agent is preferably 50 to 99.9% by mass. More preferably, it is 60 to 99% by mass. Especially preferably, it is 65 to 99% by mass.

The solvent used in the liquid crystal alignment treatment agent is not particularly limited as long as it can dissolve specific compounds and polymers with specific structures. Among them, if the polymer is a polyimide precursor, polyimide, polyamide or polyester, or an acrylic polymer, methacrylic polymer, novolac resin, polyhydroxystyrene, cellulose or polysiloxane, etc., which has low solubility in the solvent, it is preferred to use the following solvent (also referred to as solvent A).

For example, 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, 4-hydroxy-4-methyl-2-pentanone, etc. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ-butyrolactone is preferably used. Moreover, these can be used alone or in combination.

If the polymer is an acrylic polymer, a methacrylic polymer, a novolac resin, a polyhydroxystyrene, a cellulose or a polysiloxane, and further, if the polymer is a polyimide precursor, a polyimide, a polyamide or a polyester, and the solubility of such polymer in the solvent is high, the following solvent (also referred to as solvent B) can be used.

Specific examples of solvent B include the solvent B described on pages 58 to 60 of International Publication WO2014/171493 (published on October 23, 2014). Among them, 1-hexanol, cyclohexanol, 1,2-ethylene glycol, 1,2-propylene glycol, propylene glycol monobutyl ether, ethylene glycol monobutyl ether, dipropylene glycol dimethyl ether, cyclohexanone, cyclopentanone or the aforementioned formula [D1] to formula [D3] are preferably used. In addition, when using the solvent B, in order to improve the coating properties of the liquid crystal alignment treatment agent, it is preferred to use the aforementioned solvent A in combination with N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ-butyrolactone. It is more preferably used in combination with γ-butyrolactone.

The solvents of type B are used to improve the coating properties or surface smoothness of the liquid crystal alignment film when the liquid crystal alignment treatment agent is applied. Therefore, if polyimide precursor, polyimide, polyamide or polyester is used in the polymer, it is better to use it in combination with the above-mentioned solvents of type A. At this time, the solvent of type B is preferably 1~99 mass% of the total solvent contained in the liquid crystal alignment treatment agent. Among them, 10~99 mass% is preferred. More preferably, it is 20~95 mass%. In order to improve the film strength of the liquid crystal alignment film, it is preferred to introduce a compound having at least one selected from an epoxy group, an isocyanate group, an oxycyclobutane group, a cyclic carbonate group, a hydroxyl group, a hydroxyl alkyl group, and a low-order alkoxyalkyl group (also collectively referred to as a specific crosslinking compound) into the liquid crystal alignment treatment agent. In this case, the compound must have two or more of these groups. Specific examples of crosslinking compounds having an epoxy group or an isocyanate group include the crosslinking compounds having an epoxy group or an isocyanate group described on pages 63 to 64 of the International Publication WO2014/171493 (published on October 23, 2014).

Specific examples of crosslinkable compounds having an oxacyclobutane group include crosslinkable compounds of formula [4a] to [4k] disclosed on pages 58 to 59 of International Publication WO2011/132751 (published on October 27, 2011).

Specific examples of the crosslinkable compound having a cyclic carbonate group include the crosslinkable compounds of formula [5-1] to formula [5-42] disclosed on pages 76 to 82 of International Publication WO2012/014898 (published on February 2, 2012).

Specific examples of crosslinking compounds having a hydroxyl group, a hydroxyalkyl group, and a lower alkoxyalkyl group include melamine derivatives or benzoguanamine derivatives described on pages 65 to 66 of International Publication No. 2014/171493 (published on October 23, 2014), and crosslinking compounds of formula [6-1] to formula [6-48] disclosed on pages 62 to 66 of International Publication No. WO2011/132751 (published on October 27, 2011).

The specific crosslinking compound used in the liquid crystal alignment treatment agent is preferably used in an amount of 0.1 to 100 parts by mass relative to 100 parts by mass of the total polymer component. In order to allow the crosslinking reaction to proceed and to exhibit the intended effect, it is preferably used in an amount of 0.1 to 50 parts by mass. It is particularly preferably used in an amount of 1 to 30 parts by mass. The liquid crystal alignment treatment agent preferably contains at least one generator selected from a photoradical generator, a photoacid generator, and a photobase generator (also referred to as a specific generator).

Specific examples of specific generators include those described on pages 54 to 56 of International Publication No. 2014/171493 (published on October 23, 2014). Among them, from the perspective of the adhesion between the liquid crystal layer and the liquid crystal alignment film, it is preferable to use a photoradical generator among the specific generators. The liquid crystal alignment treatment agent may include compounds that can improve the uniformity of the film thickness or the surface smoothness of the liquid crystal alignment film when the liquid crystal alignment treatment agent is applied. Furthermore, compounds that can improve the adhesion between the liquid crystal alignment film and the substrate may also be used. As compounds that can improve the uniformity of the film thickness or the surface smoothness of the liquid crystal alignment film, fluorine-based surfactants, silicone-based surfactants, or non-ionic surfactants may be cited. Specifically, the surfactant described on page 67 of International Publication WO2014/171493 (published on October 23, 2014) can be cited. Moreover, the usage ratio is preferably 0.01 to 2 parts by mass relative to 100 parts by mass of the total polymer component. More preferably, it is 0.01 to 1 part by mass.

Specific examples of compounds that can improve the adhesion between the liquid crystal alignment film and the substrate include the compounds described on pages 67 to 69 of International Publication WO2014/171493 (published on October 23, 2014). The usage ratio is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the total polymer component. More preferably, it is 1 to 20 parts by mass.

In addition to the aforementioned compounds, a dielectric or conductive substance may be added to the liquid crystal alignment treatment agent for the purpose of changing the electrical properties of the liquid crystal alignment film, such as the dielectric constant or conductivity. ＜Liquid crystal composition＞ The liquid crystal composition has a liquid crystal and a polymerizable compound. The liquid crystal may be a nematic liquid crystal, a lamellar liquid crystal or a cholesteric liquid crystal. In this case, the liquid crystal display element of the present invention preferably uses a liquid crystal having a negative dielectric anisotropy. In this case, from the perspective of low voltage drive and scattering characteristics, a liquid crystal having a large dielectric anisotropy and a large refractive index anisotropy is preferred. In addition, in accordance with the aforementioned physical property values of the phase transition temperature, dielectric anisotropy and refractive index anisotropy, two or more types of liquid crystals may be mixed and used in the liquid crystal. In order to drive a liquid crystal display element as an active element such as a TFT (Thin Film Transistor), the liquid crystal is required to have a high resistance and a high voltage holding ratio (also called VHR). Therefore, it is preferred to use a fluorine or chlorine liquid crystal that has a high resistance and whose VHR is not reduced by active energy rays such as ultraviolet rays.

Furthermore, the liquid crystal display element can also be made into a guest-host element by dissolving a dichroic dye in a liquid crystal composition. In this case, an element can be obtained that is transparent when no external voltage is applied and absorbs (scatters) when an external voltage is applied. In addition, in the liquid crystal display element, the direction of the director (direction of alignment) of the liquid crystal will change by 90 degrees due to the presence or absence of an external voltage. Therefore, the element can obtain a higher contrast than the previous guest-host element that switches between random alignment and vertical alignment by utilizing the difference in the light absorption characteristics of the dichroic dye. In addition, when the dichroic dye is dissolved, if the liquid crystal is aligned in the horizontal direction, it will become colored and will become opaque only in the scattered state. Therefore, it is also possible to obtain a device that switches from a colorless and transparent state when no external voltage is applied to a colored and opaque state as an external voltage is applied.

The polymerizable compound in the liquid crystal composition is used to form a polymer network (also called a curable resin) by polymerization reaction by active energy rays or heat during the production of liquid crystal display elements. The polymerization reaction in the present invention is preferably carried out by irradiation with ultraviolet rays. Although the polymerizable compound can be introduced into the liquid crystal composition in advance by polymerizing the polymerizable compound to obtain a polymer, from the perspective of the operation of the liquid crystal composition (i.e., suppressing the high viscosity of the liquid crystal composition or the solubility in the liquid crystal), it is better to use a liquid crystal composition containing a polymerizable compound. The polymerizable compound can be soluble in liquid crystal without any special limitation, but when the polymerizable compound is dissolved in the liquid crystal, there must be a temperature at which a part or the whole of the liquid crystal composition shows a liquid crystal phase. Even when a portion of the liquid crystal composition exhibits a liquid crystal phase, it is sufficient as long as the transparency and scattering characteristics of the entire element are roughly the same as when the liquid crystal display element is observed with the naked eye.

The polymerizable compound may be any compound that is polymerized by ultraviolet light or heat, and any reaction form may be used to polymerize the curable resin. Specific reaction forms include free radical polymerization, cationic polymerization, anionic polymerization, and polyaddition reaction.

Among them, from the viewpoint of the optical properties of the liquid crystal display element, the reaction form of the polymerizable compound is preferably free radical polymerization. At this time, as the polymerizable compound, the following free radical polymerizable compound or the oligomer can be used. In addition, as mentioned above, a polymer obtained by subjecting the polymerizable compound to polymerization reaction can also be used. Specific examples of free radical polymerizable compounds or the oligomers include free radical polymerizable compounds described on pages 69 to 71 of International Publication No. 2015/146987 (published on October 1, 2015).

The ratio of the free radical polymerizable compound or the oligomer used is preferably 70 to 150 parts by mass relative to 100 parts by mass of the liquid crystal in the liquid crystal composition from the viewpoint of the adhesion between the liquid crystal layer and the liquid crystal alignment film. It is more preferably 80 to 110 parts by mass. In addition, the free radical polymerizable compound can be used in one type or two or more types can be mixed for use according to various characteristics. In order to promote the free radical polymerization of the polymerizable compound, it is preferred to introduce a free radical initiator (also called a polymerization initiator) that generates free radicals by ultraviolet light into the liquid crystal composition. Specifically, the free radical initiator described on pages 71 to 72 of International Publication No. 2015/146987 (published on October 1, 2015) can be cited. The ratio of the free radical initiator used is preferably 0.01 to 20 parts by mass relative to 100 parts by mass of the liquid crystal in the liquid crystal composition from the viewpoint of adhesion between the liquid crystal layer and the liquid crystal alignment film. It is more preferably 0.05 to 10 parts by mass. In addition, the free radical initiator may be used in one type or in a mixture of two or more types depending on the characteristics.

It is preferred to introduce a compound of the following formula [5a] (also referred to as a specific liquid crystal additive compound) into the liquid crystal composition.

^S1 represents at least one structure selected from the following formulas [5-a] to [5-j]. Among them, formula [5-a], formula [5-b], formula [5-c], formula [5-d], formula [5-e] or formula [5-f] is preferred. From the viewpoint of adhesion between the liquid crystal layer and the liquid crystal alignment film, formula [5-a], formula [5-b], formula [5-c] or formula [5-e] is more preferred. Formula [5-a] or formula [5-b] is particularly preferred.

S ^A represents a hydrogen atom or a benzene ring. S ² represents at least one selected from a single bond, -O-, -NH-, -N(CH ₃ )-, -CH ₂ O-, -CONH-, -NHCO-, -CON(CH ₃ )-, -N(CH ₃ )CO-, -COO- and -OCO-. Among them, a single bond, -O-, -CH ₂ O-, -CONH-, -COO- or -OCO- is preferred. A single bond, -O-, -COO- or -OCO- is more preferred. S ³ represents a single bond or -(CH ₂ ) _a - (a is an integer of 1 to 15). Among them, a single bond or -(CH ₂ ) _a - (a is an integer of 1 to 10) is preferred. More preferably, it is -(CH ₂ ) _a - (a is an integer of 1 to 10). S ⁴ represents at least one selected from a single bond, -O-, -OCH ₂ -, -COO- and -OCO-. Among them, a single bond, -O- or -COO- is preferred. More preferably, it is -O-. S ⁵ represents a divalent cyclic group selected from a benzene ring, a cyclohexane ring and a heterocyclic ring, or a divalent organic group having 17 to 51 carbon atoms and a steroid skeleton, and any hydrogen atom on the aforementioned cyclic group may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorinated alkyl group having 1 to 3 carbon atoms, a fluorinated alkoxy group having 1 to 3 carbon atoms, or a fluorine atom. Among them, a benzene ring or a cyclohexane ring, or a divalent organic group having 17 to 51 carbon atoms with a steroid skeleton is preferred. A benzene ring or a divalent organic group having 17 to 51 carbon atoms with a steroid skeleton is more preferred. ^S6 represents at least one selected from a single bond, -O-, _-CH2- , _-OCH2- , _-CH2O- , -COO-, and -OCO-. Among them, a single bond, -O-, -COO-, or -OCO- is preferred. A single bond, -COO-, or -OCO- is more preferred. ^S7 represents a cyclic group selected from a benzene ring, a cyclohexane ring and a heterocyclic ring, and any hydrogen atom on the cyclic group can be substituted by an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorinated alkyl group having 1 to 3 carbon atoms, a fluorinated alkoxy group having 1 to 3 carbon atoms or a fluorinated atom. Among them, a benzene ring or a cyclohexane ring is preferred. ^S8 represents at least one selected from an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, a fluorinated alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms and a fluorinated alkoxy group having 1 to 18 carbon atoms. Among them, an alkyl group or an alkoxy group having 1 to 18 carbon atoms, or an alkenyl group having 2 to 18 carbon atoms is preferred. An alkyl group or an alkoxy group having 1 to 12 carbon atoms is further preferred. Sm represents an integer of 0 to 4. Among them, 0~2 are preferred. The specific liquid crystal additive compound has a rigid structure site such as a benzene ring or a cyclohexane ring, and a site represented by ^S1 in formula [5a] that undergoes polymerization reaction by ultraviolet light or heat. Therefore, when the specific liquid crystal additive compound is included in the liquid crystal composition, the rigid structure site of the specific liquid crystal additive compound will improve the vertical alignment of the liquid crystal and improve the transparency in the absence of an external voltage. In addition, the site of ^S1 in formula [5a] can maintain the polymer network in a tight state by reacting with a polymerizable compound. As more specific specific liquid crystal additive compounds, the compounds of the following formulas [5a-1] to [5a-11] can be cited, and it is preferred to use them.

^Sa represents -O- or -COO-. ^Sb represents an alkyl group having 1 to 12 carbon atoms. p1 represents an integer of 1 to 10. p2 represents an integer of 1 or 2.

^Sc represents a single bond, -COO- or -OCO-. ^Sd represents an alkyl group or an alkoxy group having 1 to 12 carbon atoms. p3 represents an integer of 1 to 10. p4 represents an integer of 1 or 2.

^Se represents -O- or -COO-. ^Sf represents a divalent organic group having 17 to 51 carbon atoms and a steroid skeleton. ^Sg represents an alkyl group having 1 to 12 carbon atoms or an alkenyl group having 2 to 18 carbon atoms. p5 represents an integer of 1 to 10. From the viewpoint of adhesion between the liquid crystal layer and the liquid crystal alignment film, the proportion of the specific liquid crystal additive compound used is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the liquid crystal in the liquid crystal composition. More preferably, it is 0.5 to 20 parts by mass. Particularly preferably, it is 1 to 10 parts by mass. In addition, the specific liquid crystal additive compound can be used in one type according to various characteristics, or two or more types can be mixed and used. As a method for adjusting the liquid crystal composition, there can be cited a method of mixing liquid crystal, a polymerizable compound and a specific liquid crystal additive compound together, or a method of pre-mixing a polymerizable compound with a specific liquid crystal additive compound and then mixing it with liquid crystal. Among them, the following method is preferred in the present invention: a method of pre-mixing a polymerizable compound with a specific liquid crystal additive compound and then mixing it with liquid crystal. When adjusting the liquid crystal composition as described above, heating may also be performed depending on the solubility of the polymerizable compound and the specific liquid crystal additive compound. The temperature at this time is preferably less than 100°C. <Method for producing a liquid crystal display element> As a substrate used for a liquid crystal display element, there is no particular limitation as long as it is a substrate with high transparency. In addition to glass substrates, plastic substrates such as acrylic substrates, polycarbonate substrates, and PET (polyethylene terephthalate) substrates can be used, and further films thereof can be used. Especially when used in dimming windows, etc., plastic substrates or films are preferred. Also, from the viewpoint of simplifying the process, it is preferred to use a substrate formed with ITO electrodes, IZO (Indium Zinc Oxide) electrodes, IGZO (Indium Gallium Zinc Oxide) electrodes, organic conductive films, etc. that are useful for liquid crystal driving. Also, when making a reflective liquid crystal display element, if only a single-sided substrate is used, a silicon wafer or a substrate formed with a metal or dielectric multilayer film such as aluminum can be used. The liquid crystal display element has a liquid crystal alignment film on at least one side of the substrate, and the liquid crystal alignment film is obtained by a liquid crystal alignment treatment agent containing a polymer having a specific compound and a specific structure. In particular, it is preferred that both substrates have a liquid crystal alignment film.

There is no particular limitation on the method for applying the liquid crystal alignment agent. Industrially, there are screen printing, flat plate printing, flexographic printing, inkjet printing, immersion printing, roll coating, slit coating, rotator coating, spraying, etc. The method can be appropriately selected according to the type of substrate or the thickness of the target liquid crystal alignment film.

After the liquid crystal alignment treatment agent is applied on the substrate, the solvent can be evaporated at a temperature of 30~300℃ (preferably 30~250℃) by heating means such as a heating plate, a heat circulation oven, an IR (infrared) oven, etc., depending on the type of substrate or the solvent used in the liquid crystal alignment treatment agent, to form a liquid crystal alignment film. In particular, if a plastic substrate is used as the substrate, it is preferably treated at a temperature of 30~150℃.

If the thickness of the liquid crystal alignment film after firing is too thick, it will be disadvantageous in terms of power consumption of the liquid crystal display element. If it is too thin, the reliability of the element will be reduced. Therefore, it is preferably 5 to 500 nm. It is more preferably 10 to 300 nm. It is particularly preferably 10 to 250 nm.

The liquid crystal composition used in the liquid crystal display element is the same as the liquid crystal composition described above, but a spacer for controlling the electrode gap (also called pitch) of the liquid crystal display element may also be introduced therein.

The method for injecting the liquid crystal composition is not particularly limited, and the following method can be cited as an example. That is, when a glass substrate is used as the substrate, a pair of substrates with a liquid crystal alignment film formed thereon is prepared, and a sealant is applied to the four sides of the substrate on one side by removing a portion, and then the substrate on the other side is bonded so that the surface of the liquid crystal alignment film becomes the inner side to produce an empty cell. In addition, a method can be cited in which a liquid crystal composition is injected into a cell by reducing the pressure from a place where the sealant is not applied. Furthermore, when a plastic substrate or a film is used as the substrate, a pair of substrates with a liquid crystal alignment film formed thereon is prepared, and a liquid crystal composition is dripped onto the substrate on one side by an ODF (One Drop Filling) method or an inkjet method, and then the substrate on the other side is bonded to obtain a cell with a liquid crystal composition injected therein. In the liquid crystal display element of the present invention, since the adhesion between the liquid crystal layer and the liquid crystal alignment film is high, it is not necessary to apply a sealant on the four sides of the substrate.

The pitch of the liquid crystal display element can be controlled by the aforementioned spacer, etc. As mentioned above, the method includes: a method of introducing a spacer of the intended size into the liquid crystal composition, or a method of using a substrate having a column spacer of the intended size, etc. In addition, if a plastic or film substrate is used as the substrate and the substrates are bonded by lamination, the pitch can be controlled without introducing a spacer.

The pitch of the liquid crystal display element is preferably 1 to 100 μm. More preferably, it is 1 to 50 μm. Particularly preferably, it is 2 to 30 μm. If the pitch is too small, the contrast of the liquid crystal display element will be reduced, and if it is too large, the driving voltage of the liquid crystal display element will be increased.

The liquid crystal display element is obtained as follows: a portion of the liquid crystal composition or the whole thereof is in a state of showing liquid crystal properties, and the liquid crystal composition is hardened to form a liquid crystal layer. The liquid crystal composition is injected into a cell and irradiated with ultraviolet light or heated to harden the liquid crystal composition. In the present invention, as mentioned above, ultraviolet light irradiation is preferred.

As a light source of the ultraviolet irradiation device used for ultraviolet irradiation, for example, a metal halogen lamp or a high-pressure mercury lamp can be cited. In addition, the wavelength of ultraviolet light is preferably 250~400nm. Among them, 310~370nm is preferred. In addition, heat treatment can also be performed after ultraviolet irradiation. As the temperature at this time, 40~120℃ is preferred. It is also preferred to be 40~80℃. As a device used for heating, a heating means used after applying the aforementioned liquid crystal alignment treatment agent on the substrate can be cited. In addition, the temperature at this time can be appropriately selected according to the reaction temperature of the polymerizable compound or the type of substrate. Specifically, 80℃~200℃ is preferred. [Example]

The present invention is described in more detail below by giving examples, but is not limited thereto. The abbreviations used below are as follows. "Specific compound"

"Compounds used in polyimide-based polymers" <Specific diamines (1)>

<Specific diamine (2)>

＜Other diamines＞

<Specific tetracarboxylic acid component>

"Cross-linked compounds"

"Solvent" NMP: N-methyl-2-pyrrolidone γ-BL: γ-butyrolactone BCS: Ethylene glycol monobutyl ether PB: Propylene glycol monobutyl ether PGME: Propylene glycol monomethyl ether "Compounds used in liquid crystal compositions" <Specified liquid crystal additive compounds>

<Polymerizable compounds> R1: IBXA (manufactured by Osaka Organic Chemical Industry Co., Ltd.) R2: KAYARAD FM-400 (manufactured by Nippon Kayaku Co., Ltd.) R3: KAYARAD HX-220 (manufactured by Nippon Kayaku Co., Ltd.) R4: EBECRYL 230 (manufactured by Daicel-allnex Co., Ltd.) R5: Karenz MT PE1 (manufactured by Showa Denko Co., Ltd.) <Photoradical initiator> P1: IRGACURE 184 (manufactured by BASF) <Liquid crystal> L1: MLC-6608 (manufactured by Merck) "Measurement of molecular weight of polyimide polymer" Using a room temperature gel permeation chromatography (GPC) apparatus (GPC-101) (manufactured by Showa Denko Co., Ltd.) and columns (KD-803, KD-805) (manufactured by Shodex Co., Ltd.), the measurement was performed in the following manner.

Column temperature: 50°C Solvent: N,N'-dimethylformamide (as additive, lithium bromide monohydrate (LiBr· _H2O ) is 30mmol/L (liter), phosphoric acid·anhydrous crystals (o-phosphoric acid) is 30mmol/L, tetrahydrofuran (THF) is 10ml/L) Flow rate: 1.0ml/min Standard samples for analysis curve preparation: TSK standard polyethylene oxide (molecular weight: about 900,000, 150,000, 100,000 and 30,000) (manufactured by Tosoh Corporation) and polyethylene glycol (molecular weight: about 12,000, 4,000 and 1,000) (manufactured by Polymer Laboratories). "Measurement of the imidization rate of polyimide-based polymers" 20 mg of polyimide powder was placed in an NMR (nuclear magnetic resonance) sample tube (NMR sampling tube stand, φ5 (manufactured by Kusano Scientific Co., Ltd.)), dimethyl sulfoxide deuteride (DMSO-d6, 0.05 mass% TMS (tetramethylsilane) mixture) (0.53 ml) was added, and ultrasonicated to completely dissolve it. The solution was measured by a 500 MHz proton NMR using an NMR measuring instrument (JNW-ECA500) (manufactured by JEOL DATUM). The imidization rate can be calculated by the following formula using the peak accumulation value of the proton derived from the structure that does not change before and after imidization as the reference proton and the peak accumulation value of the proton derived from the NH group of acylamidin appearing around 9.5ppm~10.0ppm.

Imidization rate (%) = (1-α·x/y)×100 (x is the peak accumulation value of protons from the NH group of acylamidin; y is the peak accumulation value of the reference proton; α is the ratio of the reference proton to the number of protons of one NH group of acylamidin when the polyacylamidin (acymidization rate is 0%)). "Synthesis of polyimide polymer" <Synthesis Example 1> D2 (1.02 g, 4.08 mmol), A1 (2.45 g, 6.42 mmol) and C1 (0.46 g, 4.25 mmol) were mixed in NMP (10.3 g) and reacted at 80°C for 4 hours. D1 (1.20 g, 6.12 mmol) and NMP (5.13 g) were added and reacted at 40°C for 6 hours to obtain a polyamide solution (1) having a resin solid concentration of 25% by mass. The number average molecular weight (also referred to as Mn) of the polyamide was 19,800, and the weight average molecular weight (also referred to as Mw) was 61,200. <Synthesis Example 2> D2 (1.11 g, 4.44 mmol), A1 (2.40 g, 6.31 mmol) and C1 (0.45 g, 4.16 mmol) were mixed in NMP (10.5 g) and reacted at 80°C for 4 hours. D1 (1.30 g, 6.63 mmol) and NMP (5.26 g) were added and reacted at 40°C for 6 hours to obtain a polyamine solution (2) having a resin solid content of 25% by mass. The polyamine had an Mn of 21,100 and an Mw of 63,500. <Synthesis Example 3> D2 (1.87 g, 7.47 mmol), A1 (4.06 g, 10.7 mmol) and B1 (1.88 g, 7.11 mmol) were mixed in NMP (20.0 g) and reacted at 80°C for 4 hours. D1 (2.20 g, 11.2 mmol) and NMP (10.0 g) were added and reacted at 40°C for 6 hours to obtain a polyamine solution (3) having a resin solid content of 25% by mass. The polyamine had an Mn of 18,800 and an Mw of 60,100. <Synthesis Example 4> NMP was added to the polyamide solution (3) (30.0 g) obtained by the method of Synthesis Example 3 and diluted to 6 mass %, and then acetic anhydride (2.50 g) and pyridine (1.50 g) were added as imidization catalysts, and the mixture was reacted at 60°C for 3 hours. The reaction solution was poured into methanol (450 ml), and the obtained precipitate was separated by filtration. The precipitate was washed with methanol and dried under reduced pressure at 100°C to obtain polyimide powder (4). The imidization rate of the polyimide was 55%, Mn was 16,900, and Mw was 44,200. <Synthesis Example 5> D4 (0.81 g, 4.09 mmol), A2 (1.53 g, 3.88 mmol) and B1 (1.54 g, 5.83 mmol) were mixed in γ-BL (10.2 g) and reacted at 60°C for 4 hours. Then, D1 (1.20 g, 6.12 mmol) and γ-BL (5.07 g) were added and reacted at 40°C for 8 hours to obtain a polyamine solution (5) having a resin solid content of 25% by mass. The polyamine had an Mn of 14,500 and an Mw of 45,100. <Synthesis Example 6> D4 (1.01 g, 5.10 mmol), A2 (2.29 g, 5.80 mmol) and B1 (1.02 g, 3.86 mmol) were mixed in γ-BL (10.7 g) and reacted at 60°C for 4 hours. Then, D1 (1.00 g, 5.10 mmol) and γ-BL (5.33 g) were added and reacted at 40°C for 8 hours to obtain a polyamine solution (6) having a resin solid content of 25% by mass. The polyamine had an Mn of 13,600 and an Mw of 43,900. <Synthesis Example 7> D4 (0.61 g, 3.08 mmol), A3 (1.68 g, 3.88 mmol) and B2 (1.18 g, 5.80 mmol) were mixed in γ-BL (9.73 g) and reacted at 60°C for 4 hours. Then, D1 (1.40 g, 7.14 mmol) and γ-BL (4.86 g) were added and reacted at 40°C for 8 hours to obtain a polyamine solution (7) having a resin solid content of 25% by mass. The polyamine had an Mn of 12,000 and an Mw of 40,100. <Synthesis Example 8> D3 (2.00 g, 8.92 mmol), A4 (1.67 g, 3.39 mmol) and B1 (1.34 g, 5.07 mmol) were mixed in γ-BL (15.0 g) and reacted at 40°C for 12 hours to obtain a polyamine solution (8) having a resin solid content of 25% by mass. The polyamine had an Mn of 10,300 and an Mw of 36,900. <Synthesis Example 9> D2 (1.11 g, 4.44 mmol), A5 (2.37 g, 6.29 mmol) and C1 (0.45 g, 4.16 mmol) were mixed in NMP (10.5 g) and reacted at 80°C for 4 hours. D1 (1.30 g, 6.63 mmol) and NMP (5.23 g) were added and reacted at 40°C for 6 hours to obtain a polyamide solution (9) having a resin solid content of 25% by mass. The polyamide had an Mn of 22,900 and an Mw of 65,700. <Synthesis Example 10> D2 (1.62 g, 6.47 mmol) and C1 (1.66 g, 15.4 mmol) were mixed in NMP (10.4 g) and reacted at 80°C for 4 hours, then D1 (1.90 g, 9.69 mmol) and NMP (5.17 g) were added and reacted at 40°C for 6 hours to obtain a polyamine solution (10) having a resin solid content of 25% by mass. The polyamine had an Mn of 28,300 and an Mw of 71,200.

Table 1 shows the polyimide polymers obtained in the synthesis examples.

*1: Polyamine. "Manufacturing of liquid crystal alignment treatment agent" <Example 1> T1 (0.13 g) and NMP (16.0 g) were added to the polyamine solution (1) (10.0 g) obtained by the method of Synthesis Example 1, and stirred at 25°C for 4 hours. Thereafter, BCS (15.7 g) was added, and stirred at 25°C for 6 hours to obtain a liquid crystal alignment treatment agent (1). The liquid crystal alignment treatment agent showed no abnormalities such as turbidity or precipitation, and was a uniform solution. <Example 2> T1 (0.13 g) and NMP (16.0 g) were added to the polyamine solution (2) (10.0 g) obtained by the method of Synthesis Example 2, and stirred at 25°C for 4 hours. Then, BCS (15.7 g) was added, and the mixture was stirred at 25°C for 6 hours to obtain a liquid crystal alignment treatment agent (2). The liquid crystal alignment treatment agent showed no abnormalities such as turbidity or precipitation, and was a uniform solution. <Example 3> T1 (0.13 g) and NMP (16.0 g) were added to the polyamine solution (3) (10.0 g) obtained by the method of Synthesis Example 3, and the mixture was stirred at 25°C for 4 hours. Then, BCS (15.7 g) was added, and the mixture was stirred at 25°C for 6 hours to obtain a liquid crystal alignment treatment agent (3). The liquid crystal alignment treatment agent showed no abnormalities such as turbidity or precipitation, and was a uniform solution. <Example 4> T1 (0.13 g) and NMP (16.0 g) were added to the polyamide solution (3) (10.0 g) obtained by the method of Synthesis Example 3, and stirred at 25°C for 4 hours. Then, K1 (0.13 g) and BCS (15.7 g) were added, and stirred at 25°C for 6 hours to obtain a liquid crystal alignment treatment agent (4). No abnormalities such as turbidity or precipitation were found in the liquid crystal alignment treatment agent, and it was a uniform solution. <Example 5> NMP (23.5 g) was added to the polyimide powder (4) (2.50 g) obtained by the method of Synthesis Example 4, and stirred at 70°C for 24 hours to dissolve it. Then, T1 (0.20 g), BCS (11.8 g) and PB (3.92 g) were added, and the mixture was stirred at 25°C for 6 hours to obtain a liquid crystal alignment treatment agent (5). The liquid crystal alignment treatment agent showed no abnormalities such as turbidity or precipitation, and was a uniform solution. <Example 6> γ-BL (7.83 g) was added to the polyimide powder (4) (2.50 g) obtained by the method of Synthesis Example 4, and the mixture was stirred at 70°C for 24 hours to dissolve it. Then, T1 (0.13 g) and PGME (31.3 g) were added, and the mixture was stirred at 25°C for 6 hours to obtain a liquid crystal alignment treatment agent (6). The liquid crystal alignment treatment agent showed no abnormalities such as turbidity or precipitation, and was a uniform solution. <Example 7> T1 (0.13 g) and γ-BL (0.33 g) were added to the polyamine solution (5) (10.0 g) obtained by the method of Synthesis Example 5, and stirred at 25°C for 4 hours. Thereafter, PGME (31.3 g) was added and stirred at 25°C for 6 hours to obtain a liquid crystal alignment treatment agent (7). The liquid crystal alignment treatment agent showed no abnormalities such as turbidity or precipitation, and was a uniform solution. <Example 8> T1 (0.13 g) and γ-BL (0.33 g) were added to the polyamine solution (5) (10.0 g) obtained by the method of Synthesis Example 5, and stirred at 25°C for 4 hours. Then, K2 (0.18 g) and PGME (31.3 g) were added, and stirred at 25°C for 6 hours to obtain a liquid crystal alignment treatment agent (8). No abnormalities such as turbidity or precipitation were found in the liquid crystal alignment treatment agent, and it was a uniform solution. <Example 9> T1 (0.18 g) and γ-BL (0.33 g) were added to the polyamine solution (6) (10.0 g) obtained by the method of Synthesis Example 6, and stirred at 25°C for 4 hours. Then, K2 (0.18 g) and PGME (31.3 g) were added, and the mixture was stirred at 25°C for 6 hours to obtain a liquid crystal alignment treatment agent (9). The liquid crystal alignment treatment agent showed no abnormalities such as turbidity or precipitation, and was a uniform solution. <Example 10> T1 (0.08 g) and γ-BL (0.33 g) were added to the polyamine solution (7) (10.0 g) obtained by the method of Synthesis Example 7, and the mixture was stirred at 25°C for 4 hours. Then, K2 (0.08 g) and PGME (31.3 g) were added, and the mixture was stirred at 25°C for 6 hours to obtain a liquid crystal alignment treatment agent (10). The liquid crystal alignment treatment agent showed no abnormalities such as turbidity or precipitation, and was a uniform solution. <Example 11> T1 (0.08 g) and γ-BL (0.33 g) were added to the polyamine solution (8) (10.0 g) obtained by the method of Synthesis Example 8, and stirred at 25°C for 4 hours. Thereafter, K2 (0.13 g) and PGME (31.3 g) were added, and stirred at 25°C for 6 hours to obtain a liquid crystal alignment treatment agent (11). The liquid crystal alignment treatment agent showed no abnormalities such as turbidity or precipitation, and was a uniform solution. <Example 12> T1 (0.13 g) and NMP (16.0 g) were added to the polyamine solution (9) (10.0 g) obtained by the method of Synthesis Example 9, and stirred at 25°C for 4 hours. Then, BCS (15.7 g) was added and stirred at 25°C for 6 hours to obtain a liquid crystal alignment treatment agent (12). No abnormalities such as turbidity or precipitation were found in the liquid crystal alignment treatment agent, and it was a uniform solution. <Comparative Example 1> NMP (16.0 g) and BCS (15.7 g) were added to the polyamine solution (1) (10.0 g) obtained by the method of Synthesis Example 1, and stirred at 25°C for 6 hours to obtain a liquid crystal alignment treatment agent (13). The liquid crystal alignment treatment agent showed no abnormalities such as turbidity or precipitation, and was a uniform solution. <Comparative Example 2> NMP (23.5 g), BCS (11.8 g) and PB (3.92 g) were added to the polyimide powder (4) (2.50 g) obtained by the method of Synthesis Example 4, and stirred at 25°C for 6 hours to obtain a liquid crystal alignment treatment agent (14). The liquid crystal alignment treatment agent showed no abnormalities such as turbidity or precipitation, and was a uniform solution. <Comparative Example 3> γ-BL (0.33 g) and PGME (31.3 g) were added to the polyamine solution (5) (10.0 g) obtained by the method of Synthesis Example 5, and the mixture was stirred at 25°C for 6 hours to obtain a liquid crystal alignment treatment agent (15). The liquid crystal alignment treatment agent showed no abnormalities such as turbidity or precipitation, and was a uniform solution. <Comparative Example 4> NMP (16.0 g) and BCS (15.7 g) were added to the polyamine solution (10) (10.0 g) obtained by the method of Synthesis Example 10, and the mixture was stirred at 25°C for 6 hours to obtain a liquid crystal alignment treatment agent (16). The liquid crystal alignment treatment agent showed no abnormalities such as turbidity or precipitation, and was a uniform solution. The liquid crystal alignment treatment agents obtained in the examples are shown in Tables 2 to 4.

*3: The values in parentheses indicate the amount of specific compound introduced (parts by mass) relative to 100 parts by mass of the polymer. *4: The values in parentheses indicate the amount of crosslinking compound introduced (parts by mass) relative to 100 parts by mass of the polymer. "Preparation of Liquid Crystal Composition" <Preparation of Liquid Crystal Composition (A)> R1 (1.30 g), R2 (1.50 g), R3 (0.60 g), R4 (0.90 g) and R5 (0.30 g) were mixed and stirred at 25°C for 6 hours to prepare a solution of a polymerizable compound. Thereafter, the prepared solution of the polymerizable compound, L1 (4.90 g) and P1 (0.50 g) were mixed and stirred at 25°C for 6 hours to obtain a liquid crystal composition (A). <Preparation of Liquid Crystal Composition (B)> R1 (1.00 g), R2 (1.30 g), R3 (0.60 g), R4 (0.90 g), R5 (0.30 g) and S1 (0.50 g) were mixed and stirred at 25°C for 2 hours to prepare a solution of a polymerizable compound. Thereafter, the prepared solution of a polymerizable compound, L1 (4.90 g) and P1 (0.50 g) were mixed and stirred at 25°C for 6 hours to obtain a liquid crystal composition (B). <Preparation of Liquid Crystal Composition (C)> R1 (1.00 g), R2 (1.30 g), R3 (0.60 g), R4 (0.90 g), R5 (0.30 g) and S2 (0.50 g) were mixed and stirred at 25°C for 2 hours to prepare a solution of a polymerizable compound. Thereafter, the prepared polymerizable compound solution, L1 (4.90 g) and P1 (0.50 g) were mixed and stirred at 25°C for 6 hours to obtain a liquid crystal composition (C). "Preparation of liquid crystal display element (glass substrate)" The liquid crystal alignment treatment agent obtained by the method of the above-mentioned embodiment and comparative example was pressure filtered using a thin film filter with a pore size of 1 μm. The obtained solution was applied by rotation on the ITO surface of a 100×100 mm glass substrate (length: 100 mm, width: 100 mm, thickness: 0.7 mm) with an ITO electrode that had been cleaned with pure water and IPA (isopropyl alcohol), and then heated on a hot plate at 100°C for 5 minutes and in a heat cycle clean oven at 210°C for 30 minutes to obtain an ITO substrate with a liquid crystal alignment film (film thickness 100 nm). Two ITO substrates with a liquid crystal alignment film were prepared, and a 10 μm spacer was applied on the liquid crystal alignment film surface of one of the substrates. Afterwards, the aforementioned liquid crystal composition (A) to (C) is dropped onto the liquid crystal alignment film surface of the substrate on which the spacer has been coated by the ODF (One Drop Filling) method, and then the liquid crystal alignment film surfaces of the other substrate are bonded together in a manner so as to be opposite to each other, thereby obtaining a liquid crystal display element before processing.

The liquid crystal display element before the treatment was irradiated with ultraviolet light for 60 seconds using a metal halogen lamp with an illumination of 9 mW/ ^cm2 , cutting off wavelengths below 350 nm. A liquid crystal display element (glass substrate) was obtained. "Preparation of liquid crystal display element (plastic substrate)" The liquid crystal alignment treatment agent obtained by the method of the above-mentioned embodiment and comparative example was pressure filtered using a thin film filter with a pore size of 1 μm. The obtained solution was applied by a bar coater onto the ITO surface of a 150×150 mm PET substrate with ITO electrodes (length: 150 mm, width: 150 mm, thickness: 0.1 mm) that had been washed with pure water, and then heated at 120°C for 2 minutes in a heat circulation oven to obtain an ITO substrate with a liquid crystal alignment film (film thickness 100 nm). Two ITO substrates with liquid crystal alignment films were prepared, and a 10 μm spacer was applied on the liquid crystal alignment film surface of one of the substrates. Afterwards, the aforementioned liquid crystal composition (A) to (C) is dripped onto the liquid crystal alignment film surface of the substrate coated with the spacer by the ODF (One Drop Filling) method, and then the liquid crystal alignment film surfaces of the other substrate are bonded so as to face each other, thereby obtaining a liquid crystal display element before treatment. When the liquid crystal composition is dripped and bonded by the ODF method, a glass substrate is used as a supporting substrate for the PET substrate with ITO electrodes. Afterwards, the supporting substrate is removed before irradiating with ultraviolet rays.

The liquid crystal display element before the treatment was irradiated with ultraviolet light in the same manner as in the aforementioned "Production of Liquid Crystal Display Element (Glass Substrate)" to obtain a liquid crystal display element (plastic substrate). "Evaluation of Optical Properties (Transparency and Scattering Properties)" This evaluation was conducted by measuring the Haze (fog) of the liquid crystal display element (glass substrate and plastic substrate) in the no-applied voltage state (0V) and the applied voltage state (AC drive: 10V~60V). At this time, the Haze was measured using a haze meter (HZ-V3, manufactured by SUGA Testing Instrument Co., Ltd.) in accordance with JIS K 7136. In this evaluation, the lower the Haze in the no-applied voltage state, the better the transparency, and the higher the Haze in the applied voltage state, the better the scattering properties.

In addition, as a stability test of the liquid crystal display element in a high temperature and high humidity environment, the measurement is also carried out after being stored in a constant temperature and humidity tank at a temperature of 80°C and a humidity of 90%RH for 24 hours. Specifically, the smaller the change in the haze after storage in the constant temperature and humidity tank compared to the initial haze, the better it is considered in this evaluation.

Furthermore, as a test of the stability of the liquid crystal display element to light irradiation, a desktop UV curing device (HCT3B28HEX-1) (manufactured by SEN LIGHT) was used to irradiate 5J/ ^cm2 of ultraviolet light (converted to 365nm) and observe. Specifically, the smaller the change in haze after ultraviolet irradiation compared to the initial haze, the better it is considered in this evaluation.

The measurement results of Haze at the initial stage, after storage in a constant temperature and humidity tank (constant temperature and humidity), and after UV irradiation (UV) are summarized in Tables 5 to 7. "Evaluation of the adhesion between the liquid crystal layer and the liquid crystal alignment film (liquid crystal alignment film and electrode)" This evaluation is carried out by storing the liquid crystal display element (glass substrate and plastic substrate) in a constant temperature and humidity tank at a temperature of 80°C and a humidity of 90%RH for 24 hours, and confirming the peeling and bubble presence of the liquid crystal display element (as a stability test of the liquid crystal display element in a high temperature and high humidity environment). Specifically, those that did not cause the peeling of the device (the liquid crystal layer and the liquid crystal alignment film, or the liquid crystal alignment film and the electrode were peeled off) and those that did not generate bubbles in the device were considered excellent in this evaluation (indicated as "good" in the table). At this time, in Examples 14 to 16, Example 20 and Example 21, in addition to the aforementioned standard test, as an emphasis test, they were also confirmed after being stored in a constant temperature and humidity tank at a temperature of 80°C and a humidity of 90%RH for 96 hours. The evaluation method is the same as above.

In addition, the liquid crystal display element was also irradiated with 5J/ ^cm2 of ultraviolet light (converted to 365nm) using a desktop UV curing device (HCT3B28HEX-1) (manufactured by SEN LIGHT) for confirmation (as a test of the stability of the liquid crystal display element to light irradiation). Specifically, those that did not cause the element to peel off and those that did not generate bubbles in the element were considered excellent in this evaluation (indicated as "good" in the table).

The results of the adhesion between the liquid crystal layer and the liquid crystal alignment film (liquid crystal alignment film and electrode) at the initial stage, after storage in a constant temperature and humidity tank (constant temperature and humidity), and after ultraviolet irradiation (ultraviolet) are summarized in Tables 8 to 10. <Example 14 to Example 26 and Comparative Example 5 to Comparative Example 8> Any of the liquid crystal alignment treatment agents (1) to (16) obtained by the methods of the aforementioned embodiments and comparative examples and the aforementioned liquid crystal compositions (A) to (C) were used to prepare liquid crystal display elements, evaluate optical properties (scattering properties and transparency), and evaluate the adhesion between the liquid crystal layer and the liquid crystal alignment film (liquid crystal alignment film and electrode) by the aforementioned method. At this time, Examples 14 to 18, Example 26, Comparative Example 5, Comparative Example 6 and Comparative Example 8 use glass substrates to manufacture and evaluate liquid crystal display elements, and Examples 19 to 25 and Comparative Example 7 use plastic substrates.

In addition, since the liquid crystal of Comparative Example 8 is not vertically aligned, each evaluation cannot be performed. Furthermore, in the evaluation of the adhesion between the liquid crystal layer and the liquid crystal alignment film (liquid crystal alignment film and electrode) in Examples 14 to 16, Example 20 and Example 21, in addition to the aforementioned standard test, a stress test is also performed at the same time. The stress test is an evaluation of 96 hours in a constant temperature and humidity tank at a temperature of 80°C and a humidity of 90%RH (other conditions are the same as the aforementioned conditions).

＊4: Measurement is not possible because the liquid crystal is not vertically aligned.

＊4: Measurement is not possible because the liquid crystal is not vertically aligned. ＊5: A very small amount of bubbles can be found in the device. ＊6: A small amount of bubbles can be found in the device (more than ＊5). ＊7: Bubbles can be found in the device (more than ＊6). ＊8: A large amount of bubbles can be found in the device (more than ＊7).

As described above, compared to the comparative example not using the liquid crystal alignment treatment agent containing a specific compound and a polymer having a specific structure (1), the change in Haze of the liquid crystal display element of the embodiment using the liquid crystal alignment treatment agent containing a specific compound and a polymer having a specific structure (1) after storage in a constant temperature and humidity tank and after ultraviolet irradiation is small. Moreover, even after storage in a constant temperature and humidity tank and after ultraviolet irradiation, the embodiment did not find the peeling of the liquid crystal display element or the generation of bubbles. Such results are the same even when a plastic substrate is used as the substrate of the liquid crystal display element. Specifically, such as the comparison between Example 14 and Comparative Example 5, the comparison between Example 18 and Comparative Example 6, and the comparison between Example 20 and Comparative Example 7. Furthermore, when a polyimide polymer is used in the polymer, the polymer terminal is a carboxylic acid or a dicarboxylic acid structure (that is, in the polymerization reaction of the diamine component and the tetracarboxylic acid component, the total molar number of the tetracarboxylic acid component is larger than the molar number of the diamine component), compared with the polymer terminal having an amino structure (in the aforementioned polymerization reaction, the total molar number of the tetracarboxylic acid component is smaller than the molar number of the diamine component), the generation of bubbles in the liquid crystal display element can be suppressed in the stress test. Specifically, when compared under the same conditions, such as the comparison between Example 14 and Example 15. Furthermore, when the specific diamine (1) having the structure of the aforementioned formula [2-1] is used in the specific structure (1), the change in Haze from the initial value after storage in a constant temperature and humidity tank and after ultraviolet irradiation is smaller than that of the diamine having the structure of the aforementioned formula [2-2]. Specifically, when the comparison is made under the same conditions, such as the comparison between Example 15 and Example 26. In addition, when the specific diamine (2) having the specific structure (2) is used in the polymer, the generation of bubbles in the liquid crystal display element can be suppressed in the stress test. Specifically, when the comparison is made under the same conditions, such as the comparison between Example 15 and Example 16.

In addition, when a specific cross-linking compound is introduced into the liquid crystal alignment treatment agent, the generation of bubbles in the liquid crystal display device can be suppressed in the stress test. Specifically, when comparing under the same conditions, such as the comparison between Example 20 and Example 21.

When a liquid crystal composition containing a specific liquid crystal additive compound is used, the transparency of the liquid crystal display element is higher (the haze is smaller when no external voltage is applied) and the driving voltage is lower than when the liquid crystal composition is not used. Specifically, when the same conditions are compared, such as the comparison between Example 21 and Example 22. [Industrial Applicability]

By using a liquid crystal alignment film obtained by using a liquid crystal alignment treatment agent containing a compound having a specific structure and a polymer having a specific structure, a liquid crystal display element can be obtained that can suppress the peeling of the element or the generation of bubbles and the reduction of optical properties even in a harsh environment of long-term, high temperature and high humidity or exposure to light.

Furthermore, the liquid crystal display element of the present invention is an inverted element that is suitable for use in a transparent state when no external voltage is applied and in a scattering state when a voltage is applied. Furthermore, the element can be used in a liquid crystal display for display purposes, and further, in a dimming window or light shutter element for controlling the blocking and penetration of light, and the substrate of the inverted element can be a plastic substrate.

The entire contents of the specification, patent application scope, and abstract of Japanese Patent Application No. 2019-034307 filed on February 27, 2019 are cited here and cited as the disclosure content of the specification of the present invention.

Claims (17)

A liquid crystal display element having a liquid crystal layer and a liquid crystal alignment film on at least one of the substrates, and a transmissive scattering type inverse liquid crystal display element which is transparent when no external voltage is applied and scattering when a voltage is applied, wherein the liquid crystal layer is formed by curing a liquid crystal composition comprising a liquid crystal and a polymerizable compound disposed between a pair of substrates having electrodes by applying at least one of active energy rays and heat, wherein the liquid crystal alignment film is obtained from a liquid crystal alignment treatment agent comprising the following components (A) and (B), wherein the component (A) is a compound of the following formula [1a], and the component (B) is a polymer having a structure of at least one selected from the following formulas [2-1] and [2-2], T ¹ -T ² -T ³ [1a] T ¹ represents at least one structure selected from the following formulas [1-a] to [1-h], ^T2 represents a single bond or an organic group having 1 to 18 carbon atoms, ^T3 represents the structure of the following formula [1],

T ^A represents an alkyl group with 1 to 3 carbon atoms,

* indicates the bonding site with ^T2 ,

^X1 represents at least one selected from a single bond, -( _CH2 ) _a- (a is an integer of 1 to 15), -O-, _-CH2O- , -CONH-, -NHCO-, -CON( _CH3 )-, -N( _CH3 )CO-, -COO- and -OCO-; ^X2 represents a single bond or -(CH2) _b- (b is an integer of 1 to 15); ^X3 represents at least one selected from a single bond, -( _CH2 ) _c- (c is an integer of 1 to 15), -O-, _-CH2O- , -COO- and -OCO-; _X ^X4 represents a divalent cyclic group selected from a benzene ring, a cyclohexane ring and a heterocyclic ring, or a divalent organic group having 17 to 51 carbon atoms and having a steroid skeleton, and any hydrogen atom on the aforementioned cyclic group may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorinated alkyl group having 1 to 3 carbon atoms, a fluorinated alkoxy group having 1 to 3 carbon atoms, or a fluorine atom, ^X5 represents a cyclic group selected from a benzene ring, a cyclohexane ring and a heterocyclic ring, and any hydrogen atom on the aforementioned cyclic group may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorinated alkyl group having 1 to 3 carbon atoms, a fluorinated alkoxy group having 1 to 3 carbon atoms, or a fluorine atom, Xn represents an integer of 0 to 4, and X ^X6 represents at least one selected from an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, a fluorinated alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, and ^a fluorinated alkoxy group having 1 to 18 carbon atoms; -X7 - ^X8 [2-2] ^X7 represents at least one selected from a single bond, -O-, _-CH2O- , -CONH-, -NHCO-, -CON( _CH3 )-, -N( _CH3 )CO-, -COO-, and -OCO-; and ^X8 represents an alkyl group having 8 to 22 carbon atoms or a fluorinated alkyl group having 6 to 18 carbon atoms. The liquid crystal display device of claim 1, wherein the polymer further has at least one structure selected from the following formulas [3-a] to [3-i],

^YA represents a hydrogen atom or a benzene ring. The liquid crystal display device of claim 1 or claim 2, wherein the liquid crystal alignment treatment agent further comprises a polymer having a structure selected from at least one of the following formulas [3-a] to [3-i],

^YA represents a hydrogen atom or a benzene ring. The liquid crystal display element of claim 1 or claim 2, wherein the polymer is selected from at least one of acrylic polymer, methacrylic polymer, novolac resin, polyhydroxystyrene, polyimide precursor, polyimide, polyamide, polyester, cellulose and polysiloxane. As in claim 4, the liquid crystal display element, wherein the aforementioned polymer is a polyimide precursor obtained by reacting a diamine component with a tetracarboxylic acid component, or a polyimide obtained by imidizing the polyimide precursor. A liquid crystal display element as claimed in claim 5, wherein the diamine component comprises a diamine having a structure selected from at least one of the above formulas [2-1] and [2-2]. The liquid crystal display device of claim 6, wherein the diamine is of the following formula [2a]:

X represents at least one structure selected from the above formula [2-1] and formula [2-2], and Xm represents an integer of 1 to 4. The liquid crystal display device of claim 5, wherein the diamine component comprises a diamine having a structure of the following formula [3]:

^Y1 represents at least one selected from a single bond, -O-, -NH-, -N(CH ₃ )-, -CH ₂ O-, -CONH-, -NHCO-, -CON(CH ₃ )-, -N(CH ₃ )CO-, -COO- and -OCO-; ^Y2 represents a single bond, an alkylene group having 1 to 18 carbon atoms, or an organic group having 6 to 24 carbon atoms having a cyclic group selected from a benzene ring, a cyclohexane ring and a heterocyclic ring, and any hydrogen atom on the cyclic group may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorinated alkyl group having 1 to 3 carbon atoms, a fluorinated alkoxy group having 1 to 3 carbon atoms or a fluorine atom; ^Y3 represents a single bond, -O-, -NH-, -N(CH ₃ )-, -CH ₂ O-, -CONH-, -NHCO-, -CON(CH ₃ )-, -N(CH ₃ )CO-, -COO- and -OCO-, Y ⁴ represents at least one structure selected from the above formula [3-a] to formula [3-i], and Yn represents an integer of 1 to 4. The liquid crystal display device of claim 8, wherein the diamine is of the following formula [3a]:

Y represents the structure of the above formula [3], and Ym represents an integer of 1 to 4. The liquid crystal display device of claim 5, wherein the tetracarboxylic acid component comprises tetracarboxylic dianhydride of the following formula [4]:

Z represents at least one structure selected from the following formula [4a] to formula [41],

Z ^A to Z ^D represent a hydrogen atom, a methyl group, a chlorine atom or a benzene ring, respectively, and Z ^E and Z ^F represent a hydrogen atom or a methyl group, respectively. As in claim 5, in the reaction between the diamine component and the tetracarboxylic acid component, when the total molar number of the diamine component is set to 1.0, the total molar number of the tetracarboxylic acid component is 1.05 to 1.20. The liquid crystal display device of claim 1 or claim 2, wherein the liquid crystal composition comprises a compound of the following formula [5a],

^S1 represents at least one structure selected from the following formulas [5-a] to [5-j], ^S2 represents at least one selected from a single bond, -O-, -NH-, -N(CH ₃ )-, -CH ₂ O-, -CONH-, -NHCO-, -CON(CH ₃ )-, -N(CH ₃ )CO-, -COO-, and -OCO-, ^S3 represents a single bond or -(CH ₂ ) _a - (a is an integer of 1 to 15), ^S4 represents at least one selected from a single bond, -O-, -OCH ₂ -, -COO-, and -OCO-, S ^S5 represents a divalent cyclic group selected from a benzene ring, a cyclohexane ring and a heterocyclic ring, or a divalent organic group having 17 to 51 carbon atoms and having a steroid skeleton, and any hydrogen atom on the aforementioned cyclic group may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorinated alkyl group having 1 to 3 carbon atoms, a fluorinated alkoxy group having 1 to 3 carbon atoms, or a fluorine atom, ^S6 represents at least one selected from a single bond, -O-, _-CH2- , _-OCH2- , _-CH2O- , -COO- and -OCO-, S ^S7 represents a cyclic group selected from a benzene ring, a cyclohexane ring and a heterocyclic ring, and any hydrogen atom on the cyclic group may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorinated alkyl group having 1 to 3 carbon atoms, a fluorinated alkoxy group having 1 to 3 carbon atoms or a fluorine atom, ^S8 represents at least one selected from an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, a fluorinated alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms and a fluorinated alkoxy group having 1 to 18 carbon atoms, and Sm represents an integer of 0 to 4,

^SA represents a hydrogen atom or a benzene ring. The liquid crystal display device of claim 12, wherein the compound of the formula [5a] is at least one selected from the following formulas [5a-1] to [5a-11],

^Sa represents -O- or -COO-, ^Sb represents an alkyl group having 1 to 12 carbon atoms, p1 represents an integer of 1 to 10, p2 represents an integer of 1 or 2,

^Sc represents a single bond, -COO- or -OCO-, ^Sd represents an alkyl group or alkoxy group having 1 to 12 carbon atoms, p3 represents an integer of 1 to 10, p4 represents an integer of 1 or 2,

^Se represents -O- or -COO-, ^Sf represents a divalent organic group having 17 to 51 carbon atoms and a steroid skeleton, ^Sg represents an alkyl group having 1 to 12 carbon atoms or an alkenyl group having 2 to 18 carbon atoms, and p5 represents an integer of 1 to 10. The liquid crystal display element of claim 1 or claim 2, wherein the liquid crystal alignment treatment agent further comprises a cross-linking compound having at least one selected from epoxy group, isocyanate group, cyclohexane group, cyclic carbonate group, hydroxyl group, hydroxyalkyl group and low-order alkoxyalkyl group. For example, the liquid crystal display element of claim 1 or claim 2, wherein the substrate of the liquid crystal display element is a glass substrate or a plastic substrate. A liquid crystal alignment film, which is used in a liquid crystal display element as in any one of claims 1 to 15, and is formed by a liquid crystal alignment treatment agent comprising the aforementioned (A) component and (B) component. A liquid crystal alignment treatment agent for forming a liquid crystal alignment film as claimed in claim 16, comprising the aforementioned (A) component and (B) component.