JP7424364B2 - Liquid crystal alignment treatment agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Description

The present invention relates to a transmission-scattering type reverse liquid crystal display element that is in a transparent state when no voltage is applied and becomes a scattering state when a voltage is applied.

A TN (Twisted Nematic) mode has been put into practical use as a liquid crystal display element. In this mode, it is necessary to use a polarizing plate to switch light using the optical rotation properties of liquid crystal. When a polarizing plate is used, the light utilization efficiency becomes low.

As a liquid crystal display element that does not use a polarizing plate, there is an element that switches between a transparent state (also referred to as a transparent state) and a scattering state of liquid crystal. In general, those using polymer dispersed liquid crystal (also referred to as PDLC (Polymer Dispersed Liquid Crystal)) and polymer network liquid crystal (PNLC (Polymer Network Liquid Crystal)) are known.
In these liquid crystal display elements, a liquid crystal composition containing a polymerizable compound that is polymerized by ultraviolet rays is placed between a pair of substrates equipped with electrodes, and the liquid crystal composition is cured by irradiation with ultraviolet rays. Form a composite with a cured product of the compound (for example, a polymer network). In this liquid crystal display element, the transmission state and scattering state of the liquid crystal are controlled by applying a voltage.
In conventional liquid crystal display devices using PDLC and PNLC, in most cases, when no voltage is applied, the liquid crystal molecules are oriented in random directions, resulting in a cloudy (scattering) state, and when a voltage is applied, the liquid crystals are aligned in the direction of the electric field. This is a normal type liquid crystal display element (also referred to as a normal type element) that transmits light and enters a transmissive state. However, with normal type elements, it is necessary to constantly apply a voltage to obtain a transparent state, so power consumption increases when used in applications that are often used in a transparent state, such as window glass. .
On the other hand, a reverse type liquid crystal display element (also referred to as a reverse type element) using PDLC, which is in a transparent state when no voltage is applied and is in a scattering state when a voltage is applied, has been proposed (see Patent Documents 1 and 2).

Japanese Patent No. 2885116 Japanese Patent No. 4132424

In a reverse type element, since the liquid crystal must be vertically aligned, a liquid crystal alignment film that vertically aligns the liquid crystal is used. However, since this liquid crystal alignment film is a highly hydrophobic film, the adhesion between the liquid crystal layer and the liquid crystal alignment film becomes low. Therefore, a large amount of polymerizable compound must be introduced into the liquid crystal composition used for the reverse type element in order to improve the adhesion between the liquid crystal layer and the liquid crystal alignment film. However, when a large amount of polymerizable compound is introduced, the vertical alignment of the liquid crystal is inhibited, and there is a problem that the transparency when no voltage is applied and the scattering properties when a voltage is applied are significantly reduced. Therefore, the liquid crystal alignment film used in the reverse type element needs to have a high vertical alignment property of liquid crystal.
Furthermore, reverse type devices are sometimes used by being attached to the window glass of automobiles and buildings, so even in harsh environments where they are exposed to high temperature, high humidity, and light irradiation for long periods of time, the vertical alignment of liquid crystals is difficult to maintain. It is necessary that the adhesion between the liquid crystal layer and the liquid crystal alignment film is high without deterioration.

Therefore, the present invention provides high vertical alignment of the liquid crystal, good optical properties, that is, good transparency when no voltage is applied, good scattering properties when no voltage is applied, and also good adhesion between the liquid crystal layer and the liquid crystal alignment film. It is an object of the present invention to provide a reverse type liquid crystal display element which can maintain these characteristics even in an environment where the liquid crystal display element has a high temperature and high humidity and is exposed to light irradiation for a long period of time.

As a result of intensive research to achieve the above object, the present inventor has completed the present invention having the following gist.
That is, it has a liquid crystal layer that is cured by applying at least one of active energy rays and heat to a liquid crystal composition containing a liquid crystal and a polymerizable compound, which is disposed between a pair of substrates provided with electrodes, and A transmission-scattering reverse type liquid crystal display element comprising a liquid crystal alignment film on at least one of the elements, and further comprising: a transparent state when no voltage is applied and a scattered state when a voltage is applied;
The liquid crystal display element is characterized in that the liquid crystal alignment film is obtained from a liquid crystal alignment treatment agent containing the following components (A) and (B).
Component (A): A compound having a group represented by the following formula [1] (also referred to as a specific compound).
Component (B): A polymer having at least one type of structure (also referred to as specific structure (1)) selected from the following formula [2-1] and formula [2-2].

* represents a binding site with another structure.

X ¹ is a single bond, -(CH ₂ ) _a - (a is an integer from 1 to 15), -O-, -CH ₂ O-, -CONH-, -NHCO-, -CON(CH ₃ ) -, -N(CH ₃ )CO-, -COO- and -OCO-. X ² represents a single bond or -(CH ₂ ) _b - (b is an integer from 1 to 15). X ³ represents at least one selected from a single bond, -(CH ₂ ) _c - (c is an integer from 1 to 15), -O-, -CH ₂ O-, -COO- and -OCO- show. X ⁴ represents at least one divalent cyclic group selected from a benzene ring, a cyclohexane ring, and a heterocycle, or a divalent organic group having 17 to 51 carbon atoms and having a steroid skeleton; The hydrogen atom is substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom. You can leave it there. X ⁵ represents at least one cyclic group selected from a benzene ring, a cyclohexane ring, and a heterocycle, and any hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms, or an alkyl group having 1 to 3 carbon atoms. may be substituted with an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom. Xn represents an integer from 0 to 4. X ⁶ is an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxyl group having 1 to 18 carbon atoms, and a fluorine-containing group having 1 to 18 carbon atoms. At least one type selected from alkoxyl groups is shown.

X ⁷ is a single bond, -O-, -CH ₂ O-, -CONH-, -NHCO-, -CON(CH ₃ )-, -N(CH ₃ )CO-, -COO- and -OCO- At least one selected type is shown. X ⁸ represents an alkyl group having 8 to 22 carbon atoms or a fluorine-containing alkyl group having 6 to 18 carbon atoms.

According to the present invention, the vertical alignment of the liquid crystal is high, the optical properties are good, that is, the transparency when no voltage is applied and the scattering properties when a voltage is applied, and furthermore, the liquid crystal layer and the liquid crystal alignment film are in close contact with each other. It is possible to obtain a reverse type liquid crystal display element that has high properties and can maintain these properties even in an environment where it is exposed to high temperature, high humidity, and light irradiation for a long time.
The mechanism by which a liquid crystal display element having the above-mentioned excellent characteristics can be obtained by the present invention is not necessarily clear, but it is estimated as follows.

The specific compound contained in the liquid crystal alignment treatment agent for producing the liquid crystal alignment film of the liquid crystal display element has a disulfide bond (SS) and a thioketone (C=S) group, so it is suitable for the liquid crystal alignment film and the metal electrode. The adhesion becomes higher. Furthermore, since the amino group (N) in the characteristic compound exhibits weak basicity, it is thought that the reaction of the polymerizable compound in the liquid crystal composition is promoted and a stronger polymer network can be formed.
Further, the liquid crystal aligning film of the present invention is obtained from a liquid crystal aligning agent containing a polymer having the specific structure (1) of the formula [2-1] or formula [2-2]. Since the specific structure (1) of formula [2-1] shows a rigid structure, a liquid crystal display element using a liquid crystal alignment film having this structure can obtain high and stable vertical alignment of liquid crystal. can. Therefore, it is considered that a reverse type element exhibiting good optical properties can be obtained, especially when the specific structure (1) of formula [2-1] is used.
Thus, a liquid crystal display element using a liquid crystal aligning agent containing a specific compound and a polymer having the specific structure (1) becomes a liquid crystal display element having the above characteristics. Therefore, the liquid crystal display element of the present invention can be used for a liquid crystal display for display purposes, a dimming window, an optical shutter element, etc. for controlling the blocking and transmission of light.

<Specific compound>
The specific compound is the compound of formula [1] above.
A specific example of the specific compound is the following formula [1a].

T ¹ represents at least one structure selected from the following formulas [1-a] to [1-h].

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

Among these, formula [1-b], formula [1-c] or formula [1-d] are preferred.
T ² represents a single bond or an organic group having 1 to 18 carbon atoms. Among these, a single bond or an organic group having 1 to 6 carbon atoms is preferred.
T ³ represents the structure of the above formula [1].

A more specific example of the specific compound is the following formula [1-1a], which is preferably used.

The proportion of the specific compound to be used is preferably 0.1 to 30 parts by mass based on 100 parts by mass of all the polymers from the viewpoint of adhesion between the liquid crystal alignment film and the metal electrode. More preferred is 0.5 to 20 parts by mass. Most preferred is 1 to 15 parts by weight. Further, the specific compound can be used alone or in combination of two or more types depending on each characteristic.
<Specific structure (1)>
The specific structure (1) is the structure of the above formula [2-1] or formula [2-2].
In formula [2-1], X ¹ to X ⁶ and Xn are as defined above, and among them, the following are preferable.
From the viewpoint of availability of raw materials and ease of synthesis, X ¹ is a single bond, -(CH ₂ ) _a - (a is an integer from 1 to 15), -O-, -CH ₂ O-, or - COO- is preferred. More preferred is a single bond, -(CH ₂ ) _a - (a is an integer from 1 to 10), -O-, -CH ₂ O- or -COO-.
X ² is preferably a single bond or -(CH ₂ ) _b - (b is an integer from 1 to 10).
From the viewpoint of ease of synthesis, X ³ is preferably a single bond, -(CH ₂ ) _a - (a is an integer from 1 to 15), -O-, -CH ₂ O-, or -COO-. More preferred is a single bond, -(CH ₂ ) _a - (a is an integer from 1 to 10), -O-, -CH ₂ O- or -COO-.
From the viewpoint of ease of synthesis, X ⁴ is preferably an organic group having 17 to 51 carbon atoms and having a benzene ring, a cyclohexane ring, or 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 fluorine-containing alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, or a fluorine-containing alkoxy group having 1 to 10 carbon atoms. More preferred is an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms. Particularly preferred are alkyl groups having 1 to 9 carbon atoms or alkoxy groups having 1 to 9 carbon atoms.
Xn is preferably 0 to 3 from the viewpoint of availability of raw materials and ease of synthesis. More preferred is 0-2.

Preferred combinations of X ¹ to X ⁶ and Xn are (2-1) to (2 -629). In addition, in each table of the International Publication Publication, X ¹ to X ⁶ in the present invention are shown as ^Y1 to ^Y6 , and Xn is shown as n. shall be read as Xn. In addition, in (2-605) to (2-629) published in each table of the International Publication Publication, the organic group having 17 to 51 carbon atoms having a steroid skeleton in the present invention is Although it is shown as an organic group having 25 carbon atoms, the organic group having 12 to 25 carbon atoms and having a steroid skeleton shall be read as the organic group having 17 to 51 carbon atoms having a steroid skeleton.

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

In formula [2-2], X ⁷ and X ⁸ are as defined above, and among them, the following are preferable.

X ⁷ is preferably a single bond, -O-, -CH ₂ O-, -CONH-, -CON(CH ₃ )- or -COO-. More preferred is a single bond, -O-, -CONH- or -COO-.
X ⁸ is preferably an alkyl group having 8 to 18 carbon atoms.

As the specific structure (1) in the present invention, as described above, it is preferable to use the structure of formula [2-1] from the viewpoint that high and stable vertical alignment of the liquid crystal can be obtained.
The specific structure (1) is preferably included in repeating units constituting the polymer. The repeating unit containing the specific structure (1) is preferably contained in an amount of 10 to 80 mol%, more preferably 20 to 70 mol%, based on the total repeating units constituting the polymer.
Further, the polymer having the specific structure (1) can be used alone or in combination of two or more types depending on each property.
<Specific structure (2)>
The polymer in the present invention preferably further has at least one structure (also referred to as specific structure (2)) selected from the following formulas [3-a] to [3-i].

Y ^A represents a hydrogen atom or a benzene ring.
Among these, formulas [3-a] to [3-f] are preferred. More preferred are formulas [3-a] to formula [3-e]. Particularly preferred are formula [3-a], formula [3-b], formula [3-d], or formula [3-e] from the viewpoint of adhesion between the liquid crystal layer and the liquid crystal alignment film.
The liquid crystal aligning agent in the present invention preferably further contains a polymer having the specific structure (2).
The specific structure (2) is preferably included in repeating units constituting the polymer. The repeating unit containing the specific structure (2) is preferably contained in an amount of 10 to 70 mol%, more preferably 20 to 60 mol%, based on the total repeating units constituting the polymer.
By using the specific structure (2), during the ultraviolet irradiation and heating steps when producing a liquid crystal display element, a photoreaction occurs with the reactive group of the polymerizable compound in the liquid crystal composition, and the liquid crystal layer and liquid crystal alignment film are bonded together. It is thought that the adhesion will be strong.
<Polymer>
The polymer is not particularly limited, but preferably at least one polymer selected from acrylic polymers, methacrylic polymers, novolac resins, polyhydroxystyrene, polyimide precursors, polyimides, polyamides, polyesters, cellulose, and polysiloxanes. More preferred are polyimide precursors or polyimides.
When a polyimide precursor or polyimide (also collectively referred to as a polyimide polymer) is used as the polymer, it is preferably a polyimide precursor or polyimide obtained by reacting a diamine component and a tetracarboxylic acid component.

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

R ¹ represents a tetravalent organic group. R ² represents a divalent organic group. A ¹ and A ² each represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. A ³ and A ⁴ each 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 is a tetracarboxylic acid compound, a tetracarboxylic dianhydride, a tetracarboxylic dihalide compound, or a tetracarboxylic acid compound. Examples include carboxylic acid dialkyl ester compounds and tetracarboxylic acid dialkyl ester dihalide compounds.

The polyimide polymer can be obtained relatively easily by using the tetracarboxylic dianhydride of the following formula [B] and the diamine of the following formula [C] as raw materials. Preferred is a polyamic acid having a structural formula of repeating units or a polyimide obtained by imidizing the polyamic acid.

R ¹ and R ² are the same as defined in formula [A].

R ¹ and R ² are the same as defined in formula [A].

Further, by a normal synthesis method, the above-obtained polymer of formula [D] is added with an alkyl group having 1 to 8 carbon atoms in A ¹ and A ² in formula [A] and It is also possible to introduce an alkyl group or acetyl group having 1 to 5 carbon atoms to A ³ and A ⁴ .
As a method for introducing the specific structure (1) into a polyimide polymer, it is preferable to use a diamine having the specific structure (1) as a part of the raw material. Among these, it is preferable to use a diamine (also referred to as specific diamine (1)) having at least one type of structure selected from the above formula [2-1] and formula [2-2].

In particular, it is preferable to use a diamine represented by the following formula [2a].

X represents at least one structure selected from the above formula [2-1] and formula [2-2]. Further, details of X ¹ to X ⁶ and Xn in formula [2-1] and preferred combinations are as in formula [2-1] above, and details of X ⁷ and X ⁸ in formula [2-2] , and preferred combinations are as shown in formula [2-2] above.
Xm represents an integer of 1 to 4. Among them, 1 or 2 is preferable.
Specific diamines (1) of formula [2-1] include formulas [2-1] to 15 described on pages 15 to 19 of International Publication WO2013/125595 (published on August 29, 2013). Examples include diamine compounds of formula [2-6] and formula [2-9] to formula [2-36]. In addition, in the description of International Publication WO2013/125595, R ₂ in formulas [2-1] to [2-3] and R ₄ in formulas [2-4] to [2-6] are carbon At least one selected from the group consisting of an alkyl group having 1 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, and a fluorine-containing alkoxy group having 1 to 18 carbon atoms. Furthermore, A ₄ in formula [2-13] represents a linear or branched alkyl group having 3 to 18 carbon atoms. In addition, R ₃ in formulas [2-4] to [2-6] represents at least one member selected from the group consisting of -O-, -CH ₂ O-, -COO-, and -OCO-. .

Among these, preferred diamines are formulas [2-1] to [2-6], formulas [2-9] to [2-13], or formula [2-22] described in International Publication No. WO2013/125595. ] to a diamine compound of formula [2-31].
More preferred are diamines of the following formulas [2a-32] to [2a-41] from the viewpoint of optical properties of the liquid crystal display element.

R ¹ and R ² each represent an alkyl group having 3 to 12 carbon atoms.

R ³ and R ⁴ each represent an alkyl group having 3 to 12 carbon atoms, and the cis-trans isomer of 1,4-cyclohexylene is a trans isomer.
Most preferred are the diamines of formulas [2a-35] to [2a-37], formula [2a-40], or formula [2a-41] from the viewpoint of optical properties of the liquid crystal display element.
Specific diamines (1) of formula [2-2] include formulas [DA1] to [DA11] described on page 23 of International Publication WO2013/125595 (published on August 29, 2013). Examples include diamine compounds. In the description of International Publication WO2013/125595, A ₁ in formulas [DA1] to [DA5] represents an alkyl group having 8 to 22 carbon atoms or a fluorine-containing alkyl group having 6 to 18 carbon atoms.
The proportion of the specific diamine (1) to be used is preferably 10 to 80 mol% based on the entire 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 preferred is 20 to 70 mol%. Further, the specific diamine (1) can be used alone or in combination of two or more types depending on each characteristic.
As a method for introducing the specific structure (2) into a polyimide polymer, it is preferable to use a diamine having the specific structure (2) as a part of the raw material. In particular, it is preferable to use a diamine having the structure of the following formula [3] (also referred to as specific diamine (2)).

Y ¹ is a single bond, -O-, -NH-, -N(CH ₃ )-, -CH ₂ O-, -CONH-, -NHCO-, -CON(CH ₃ )-, -N(CH ₃ ) represents at least one selected from CO-, -COO- and -OCO-. Among these, a single bond, -O-, -CH ₂ O-, -CONH-, -COO- or -OCO- is preferred. More preferred is a single bond, -O-, -CH ₂ O-, or -COO- from the viewpoint of availability of raw materials and ease of synthesis.
Y ² 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 heterocycle; The hydrogen atom is substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom. It's okay. Among these, a single bond, an alkylene group having 1 to 12 carbon atoms, a benzene ring, or a cyclohexane ring is preferred. More preferred is a single bond or an alkylene group having 1 to 12 carbon atoms from the viewpoint of adhesion between the liquid crystal layer and the liquid crystal alignment film.
Y ³ is a single bond, -O-, -NH-, -N(CH ₃ )-, -CH ₂ O-, -CONH-, -NHCO-, -CON(CH ₃ )-, -N(CH ₃ ) represents at least one selected from CO-, -COO- and -OCO-. Among these, a single bond, -O-, -COO- or -OCO- is preferred. More preferred is a single bond or -OCO-.
Y ⁴ represents at least one structure selected from the above formulas [3-a] to [3-i]. Among these, formulas [3-a] to [3-f] are preferred. More preferred are formulas [3-a] to formula [3-e]. Particularly preferred are formula [3-a], formula [3-b], formula [3-d], or formula [3-e] from the viewpoint of adhesion between the liquid crystal layer and the liquid crystal alignment film.
Yn represents an integer of 1 to 4. Among them, 1 or 2 is preferable.

It is preferable to use a diamine of the following formula [3a] as the specific diamine (2).

Y represents the structure of the above formula [3]. Further, details and preferred combinations of Y ¹ to X ⁴ and Xn in formula [3] are as in formula [3] above.
Ym represents an integer from 1 to 4. Among them, 1 is preferable.

More specific specific diamines (2) include the following formulas [3a-1] to [3a-12], and it is preferable to use these.

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 these, formula [3a-1], formula [3a-2], formula [3a-5] to formula [3a-7], formula [3a-11] or formula [3a-12] are preferred. More preferred are formulas [3a-5] to [3a-7], formula [3a-11], or formula [3a-12].
The proportion of the specific diamine (2) to be used is preferably 10 to 70 mol% based on 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 preferred is 20 to 60 mol%. Further, the specific diamine (2) can be used alone or in combination of two or more types depending on each characteristic.
Diamines other than the specific diamine (1) and specific diamine (2) (also referred to as other diamines) can also be used as the diamine component for producing the polyimide polymer.

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

In the present invention, it is preferable to use both the specific diamine (1) and the specific diamine (2) 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.
As the tetracarboxylic acid component for producing the polyimide polymer, the tetracarboxylic dianhydride of the following formula [4], its tetracarboxylic acid derivatives such as tetracarboxylic acid, tetracarboxylic dihalide, and dialkyl tetracarboxylate may be used. It is preferable to use an ester or a tetracarboxylic acid dialkyl ester dihalide (all of which are also collectively referred to as a specific tetracarboxylic acid component).

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

Z ^A to Z ^D each represent a hydrogen atom, a methyl group, a chlorine atom, or a benzene ring. Z ^E and Z ^F each represent a hydrogen atom or a methyl group.

Among them, Z in formula [4] is selected from formula [4a], formula [4c], formula [4d], and formula [4] from the viewpoint of ease of synthesis and ease of polymerization reactivity when producing a polymer. 4e], formula [4f], formula [4g], formula [4k], or formula [4l] are preferred. More preferred are formula [4a], formula [4e], formula [4f], formula [4g], formula [4k], or formula [4l]. Particularly preferred are formula [4a], formula [4e], formula [4f], formula [4g], or formula [4l] from the viewpoint of optical characteristics of the liquid crystal display element.
The usage ratio of the specific tetracarboxylic acid component is preferably 1 mol % or more based on the total tetracarboxylic acid component. More preferably, it is 5 mol% or more, and particularly preferably 10 mol% or more. The most preferable amount is 10 to 90 mol% from the viewpoint of optical properties of the liquid crystal display element.

Other tetracarboxylic acid components other than the specific tetracarboxylic acid component can be used in the polyimide polymer. Other tetracarboxylic acid components include the following tetracarboxylic acid compounds, tetracarboxylic dianhydrides, dicarboxylic acid dihalide compounds, dicarboxylic acid dialkyl ester compounds, and dialkyl ester dihalide compounds.
Specifically, other tetracarboxylic acid components described on pages 34 to 35 of International Publication WO2015/012368 (published on January 29, 2015) can be mentioned.
The specific tetracarboxylic acid component and other tetracarboxylic acid components can be used singly or in combination of two or more, depending on their respective properties.
The method for synthesizing the polyimide polymer is not particularly limited. It is usually obtained by reacting a diamine component and 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 mentioned.

The reaction between 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 at this time is not particularly limited as long as it dissolves the produced polyimide precursor.

Specifically, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide or 1,3-dimethyl-imidazolidone. Examples include non. In addition, when the polyimide precursor has high solvent solubility, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or the solvents of the following formulas [D1] to [D3] may be used. can.

D ¹ and D ² represent an alkyl group having 1 to 3 carbon atoms. D ³ represents an alkyl group having 1 to 4 carbon atoms.
Further, these may be used alone or in combination. Furthermore, even if the solvent does not dissolve the polyimide precursor, it may be mixed with the above solvent and used as long as the produced polyimide precursor does not precipitate. Further, since water in the organic solvent inhibits the polymerization reaction and further causes hydrolysis of the produced polyimide precursor, it is preferable to use an organic solvent that has been dehydrated and dried.
In the polymerization reaction of the polyimide precursor, the total number of moles of the tetracarboxylic acid component is preferably 0.8 to 1.2 when the total number of moles of the diamine component is 1.0. When the total number of moles of the tetracarboxylic acid component is smaller than 1.0, that is, when the total number of moles of the tetracarboxylic acid component is smaller than the number of moles of the diamine component, the terminal of the polymer becomes a structure of an amino group, and 1. When it is larger than 0, that is, when the total number of moles of the tetracarboxylic acid component is larger than the number of moles of the diamine component, the terminal of the polymer has a structure of carboxylic acid anhydride or dicarboxylic acid. In the present invention, since the effect of the specific compound becomes higher, the total number of moles of the tetracarboxylic acid component is larger than 1.0, that is, the total number of moles of the tetracarboxylic acid component is greater than the number of moles of the diamine component. It is preferable that it is also large. Specifically, when the total number of moles of the diamine component is 1.0, it is preferable that the total number of moles of the tetracarboxylic acid component is 1.05 to 1.20.

Polyimide is a polyimide obtained by ring-closing a polyimide precursor, and in this polyimide, the ring-closing rate (also referred to as imidization rate) of amic acid groups does not necessarily have to be 100%, and can vary depending on the use and purpose. It can be prepared arbitrarily. Among these, from the viewpoint of solubility of the polyimide polymer in the solvent, 30 to 80% is preferable. More preferred is 40 to 70%.

The molecular weight of the polyimide polymer is determined by Mw (weight average The molecular weight is preferably 5,000 to 1,000,000. More preferred is 10,000 to 150,000.
<Liquid crystal aligning agent>
The liquid crystal aligning agent contains a specific compound and a polymer having a specific structure (1), and is preferably a solution for forming a liquid crystal aligning film, and contains a specific compound and a polymer having a specific structure (1). It is a solution containing coalescence and solvent.

The content of the polymer component in the liquid crystal alignment treatment agent of the present invention can be appropriately changed depending on the thickness of the liquid crystal alignment film to be formed, but the point is that a uniform and defect-free liquid crystal alignment film is formed. From the viewpoint of storage stability of the solution, the content is preferably 1% by weight or more, and 10% by weight or less. Among these, 2 to 8% by weight is preferred, and 3 to 7% by weight is particularly preferred.
All of the polymer components contained in the liquid crystal aligning agent may be polymers having the specific structure (1), but in the present invention, as described above, the characteristic structure (1) and the specific structure (2) It is preferable to have both. At that time, even if one type of polymer having both specific structure (1) and specific structure (2) is used, the polymer having specific structure (1) and the polymer having specific structure (2) may be used. They may be used together. When used together, the proportion of the polymer having the specific structure (2) used is preferably 10 to 400 parts by weight based on 100 parts by weight of the polymer having the specific structure (1). More preferred is 50 to 200 parts by mass. One type or two or more types of polymers having the specific structure (2) can be used depending on each property.

Further, the polymer component may be a mixture of a polymer having the specific structure (1) and a polymer other than the polymer having the specific structure (2). In this case, the proportion of the polymer that does not have a specific structure used is preferably 10 to 200 parts by weight based on 100 parts by weight of all the polymers that have a specific structure. More preferred is 10 to 100 parts by mass.

The content of the solvent in the liquid crystal aligning agent can be appropriately selected from the viewpoint of the method of applying the liquid crystal aligning agent and obtaining the desired film thickness. Among these, from the viewpoint of forming a 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 preferred is 60 to 99% by mass. Particularly preferred is 65 to 99% by weight.

The solvent used for the liquid crystal aligning agent is not particularly limited as long as it is a solvent that dissolves a specific compound and a polymer having a specific structure. In particular, when the polymer is a polyimide precursor, polyimide, polyamide or polyester, or when the solubility of acrylic polymer, methacrylic polymer, novolak resin, polyhydroxystyrene, cellulose or polysiloxane in the solvent is low, the following solvents are used. (Also referred to as solvent A) is preferably used.

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, and the like. Among them, it is preferable to use N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ-butyrolactone. Further, these may be used alone or in combination.

When the polymer is an acrylic polymer, a methacrylic polymer, a novolac resin, a polyhydroxystyrene, a cellulose or a polysiloxane, it is further preferred that the polymer is a polyimide precursor, a polyimide, a polyamide or a polyester, and the incorporation of these polymers into a solvent When the solubility is high, the following solvents (also referred to as solvents B) can be used.

Specific examples of solvents B include solvents B described on pages 58 to 60 of International Publication No. WO2014/171493 (published on October 23, 2014). Among them, 1-hexanol, cyclohexanol, 1,2-ethanediol, 1,2-propanediol, propylene glycol monobutyl ether, ethylene glycol monobutyl ether, dipropylene glycol dimethyl ether, cyclohexanone, cyclopentanone or the above formula [D1] It is preferable to use the formula [D3].
In addition, when using these solvents B, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, or γ-butyrolactone, which are the solvents A, may be used in combination to improve the coating properties of the liquid crystal aligning agent. It is preferable to use it. More preferably, γ-butyrolactone is used in combination.

These solvents B can improve the coating properties and surface smoothness of the liquid crystal alignment film when applying the liquid crystal alignment treatment agent, so when a polyimide precursor, polyimide, polyamide or polyester is used as the polymer, It is preferable to use it in combination with the above-mentioned solvents A. In this case, the amount of solvent B is preferably 1 to 99% by mass of the total solvent contained in the liquid crystal aligning agent. Among these, 10 to 99% by mass is preferable. More preferred is 20 to 95% by mass.
The liquid crystal alignment agent has at least one selected from epoxy groups, isocyanate groups, oxetane groups, cyclocarbonate groups, hydroxy groups, hydroxyalkyl groups, and lower alkoxyalkyl groups in order to increase the film strength of the liquid crystal alignment film. It is preferable to introduce a compound (also collectively referred to as a specific crosslinkable compound). In that case, it is necessary to have two or more of these groups in the compound.
Specific examples of the crosslinkable compound having an epoxy group or isocyanate group include the crosslinkable compound having an epoxy group or isocyanate group described on pages 63 to 64 of International Publication Publication WO2014/171493 (published on October 23, 2014). Can be mentioned.

Specific examples of crosslinkable compounds having an oxetane group include crosslinkable compounds of formulas [4a] to [4k] listed on pages 58 to 59 of International Publication No. WO2011/132751 (published on October 27, 2011). Can be mentioned.

Specific examples of crosslinkable compounds having a cyclocarbonate group are formulas [5-1] to [5-42] listed on pages 76 to 82 of International Publication WO2012/014898 (published on February 2, 2012). Examples include crosslinking compounds.

Specific examples of crosslinkable 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 crosslinkable compounds of formulas [6-1] to [6-48], which are published on pages 62 to 66 of International Publication No. WO2011/132751 (published on October 27, 2011).

The proportion of the specific crosslinkable compound used in the liquid crystal aligning agent is preferably 0.1 to 100 parts by mass based on 100 parts by mass of all polymer components. More preferably, the amount is 0.1 to 50 parts by mass in order to allow the crosslinking reaction to proceed and develop the desired effect. Particularly preferred is 1 to 30 parts by weight.
It is preferable to introduce at least one kind of generator (also referred to as a specific generator) selected from a photoradical generator, a photoacid generator, and a photobase generator into the liquid crystal aligning agent.

Specific examples of the specific generator include those described on pages 54 to 56 of International Publication No. 2014/171493 (published on October 23, 2014). Among these, it is preferable to use a photoradical generator as the specific generator from the viewpoint of adhesion between the liquid crystal layer and the liquid crystal alignment film.
For the liquid crystal aligning agent, a compound that improves the uniformity of the film thickness and surface smoothness of the liquid crystal aligning film when the liquid crystal aligning agent is applied can be used. Furthermore, a compound that improves the adhesion between the liquid crystal alignment film and the substrate can also be used.
Examples of compounds that improve the uniformity of film thickness and surface smoothness of the liquid crystal alignment film include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants. Specifically, surfactants described on page 67 of International Publication WO2014/171493 (published on October 23, 2014) can be mentioned. Further, the usage ratio thereof is preferably 0.01 to 2 parts by weight based on 100 parts by weight of all polymer components. More preferred is 0.01 to 1 part by mass.

Specific examples of compounds that improve the adhesion between the liquid crystal alignment film and the substrate include compounds described on pages 67 to 69 of International Publication WO2014/171493 (published on October 23, 2014). Further, its usage ratio is preferably 0.1 to 30 parts by weight based on 100 parts by weight of all polymer components. More preferred is 1 to 20 parts by mass.

In addition to compounds other than those mentioned above, the liquid crystal aligning agent may contain a dielectric or a conductive substance for the purpose of changing the electrical properties such as the dielectric constant and conductivity of the liquid crystal aligning film.
<Liquid crystal composition>
The liquid crystal composition includes a liquid crystal and a polymerizable compound.
Nematic liquid crystal, smectic liquid crystal, or cholesteric liquid crystal can be used as the liquid crystal. In this case, it is preferable to use a liquid crystal having negative dielectric anisotropy for the liquid crystal display element in the present invention. In this case, from the viewpoint of low voltage driving and scattering properties, it is preferable to use a material having a large dielectric constant anisotropy and a large refractive index anisotropy. Furthermore, two or more types of liquid crystals can be used in combination, depending on the physical property values of the phase transition temperature, dielectric anisotropy, and refractive index anisotropy.
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 electrical resistance and a high voltage holding ratio (also referred to as VHR). Therefore, it is preferable to use a fluorine-based or chlorine-based liquid crystal, which has a high electrical resistance and whose VHR does not decrease due to active energy rays such as ultraviolet rays.

Furthermore, the liquid crystal display element can also be made into a guest-host type element by dissolving a dichroic dye in the liquid crystal composition. In this case, an element is obtained that is transparent when no voltage is applied and absorbs (scattering) when a voltage is applied. Further, in this liquid crystal display element, the direction of the liquid crystal director (orientation direction) changes by 90 degrees depending on whether or not a voltage is applied. Therefore, by utilizing the difference in light absorption properties of dichroic dyes, this device can achieve higher contrast than conventional guest-host devices that switch between random alignment and vertical alignment. Furthermore, when a dichroic dye is dissolved, the liquid crystal becomes colored when oriented in the horizontal direction, and becomes opaque only in the scattering state. Therefore, as voltage is applied, it is possible to obtain an element that switches from a colorless and transparent state when no voltage is applied to a colored and opaque state.

The polymerizable compound in the liquid crystal composition undergoes a polymerization reaction to form a polymer network (also referred to as a curable resin) by active energy rays and heat during production of the liquid crystal display element. The polymerization reaction in the present invention preferably proceeds by irradiation with ultraviolet rays.
As for the polymerizable compound, a polymer prepared by polymerizing the polymerizable compound may be introduced into the liquid crystal composition in advance. From the viewpoint of performance, it is preferable to use a liquid crystal composition containing a polymerizable compound.
The polymerizable compound is not particularly limited as long as it is dissolved in the liquid crystal, but when the polymerizable compound is dissolved in the liquid crystal, there must be a temperature at which a part or the entire liquid crystal composition exhibits a liquid crystal phase. Even if a part of the liquid crystal composition exhibits a liquid crystal phase, it is sufficient if the liquid crystal display element is visually checked to find that substantially uniform transparency and scattering properties are obtained throughout the element.

The polymerizable compound may be any compound that is polymerized by ultraviolet rays or heat, and the polymerization may proceed in any reaction manner to form a curable resin. Specific reaction formats include radical polymerization, cationic polymerization, anionic polymerization, and polyaddition reaction.

Among these, radical polymerization is preferable as the reaction type of the polymerizable compound from the viewpoint of optical properties of the liquid crystal display element. In this case, as the polymerizable compound, the following radical type polymerizable compounds or oligomers thereof can be used. Furthermore, as described above, a polymer obtained by subjecting these polymerizable compounds to a polymerization reaction can also be used.
Specific examples of radical-type polymerizable compounds or oligomers thereof include radical-type polymerizable compounds described on pages 69 to 71 of International Publication No. 2015/146987 (published on October 1, 2015).

The proportion of the radical type polymerizable compound or its oligomer used is preferably 70 to 150 parts by mass based on 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. More preferred is 80 to 110 parts by mass. Further, the radical type polymerizable compounds can be used alone or in combination of two or more types depending on the respective characteristics.
It is preferable to introduce a radical initiator (also referred to as a polymerization initiator) that generates radicals by ultraviolet rays into the liquid crystal composition for the purpose of promoting radical polymerization of a polymerizable compound.
Specifically, the radical initiator described on pages 71 to 72 of International Publication No. 2015/146987 (published on October 1, 2015) can be mentioned.
The proportion of the radical initiator to be used is preferably 0.01 to 20 parts by mass based on 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. More preferred is 0.05 to 10 parts by mass. Moreover, one type or a mixture of two or more types of radical initiators can be used depending on each characteristic.

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

S ¹ represents at least one structure selected from the following formulas [5-a] to [5-j]. Among these, formula [5-a], formula [5-b], formula [5-c], formula [5-d], formula [5-e], or formula [5-f] are preferred. More preferred are formula [5-a], formula [5-b], formula [5-c], or formula [5-e] from the viewpoint of adhesion between the liquid crystal layer and the liquid crystal alignment film. Particularly preferred is formula [5-a] or formula [5-b].

S ^A represents a hydrogen atom or a benzene ring.
S ² is a single bond, -O-, -NH-, -N(CH ₃ )-, -CH ₂ O-, -CONH-, -NHCO-, -CON(CH ₃ )-, -N(CH ₃ ) represents at least one selected from CO-, -COO- and -OCO-. Among these, a single bond, -O-, -CH ₂ O-, -CONH-, -COO- or -OCO- is preferred. More preferred is a single bond, -O-, -COO- or -OCO-.
S ³ represents a single bond or -(CH ₂ ) _a - (a is an integer from 1 to 15). Among these, a single bond or -(CH ₂ ) _a - (a is an integer from 1 to 10) is preferred. More preferred is -(CH ₂ ) _a - (a is an integer from 1 to 10).
S ⁴ represents at least one selected from a single bond, -O-, -OCH ₂ -, -COO-, and -OCO-. Among these, a single bond, -O- or -COO- is preferred. More preferred is -O-.
S ⁵ represents a divalent cyclic group selected from a benzene ring, a cyclohexane ring, and a heterocycle, or a divalent organic group having 17 to 51 carbon atoms and having a steroid skeleton, and any hydrogen atom on the cyclic group is , may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom. . Among these, a divalent organic group having 17 to 51 carbon atoms and having a benzene ring, a cyclohexane ring, or a steroid skeleton is preferred. More preferred is a divalent organic group having 17 to 51 carbon atoms and having a benzene ring or steroid skeleton.
S ⁶ represents at least one selected from a single bond, -O-, -CH ₂ -, -OCH ₂ -, -CH ₂ O-, -COO- and -OCO-. Among these, a single bond, -O-, -COO- or -OCO- is preferred. More preferred is a single bond, -COO- or -OCO-.
S ⁷ represents a cyclic group selected from a benzene ring, a cyclohexane ring, and a heterocycle, and any hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, It may be substituted with a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom. Among these, a benzene ring or a cyclohexane ring is preferred.
S ⁸ is an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, and a fluorine-containing group having 1 to 18 carbon atoms. At least one type selected from alkoxy groups is shown. Among these, an alkyl group or alkoxy group having 1 to 18 carbon atoms, or an alkenyl group having 2 to 18 carbon atoms is preferred. More preferred are alkyl groups or alkoxy groups having 1 to 12 carbon atoms.
Sm represents an integer from 0 to 4. Among these, 0 to 2 are preferred.
The specific liquid crystal additive compound has a rigid structural site such as a benzene ring or a cyclohexane ring, and a site that undergoes a polymerization reaction when exposed to ultraviolet rays or heat, which is represented by ^S1 in formula [5a]. Therefore, when a specific liquid crystal additive compound is included in a liquid crystal composition, the rigid structure portion of the specific liquid crystal additive compound can enhance the vertical alignment of the liquid crystal and increase the transparency when no voltage is applied. Moreover, the polymer network can be maintained in a dense state by reacting with the polymerizable compound at the S ¹ site in formula [5a].
More specific specific liquid crystal additive compounds include compounds of the following formulas [5a-1] to [5a-11], and it is preferable to use these.

S ^a each represents -O- or -COO-. Each S ^b represents an alkyl group having 1 to 12 carbon atoms. p1 each represents an integer from 1 to 10. p2 each represents an integer of 1 or 2.

S ^c each represents a single bond, -COO- or -OCO-. S ^d each represents an alkyl group or an alkoxy group having 1 to 12 carbon atoms. p3 each represents an integer from 1 to 10. p4 each represents an integer of 1 or 2.

S ^e each represents -O- or -COO-. S ^f each represents a divalent organic group having a steroid skeleton and having 17 to 51 carbon atoms. S ^g each represents an alkyl group having 1 to 12 carbon atoms or an alkenyl group having 2 to 18 carbon atoms. p5 each represents an integer from 1 to 10.
The proportion of the specific liquid crystal additive compound to be used is preferably 0.1 to 30 parts by mass based on 100 parts by mass of liquid crystal in the liquid crystal composition from the viewpoint of adhesion between the liquid crystal layer and the liquid crystal alignment film. More preferred is 0.5 to 20 parts by mass. Particularly preferred is 1 to 10 parts by weight. Further, the specific liquid crystal additive compound can be used alone or in combination of two or more types depending on each characteristic.
The liquid crystal composition may be prepared by mixing the liquid crystal, the polymerizable compound, and the specific liquid crystal additive compound together, or by mixing a mixture of the polymerizable compound and the specific liquid crystal additive compound in advance with the liquid crystal. There are several methods.
Among these, in the present invention, a method is preferred in which a mixture of a polymerizable compound and a specific liquid crystal additive compound is mixed in advance with the liquid crystal.
When preparing a liquid crystal composition as described above, heating may be performed depending on the solubility of the polymerizable compound and the specific liquid crystal additive compound. The temperature at that time is preferably less than 100°C.
<Method for manufacturing liquid crystal display element>
Substrates used for liquid crystal display elements are not particularly limited as long as they are highly transparent, and include glass substrates, plastic substrates such as acrylic substrates, polycarbonate substrates, PET (polyethylene terephthalate) substrates, and films thereof. can be used. In particular, plastic substrates and films are preferred when used for light control windows and the like. In addition, from the viewpoint of process simplification, it is preferable to use a substrate on which an ITO electrode, an IZO (Indium Zinc Oxide) electrode, an IGZO (Indium Gallium Zinc Oxide) electrode, an organic conductive film, etc. for driving the liquid crystal are formed. . Furthermore, in the case of a reflective liquid crystal display element, a silicon wafer, a metal such as aluminum, or a substrate on which a dielectric multilayer film is formed can be used as long as only one side of the substrate is used.
The liquid crystal display element has a liquid crystal alignment film obtained from a liquid crystal alignment treatment agent containing a specific compound and a polymer having a specific structure on at least one of the substrates. In particular, it is preferable that both substrates have liquid crystal alignment films.

The method for applying the liquid crystal aligning agent is not particularly limited, but industrially, there are screen printing, offset printing, flexo printing, inkjet method, dip method, roll coater method, slit coater method, spinner method, spray method, etc. can be appropriately selected depending on the type of substrate and the intended thickness of the liquid crystal alignment film.

After the liquid crystal aligning agent is applied onto the substrate, it is heated by a heating means such as a hot plate, thermal circulation type oven, or IR (infrared) type oven, depending on the type of substrate and the solvent used for the liquid crystal aligning agent. A liquid crystal alignment film can be obtained by evaporating the solvent at a temperature of 300°C, preferably 30 to 250°C. In particular, when a plastic substrate is used as the substrate, it is preferable to process at a temperature of 30 to 150°C.

The thickness of the liquid crystal alignment film after firing is preferably 5 to 500 nm, because if it is too thick, it will be disadvantageous in terms of power consumption of the liquid crystal display element, and if it is too thin, the reliability of the element may decrease. More preferred is 10 to 300 nm. Particularly preferred is 10 to 250 nm.

The liquid crystal composition used for the liquid crystal display element is the liquid crystal composition as described above, but a spacer can also be introduced therein to control the electrode gap (also referred to as the gap) of the liquid crystal display element.

The method for injecting the liquid crystal composition is not particularly limited, but examples include the following method. That is, when using a glass substrate as a substrate, a pair of substrates on which a liquid crystal alignment film is formed is prepared, a sealant is applied to four pieces of one substrate except for one part, and then the surface of the liquid crystal alignment film is coated with a sealant. Create an empty cell by attaching the other side of the substrate so that it is on the inside. Another method is to inject the liquid crystal composition under reduced pressure from a place where the sealant is not applied to obtain a liquid crystal composition injection cell. Furthermore, when using a plastic substrate or film as the substrate, a pair of substrates on which a liquid crystal alignment film is formed is prepared, and a liquid crystal composition is applied onto one of the substrates by an ODF (One Drop Filling) method or an inkjet method. A method for obtaining a liquid crystal composition injected cell is by dropping the liquid crystal composition dropwise and then bonding the other side of the substrate. In the liquid crystal display element of the present invention, since the adhesiveness between the liquid crystal layer and the liquid crystal alignment film is high, it is not necessary to apply a sealant to the four pieces of the substrate.

The gap of the liquid crystal display element can be controlled using the spacer or the like. Examples of this method include, as described above, a method of introducing a spacer of a desired size into a liquid crystal composition, a method of using a substrate having a column spacer of a desired size, and the like. Furthermore, when a plastic or film substrate is used as the substrate and the substrates are laminated together, the gap can be controlled without introducing a spacer.

The gap size of the liquid crystal display element is preferably 1 to 100 μm. More preferred is 1 to 50 μm. Particularly preferred is 2 to 30 μm. If the gap is too small, the contrast of the liquid crystal display element will decrease, and if it is too large, the driving voltage of the liquid crystal display element will increase.

A liquid crystal display element is obtained by curing a liquid crystal composition to form a liquid crystal layer in a state where a part or the whole of the liquid crystal composition exhibits liquid crystallinity. The liquid crystal composition is cured by irradiating the liquid crystal composition injection cell with ultraviolet rays or heating it. In the present invention, as described above, irradiation with ultraviolet light is preferred.

Examples of the light source of the ultraviolet irradiation device used for ultraviolet irradiation include a metal halide lamp or a high-pressure mercury lamp. Further, the wavelength of the ultraviolet rays is preferably 250 to 400 nm. Among these, 310 to 370 nm is preferred. Further, heat treatment may be performed after irradiation with ultraviolet rays. The temperature at that time is preferably 40 to 120°C. More preferred is 40 to 80°C.
Examples of the device used for heating include heating means used after applying the liquid crystal aligning agent onto the substrate. Further, the temperature at that time is appropriately selected depending on the temperature at which the reaction of the polymerizable compound proceeds and the type of substrate. Specifically, the temperature is preferably 80°C to 200°C.

The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited thereto.
The abbreviations used below are as follows.
"Specific compound"

"Compounds used in polyimide polymers"
<Specific diamine (1)>

<Specific diamine (2)>

<Other diamines>

<Specific tetracarboxylic acid component>

"Crosslinkable compound"

"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"
<Specific liquid crystal additive compound>

<Polymerizable compound>
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)
R5: Karenz MT PE1 (manufactured by Showa Denko)
<Photoradical initiator>
P1: IRGACURE 184 (manufactured by BASF)
<Liquid crystal>
L1: MLC-6608 (manufactured by Merck & Co.)
"Molecular weight measurement of polyimide polymers"
It was measured as follows using a room temperature gel permeation chromatography (GPC) device (GPC-101) (manufactured by Showa Denko) and columns (KD-803, KD-805) (manufactured by Shodex).

Column temperature: 50℃
Eluent: N,N'-dimethylformamide (as additives, 30 mmol/L (liter) of lithium bromide-hydrate (LiBr.H ₂ O), 30 mmol of phosphoric acid/anhydrous crystal (o-phosphoric acid) /L, tetrahydrofuran (THF) 10ml/L)
Flow rate: 1.0 ml/min Standard sample for creating a calibration curve: TSK standard polyethylene oxide (molecular weight: approx. 900,000, 150,000, 100,000 and 30,000) (manufactured by Tosoh Corporation) and polyethylene glycol (molecular weight: approx. 12,000, 4,000 and 1,000) (manufactured by Polymer Laboratory).
"Measurement of imidization rate of polyimide polymer"
Put 20 mg of polyimide powder into an NMR (nuclear magnetic resonance) sample tube (NMR sampling tube standard, φ5 (manufactured by Kusano Kagaku)) and add deuterated dimethyl sulfoxide (DMSO-d6, 0.05% by mass TMS (tetramethylsilane)). Mixed product) (0.53 ml) was added and completely dissolved by applying ultrasound. This solution was subjected to proton NMR measurement at 500 MHz using an NMR measuring device (JNW-ECA500) (manufactured by JEOL Datum). The imidization rate is determined using a proton derived from a structure that does not change before and after imidization as a reference proton, and the peak integrated value of this proton and the proton peak derived from the NH group of the amic acid that appears around 9.5 ppm to 10.0 ppm. It was calculated using the following formula using the integrated value.

Imidization rate (%) = (1-α・x/y)×100
(x is the integrated value of the proton peak derived from the NH group of amic acid, y is the integrated peak value of the reference proton, and α is the reference proton for one NH group proton of the amic acid in the case of polyamic acid (imidization rate is 0%) )
"Synthesis of polyimide polymer"
<Synthesis example 1>
D2 (1.02g, 4.08mmol), A1 (2.45g, 6.42mmol) and C1 (0.46g, 4.25mmol) were mixed in NMP (10.3g) and reacted at 80°C for 4 hours. After that, 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 polyamic acid solution (1) with a resin solid content concentration of 25% by mass. . The number average molecular weight (also referred to as Mn) of this polyamic acid 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. After that, 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 polyamic acid solution (2) with a resin solid content concentration of 25% by mass. . This polyamic acid had Mn of 21,100 and Mw of 63,500.
<Synthesis example 3>
D2 (1.87g, 7.47mmol), A1 (4.06g, 10.7mmol) and B1 (1.88g, 7.11mmol) were mixed in NMP (20.0g) and reacted at 80°C for 4 hours. After that, 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 polyamic acid solution (3) with a resin solid content concentration of 25% by mass. . This polyamic acid had Mn of 18,800 and Mw of 60,100.
<Synthesis example 4>
After adding NMP to the polyamic acid solution (3) (30.0 g) obtained by the method of Synthesis Example 3 and diluting it to 6% by mass, acetic anhydride (2.50 g) and pyridine (1.50 g) were added as an imidization catalyst. ) was added and reacted at 60°C for 3 hours. This reaction solution was poured into methanol (450 ml), and the resulting precipitate was filtered off. This precipitate was washed with methanol and dried under reduced pressure at 100°C to obtain polyimide powder (4). The imidization rate of this 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 incubated at 60°C for 4 After reacting for an hour, D1 (1.20 g, 6.12 mmol) and γ-BL (5.07 g) were added and reacted at 40°C for 8 hours. ) was obtained. This polyamic acid had Mn of 14,500 and 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 incubated at 60°C for 4 hours. After reacting for an hour, D1 (1.00 g, 5.10 mmol) and γ-BL (5.33 g) were added and reacted at 40°C for 8 hours. ) was obtained. This polyamic acid had Mn of 13,600 and 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 incubated at 60°C for 4 After reacting for an hour, D1 (1.40 g, 7.14 mmol) and γ-BL (4.86 g) were added and reacted at 40°C for 8 hours. ) was obtained. This polyamic acid had Mn of 12,000 and 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 heated at 40°C for 12 The reaction was carried out for a period of time to obtain a polyamic acid solution (8) having a resin solid content concentration of 25% by mass. This polyamic acid had Mn of 10,300 and 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. After that, 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 polyamic acid solution (9) with a resin solid content concentration of 25% by mass. . This polyamic acid had Mn of 22,900 and 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 polyamic acid solution (10) with a resin solid content concentration of 25% by mass. This polyamic acid had Mn of 28,300 and Mw of 71,200.

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

*1: Polyamic acid.
"Manufacture of liquid crystal aligning agent"
<Example 1>
T1 (0.13 g) and NMP (16.0 g) were added to the polyamic acid solution (1) (10.0 g) obtained by the method of Synthesis Example 1, and the mixture was 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 aligning agent (1). This liquid crystal aligning agent had 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 polyamic acid solution (2) (10.0 g) obtained by the method of Synthesis Example 2, and the mixture was 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 aligning agent (2). This liquid crystal aligning agent had 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 polyamic acid 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 stirred at 25° C. for 6 hours to obtain a liquid crystal aligning agent (3). This liquid crystal aligning agent had 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 polyamic acid 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, K1 (0.13 g) and BCS (15.7 g) were added and stirred at 25° C. for 6 hours to obtain a liquid crystal aligning agent (4). This liquid crystal aligning agent had no abnormalities such as turbidity or precipitation, and was a uniform solution.
<Example 5>
NMP (23.5 g) was added to polyimide powder (4) (2.50 g) obtained by the method of Synthesis Example 4, and dissolved by stirring at 70° C. for 24 hours. Then, T1 (0.20 g), BCS (11.8 g) and PB (3.92 g) were added and stirred at 25° C. for 6 hours to obtain a liquid crystal aligning agent (5). This liquid crystal aligning agent had no abnormalities such as turbidity or precipitation, and was a uniform solution.
<Example 6>
γ-BL (7.83 g) was added to polyimide powder (4) (2.50 g) obtained by the method of Synthesis Example 4, and dissolved by stirring at 70° C. for 24 hours. Then, T1 (0.13 g) and PGME (31.3 g) were added and stirred at 25° C. for 6 hours to obtain a liquid crystal aligning agent (6). This liquid crystal aligning agent had 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 polyamic acid solution (5) (10.0 g) obtained by the method of Synthesis Example 5, and the mixture was stirred at 25° C. for 4 hours. Then, PGME (31.3 g) was added and stirred at 25° C. for 6 hours to obtain a liquid crystal aligning agent (7). This liquid crystal aligning agent had 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 polyamic acid solution (5) (10.0 g) obtained by the method of Synthesis Example 5, and the mixture was 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 aligning agent (8). This liquid crystal aligning agent had no abnormalities such as turbidity or precipitation, and was a uniform solution.
<Example 9>
T1 (0.18 g) and γ-BL (0.33 g) were added to the polyamic acid solution (6) (10.0 g) obtained by the method of Synthesis Example 6, and the mixture was 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 aligning agent (9). This liquid crystal aligning agent had no abnormalities such as turbidity or precipitation, and was a uniform solution.
<Example 10>
To the polyamic acid solution (7) (10.0 g) obtained by the method of Synthesis Example 7, T1 (0.08 g) and γ-BL (0.33 g) were added and stirred at 25° C. for 4 hours. Then, K2 (0.08 g) and PGME (31.3 g) were added and stirred at 25° C. for 6 hours to obtain a liquid crystal aligning agent (10). This liquid crystal aligning agent had no abnormalities such as turbidity or precipitation, and was a uniform solution.
<Example 11>
To the polyamic acid solution (8) (10.0 g) obtained by the method of Synthesis Example 8, T1 (0.08 g) and γ-BL (0.33 g) were added and stirred at 25° C. for 4 hours. Then, K2 (0.13 g) and PGME (31.3 g) were added and stirred at 25° C. for 6 hours to obtain a liquid crystal aligning agent (11). This liquid crystal aligning agent had 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 polyamic acid solution (9) (10.0 g) obtained by the method of Synthesis Example 9, and the mixture was 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 aligning agent (12). This liquid crystal aligning agent had no abnormalities such as turbidity or precipitation, and was a uniform solution.
<Comparative example 1>
NMP (16.0 g) and BCS (15.7 g) were added to the polyamic acid solution (1) (10.0 g) obtained by the method of Synthesis Example 1, and the mixture was stirred at 25° C. for 6 hours to perform liquid crystal alignment treatment. Agent (13) was obtained. This liquid crystal aligning agent had 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 polyimide powder (4) (2.50 g) obtained by the method of Synthesis Example 4, and the mixture was stirred at 25°C for 6 hours. Thus, a liquid crystal aligning agent (14) was obtained. This liquid crystal aligning agent had 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 polyamic acid 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 form a liquid crystal. An alignment treatment agent (15) was obtained. This liquid crystal aligning agent had 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 polyamic acid 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 undergo liquid crystal alignment treatment. Agent (16) was obtained. This liquid crystal aligning agent had no abnormalities such as turbidity or precipitation, and was a uniform solution.
The liquid crystal aligning agents obtained in Examples are shown in Tables 2 to 4.

*3: The numerical value in parentheses indicates the amount (parts by mass) of the specific compound introduced relative to 100 parts by mass of the polymer.
*4: The numerical value in parentheses indicates the amount (parts by mass) of the crosslinkable compound introduced relative to 100 parts by mass of the polymer.
"Preparation of liquid crystal composition"
<Preparation of liquid crystal composition (A)>
R1 (1.30g), R2 (1.50g), R3 (0.60g), R4 (0.90g) and R5 (0.30g) were mixed and stirred at 25°C for 6 hours to form a polymerizable compound. A solution was prepared. Thereafter, the solution of the prepared 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)>
Mix R1 (1.00g), R2 (1.30g), R3 (0.60g), R4 (0.90g), R5 (0.30g) and S1 (0.50g) and heat at 25°C for 2 hours. A solution of the polymerizable compound was prepared by stirring. Thereafter, the solution of the polymerizable compound prepared, 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)>
Mix R1 (1.00g), R2 (1.30g), R3 (0.60g), R4 (0.90g), R5 (0.30g) and S2 (0.50g) and heat at 25°C for 2 hours. A solution of the polymerizable compound was prepared by stirring. 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 (C).
"Fabrication of liquid crystal display element (glass substrate)"
The liquid crystal aligning agents obtained by the methods of the Examples and Comparative Examples were filtered under pressure using a membrane filter with a pore diameter of 1 μm. The obtained solution was spin-coated on the ITO surface of a 100 x 100 mm glass substrate with an ITO electrode (length: 100 mm, width: 100 mm, thickness: 0.7 mm), which had been washed with pure water and IPA (isopropyl alcohol). Heat treatment was performed at 100° C. for 5 minutes on a hot plate and at 210° C. for 30 minutes in a thermal circulation clean oven to obtain an ITO substrate with a liquid crystal alignment film having a film thickness of 100 nm. Two ITO substrates with the liquid crystal alignment film were prepared, and a 10 μm spacer was applied to the surface of the liquid crystal alignment film of one of the substrates. Thereafter, the liquid crystal compositions (A) to (C) are dropped by the ODF (One Drop Filling) method onto the liquid crystal alignment film surface of the other substrate coated with the spacer, and then the liquid crystal alignment film surface of the other substrate is coated with the liquid crystal alignment film surface. They were bonded so that they faced each other, and an unprocessed liquid crystal display element was obtained.

The liquid crystal display element before this treatment was irradiated with ultraviolet light using a metal halide lamp with an illuminance of 9 mW/cm ² to cut wavelengths of 350 nm or less and for an irradiation time of 60 seconds. Thereby, a liquid crystal display element (glass substrate) was obtained.
"Fabrication of liquid crystal display element (plastic substrate)"
The liquid crystal aligning agents obtained by the methods of the Examples and Comparative Examples were filtered under pressure using a membrane filter with a pore diameter of 1 μm. The obtained solution was applied with a bar coater onto the ITO surface of a 150 x 150 mm PET substrate with ITO electrodes (length: 150 mm, width: 150 mm, thickness: 0.1 mm), which had been washed with pure water, and thermal circulation was performed. A heat treatment was performed at 120° C. for 2 minutes in a mold oven to obtain an ITO substrate with a liquid crystal alignment film having a film thickness of 100 nm. Two ITO substrates with the liquid crystal alignment film were prepared, and a 10 μm spacer was applied to the surface of the liquid crystal alignment film of one of the substrates. Thereafter, the liquid crystal compositions (A) to (C) are dropped by the ODF (One Drop Filling) method onto the liquid crystal alignment film surface of the other substrate coated with the spacer, and then the liquid crystal alignment film surface of the other substrate is coated with the liquid crystal alignment film surface. They were bonded so that they faced each other, and an unprocessed liquid crystal display element was obtained. Note that when dropping and bonding the liquid crystal composition using the ODF method, a glass substrate was used as a support substrate for the PET substrate with an ITO electrode. Thereafter, the supporting substrate was removed before irradiation with ultraviolet light.

The liquid crystal display element before this treatment was irradiated with ultraviolet rays in the same manner as in the above-mentioned "Preparation 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 performed by measuring the haze (cloudiness) of the liquid crystal display element (glass substrate and plastic substrate) in a state where no voltage is applied (0 V) and a state where a voltage is applied (AC drive: 10 V to 60 V). At that time, Haze was measured using a haze meter (HZ-V3, manufactured by Suga Test Instruments Co., Ltd.) in accordance with JIS K 7136. In this evaluation, the lower the Haze in a state where no voltage is applied, the better the transparency, and the higher the Haze in the state where a voltage is applied, the better the scattering properties are.

In addition, as a stability test of the liquid crystal display element under a high temperature and high humidity environment, measurements were also performed after storage for 24 hours in a constant temperature and humidity chamber at a temperature of 80° C. and a humidity of 90% RH. Specifically, the smaller the change in haze after storage in a constant temperature and humidity chamber compared to the initial haze, the better this evaluation was.

Furthermore, as a stability test against light irradiation of the liquid crystal display element, observations were also made after irradiation with ultraviolet rays of 5 J/cm ² in terms of 365 nm using a tabletop UV curing device (HCT3B28HEX-1) (manufactured by Senrite). went. Specifically, the smaller the change in haze after ultraviolet irradiation compared to the initial haze, the better this evaluation was.

The Haze measurement results at the initial stage, after storage in a constant temperature and humidity chamber (constant temperature and humidity), and after UV irradiation (ultraviolet light) are summarized in Tables 5 to 7.
"Evaluation of adhesion between liquid crystal layer and liquid crystal alignment film (liquid crystal alignment film and electrode)"
This evaluation was performed by storing the liquid crystal display element (glass substrate and plastic substrate) in a constant temperature and humidity chamber at a temperature of 80°C and humidity of 90% RH for 24 hours, and checking for peeling of the liquid crystal display element and the presence of air bubbles. (as a stability test of liquid crystal display elements under high temperature and high humidity environments). Specifically, devices with no peeling (separation of the liquid crystal layer and liquid crystal alignment film, or separation of the liquid crystal alignment film and electrodes), and devices with no air bubbles generated within the device were subjected to this evaluation. It was judged to be excellent in terms of quality (shown as good in the table). At that time, in Examples 14 to 16, Example 20, and Example 21, in addition to the standard test, as an emphasis test, the samples were stored in a constant temperature and humidity chamber at a temperature of 80°C and a humidity of 90% RH for 96 hours. I also checked later. Note that the evaluation method is the same as described above.

In addition, confirmation was also conducted after irradiating the liquid crystal display element with ultraviolet rays of 5 J/cm ² in terms of 365 nm using a tabletop UV curing device (HCT3B28HEX-1) (manufactured by Senlight) (the light of the liquid crystal display element (as a stability test against irradiation). Specifically, those in which no peeling of the element occurred and those in which no air bubbles were generated within the element were considered to be excellent in this evaluation (denoted as good in the table).

The adhesion results (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 chamber (constant temperature and humidity), and after irradiation with ultraviolet light (ultraviolet light) are shown in Tables 8 to 9. They are summarized in 10.
<Example 14 to Example 26 and Comparative Example 5 to Comparative Example 8>
Production of a liquid crystal display element by the method described above using any of the liquid crystal aligning agents (1) to (16) obtained by the methods of the Examples and Comparative Examples and the liquid crystal compositions (A) to (C). , optical properties (scattering properties and transparency), and adhesion between the liquid crystal layer and the liquid crystal alignment film (liquid crystal alignment film and electrode) were evaluated.
At that time, in Examples 14 to 18, Example 26, Comparative Example 5, Comparative Example 6, and Comparative Example 8, liquid crystal display elements were manufactured using glass substrates and each evaluation was performed. In No. 25 and Comparative Example 7, a plastic substrate was used.

Furthermore, in Comparative Example 8, the liquid crystals were not vertically aligned, so each evaluation could not 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 standard test, as an emphasis test, a temperature of 80 An evaluation was also made when the sample was stored for 96 hours in a constant temperature and humidity chamber at 90% RH (other conditions were the same as above).

*4: Measurement could not be performed because the liquid crystal was not vertically aligned.

*4: Measurement could not be performed because the liquid crystal was not vertically aligned.
*5: A very small amount of air bubbles was observed within the element.
*6: A small amount of bubbles were observed within the element (more than *5).
*7: Bubbles were observed within the element (more than *6).
*8: Many bubbles were observed within the element (more than *7).

As mentioned above, the liquid crystal display element of the example using the liquid crystal aligning agent containing the specific compound and the polymer having the specific structure (1) was stored in a constant temperature and humidity bath compared to the comparative example that did not use the same. Changes in haze after UV irradiation and after UV irradiation became smaller. Furthermore, in the examples, no peeling of the liquid crystal display element or generation of bubbles was observed even after storage in a constant temperature and humidity chamber and after irradiation with ultraviolet rays. These results were similar even when a plastic substrate was used as the substrate of the liquid crystal display element. Specifically, a comparison is made between Example 14 and Comparative Example 5, a comparison between Example 18 and Comparative Example 6, and a comparison between Example 20 and Comparative Example 7.
In addition, when a polyimide polymer is used as a polymer, the terminal of the polymer has a structure of carboxylic acid or dicarboxylic acid, that is, during the polymerization reaction of the diamine component and the tetracarboxylic acid component, the tetracarboxylic acid component If the total number of moles is larger than the number of moles of the diamine component, the polymer terminal has an amino group structure (during the polymer reaction, the total number of moles of the tetracarboxylic acid component is smaller than the number of moles of the diamine component). The generation of air bubbles inside the liquid crystal display element in the emphasis test was suppressed compared to the previous one. Specifically, this is a comparison between Example 14 and Example 15 under the same conditions.
Furthermore, in the specific structure (1), when the specific diamine (1) having the structure of the formula [2-1] is used, the initial value is lower than that of the diamine having the structure of the formula [2-2]. Changes in haze after storage in a constant temperature and humidity chamber and after irradiation with ultraviolet rays became smaller. Specifically, this is a comparison between Example 15 and Example 26 under the same conditions.
Further, when the specific diamine (2) having the specific structure (2) was used as the polymer, the generation of bubbles in the liquid crystal display element in the emphasis test was suppressed. Specifically, this is a comparison between Example 15 and Example 16 under the same conditions.

In addition, when a specific crosslinking compound was introduced into the liquid crystal aligning agent, the generation of bubbles within the liquid crystal display element in the emphasis test was suppressed. Specifically, this is a comparison between Example 20 and Example 21 under the same conditions.

When a liquid crystal composition containing a specific liquid crystal additive compound was used, the transparency of the liquid crystal display element was higher (haze was smaller when no voltage was applied), and the driving voltage was lower than when the liquid crystal composition was not used. Specifically, this is a comparison between Example 21 and Example 22 under the same conditions.

By using a liquid crystal alignment film obtained from a liquid crystal alignment treatment agent containing a compound with a specific structure and a polymer with a specific structure, it can be used in harsh environments where it is exposed to high temperature, high humidity, and light irradiation for long periods of time. Also, a liquid crystal display element can be obtained in which peeling of the element, generation of bubbles, and deterioration of optical properties can be suppressed.

Further, the liquid crystal display element of the present invention can be suitably used as a reverse type element that is in a transparent state when no voltage is applied and becomes a scattering state when a voltage is applied. This element can be used in liquid crystal displays for display purposes, as well as in dimming windows and optical shutter elements that control the blocking and transmission of light.The substrate of this reverse type element is made of plastic. A substrate can be used.

The entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2019-034307 filed on February 27, 2019 are cited here and incorporated as disclosure of the specification of the present invention. It is.

Claims (18)

a liquid crystal layer that is cured by applying at least one of active energy rays and heat to a liquid crystal composition containing a liquid crystal and a polymerizable compound disposed between a pair of substrates provided with electrodes; A transmission-scattering reverse type liquid crystal display element comprising a liquid crystal alignment film on one side, and further having a transparent state when no voltage is applied and a scattering state when a voltage is applied,
A liquid crystal display element, wherein the liquid crystal alignment film is obtained from a liquid crystal alignment treatment agent containing the following components (A) and (B).
Component (A): A compound having a group represented by the following formula [1].
Component (B): A polymer having at least one structure selected from the following formulas [2-1] and [2-2].

* represents a binding site with another structure.

X ¹ is a single bond, -(CH ₂ ) _a - (a is an integer from 1 to 15), -O-, -CH ₂ O-, -CONH-, -NHCO-, -CON(CH ₃ ) -, -N(CH ₃ )CO-, -COO- and -OCO-. X ² represents a single bond or -(CH ₂ ) _b - (b is an integer from 1 to 15). X ³ represents at least one selected from a single bond, -(CH ₂ ) _c - (c is an integer from 1 to 15), -O-, -CH ₂ O-, -COO- and -OCO- show. X ⁴ represents at least one divalent cyclic group selected from a benzene ring, a cyclohexane ring, and a heterocycle, or a divalent organic group having 17 to 51 carbon atoms and having a steroid skeleton; The hydrogen atom is substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom. You can leave it there. X ⁵ represents at least one cyclic group selected from a benzene ring, a cyclohexane ring, and a heterocycle, and any hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms, or an alkyl group having 1 to 3 carbon atoms. may be substituted with an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom. Xn represents an integer from 0 to 4. X ⁶ is an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxyl group having 1 to 18 carbon atoms, and a fluorine-containing group having 1 to 18 carbon atoms. At least one type selected from alkoxyl groups is shown.

X ⁷ is a single bond, -O-, -CH ₂ O-, -CONH-, -NHCO-, -CON(CH ₃ )-, -N(CH ₃ )CO-, -COO- and -OCO- At least one selected type is shown. X ⁸ represents an alkyl group having 8 to 22 carbon atoms or a fluorine-containing alkyl group having 6 to 18 carbon atoms. The liquid crystal display element according to claim 1, wherein the compound has the following formula [1a].

T ¹ represents at least one structure selected from the following formulas [1-a] to [1-h]. T ² represents a single bond or an organic group having 1 to 18 carbon atoms. T ³ represents the structure of the above formula [1].

T ^A represents an alkyl group having 1 to 3 carbon atoms. The liquid crystal display element according to claim 1 or 2, 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. According to any one of claims 1 to 3, wherein the liquid crystal aligning agent further contains a polymer having at least one structure selected from the following formulas [3-a] to formula [3-i]. The liquid crystal display element described above.

^YA represents a hydrogen atom or a benzene ring. Any one of claims 1 to 4, wherein the polymer is at least one selected from acrylic polymer, methacrylic polymer, novolac resin, polyhydroxystyrene, polyimide precursor, polyimide, polyamide, polyester, cellulose, and polysiloxane. The liquid crystal display element according to item 1. 6. The liquid crystal display element according to claim 5, wherein the polymer is a polyimide precursor obtained by reacting a diamine component and a tetracarboxylic acid component, or a polyimide obtained by imidizing the polyimide precursor. The liquid crystal display element according to claim 6, wherein the diamine component contains a diamine having at least one type of structure selected from the formula [2-1] and the formula [2-2]. The liquid crystal display element according to claim 7, wherein the diamine has the following formula [2a].

X represents at least one structure selected from the above formula [2-1] and formula [2-2]. Xm represents an integer of 1 to 4. The liquid crystal display element according to any one of claims 6 to 8, wherein the diamine component includes a diamine having a structure represented by the following formula [3].

Y ¹ is a single bond, -O-, -NH-, -N(CH ₃ )-, -CH ₂ O-, -CONH-, -NHCO-, -CON(CH ₃ )-, -N(CH ₃ ) represents at least one selected from CO-, -COO- and -OCO-. Y ² 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 heterocycle; The hydrogen atom is substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom. It's okay. Y ³ is a single bond, -O-, -NH-, -N(CH ₃ )-, -CH ₂ O-, -CONH-, -NHCO-, -CON(CH ₃ )-, -N(CH ₃ ) represents at least one selected from CO-, -COO- and -OCO-. Y ⁴ represents at least one structure selected from the above formulas [3-a] to [3-i]. Yn represents an integer of 1 to 4. The liquid crystal display element according to claim 9, wherein the diamine has the following formula [3a].

Y represents the structure of the above formula [3]. Ym represents an integer from 1 to 4. The liquid crystal display element according to any one of claims 6 to 10, wherein the tetracarboxylic acid component contains a tetracarboxylic dianhydride represented by the following formula [4].

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

Z ^A to Z ^D each represent a hydrogen atom, a methyl group, a chlorine atom, or a benzene ring. Z ^E and Z ^F each represent a hydrogen atom or a methyl group. In the reaction between the diamine component and the tetracarboxylic acid component, the total number of moles of the tetracarboxylic acid component is 1.05 to 1.20 when the total number of moles of the diamine component is 1.0. The liquid crystal display element according to any one of Item 11. The liquid crystal display element according to any one of claims 1 to 12, wherein the liquid crystal composition contains a compound represented by the following formula [5a].

S ¹ represents at least one structure selected from the following formulas [5-a] to [5-j]. S ² is a single bond, -O-, -NH-, -N(CH ₃ )-, -CH ₂ O-, -CONH-, -NHCO-, -CON(CH ₃ )-, -N(CH ₃ ) represents at least one selected from CO-, -COO- and -OCO-. S ³ represents a single bond or -(CH ₂ ) _a - (a is an integer from 1 to 15). S ⁴ represents at least one selected from a single bond, -O-, -OCH ₂ -, -COO-, and -OCO-. S ⁵ represents a divalent cyclic group selected from a benzene ring, a cyclohexane ring, and a heterocycle, or a divalent organic group having 17 to 51 carbon atoms and having a steroid skeleton, and any hydrogen atom on the cyclic group is , may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom. . S ⁶ represents at least one selected from a single bond, -O-, -CH ₂ -, -OCH ₂ -, -CH ₂ O-, -COO- and -OCO-. S ⁷ represents a cyclic group selected from a benzene ring, a cyclohexane ring, and a heterocycle, and any hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, It may be substituted with a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom. S ⁸ is an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, and a fluorine-containing group having 1 to 18 carbon atoms. At least one type selected from alkoxy groups is shown. Sm represents an integer from 0 to 4.

S ^A represents a hydrogen atom or a benzene ring. 14. The liquid crystal display element according to claim 13, wherein the compound of formula [5a] is at least one selected from the following formulas [5a-1] to [5a-11].

S ^a each represents -O- or -COO-. Each S ^b represents an alkyl group having 1 to 12 carbon atoms. p1 each represents an integer from 1 to 10. p2 each represents an integer of 1 or 2.

S ^c each represents a single bond, -COO- or -OCO-. S ^d each represents an alkyl group or an alkoxy group having 1 to 12 carbon atoms. p3 each represents an integer from 1 to 10. p4 each represents an integer of 1 or 2.

S ^e each represents -O- or -COO-. S ^f each represents a divalent organic group having a steroid skeleton and having 17 to 51 carbon atoms. S ^g each represents an alkyl group having 1 to 12 carbon atoms or an alkenyl group having 2 to 18 carbon atoms. p5 each represents an integer from 1 to 10. Claims 1 to 3, wherein the liquid crystal aligning agent further contains a crosslinkable compound having at least one selected from an epoxy group, an isocyanate group, an oxetane group, a cyclocarbonate group, a hydroxy group, a hydroxyalkyl group, and a lower alkoxyalkyl group. The liquid crystal display element according to claim 14. The liquid crystal display element according to any one of claims 1 to 15, wherein the substrate of the liquid crystal display element is a glass substrate or a plastic substrate. A liquid crystal alignment film used in the liquid crystal display element according to any one of claims 1 to 16, which is formed from a liquid crystal alignment treatment agent containing the component (A) and the component (B). A liquid crystal aligning agent for forming a liquid crystal aligning film according to claim 17, comprising the (A) component and the (B) component.