WO2020138109A1 - Liquid crystal alignment treatment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Abstract

Provided are: a liquid crystal alignment treatment agent that can be used to produce a liquid crystal alignment film that has outstanding preservation stability, provides high adhesiveness (adhesion) between substrates of a liquid crystal display element, and can suppress air bubbles generating within the liquid crystal display element as well as detachment of the element even in an environment exposed to high temperature and high humidity for a long period of time; a liquid crystal alignment film obtained by using said agent; and a liquid crystal display element. The liquid crystal alignment treatment agent contains a compound including a group represented by a formula [1]. (* represents the site of bonding with another structure.)

Description

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

The present invention relates to a liquid crystal alignment treatment agent used for manufacturing a liquid crystal display element, a liquid crystal alignment film obtained from the liquid crystal alignment treatment agent, and a liquid crystal display element using the liquid crystal alignment film.

A film made of an organic material such as a polymer material is widely used as an interlayer insulating film, a protective film, etc. in electronic devices, because of its ease of formation and insulating performance. Among them, in a liquid crystal display element well known as a display device, an organic film made of polyimide is used as a liquid crystal alignment film.

The liquid crystal alignment film is used to control the alignment state of the liquid crystal. However, as the resolution of liquid crystal display elements increases, it is required to reduce the contrast of the liquid crystal display elements and suppress display defects due to long-term use.

On the other hand, in a liquid crystal alignment film using polyimide, a liquid crystal alignment treatment using a liquid crystal alignment treatment agent containing an alkoxysilane compound is used as a method of improving the liquid crystal alignment property and making it difficult for a display defect to occur in the peripheral portion of the liquid crystal display screen. Membranes have been proposed (see Patent Documents 1 and 2).

Japanese Patent Laid-Open No. 61-171762 Japanese Patent Laid-Open No. 11-119226

In recent years, liquid crystal display devices have been used for mobile applications such as smartphones and mobile phones. In these applications, in order to secure a display surface as wide as possible, it is necessary to make the width of the sealant used for bonding the substrates of the liquid crystal display element narrower than in the conventional case. Further, for the above reason, it is also required that the drawing position of the sealant is at a position in contact with the end of the liquid crystal alignment film, which has weak adhesion to the sealant, or at the upper part of the liquid crystal alignment film. Therefore, in recent years, the adhesion between the substrates of the liquid crystal display element has become weaker than in the past. Furthermore, in such a case, when used under high temperature and high humidity conditions, water easily mixes in between the sealant and the liquid crystal alignment film, resulting in display unevenness near the frame of the liquid crystal display element and bubbles in the element. Occurs, and the element peels off.

For this problem, there is a method of adding an alkoxysilane compound to the liquid crystal alignment treatment agent as a method of improving the adhesion between the liquid crystal alignment film and the sealant. However, when the alkoxysilane compound is added to the liquid crystal alignment treatment agent, the adhesiveness between the sealant and the liquid crystal alignment film can be increased, but the condensation reaction of the alkoxy group in the alkoxy compound during storage of the liquid crystal alignment treatment agent Occurs, and there is a problem that the storage stability of the liquid crystal alignment treatment agent deteriorates, such as an increase in the viscosity of the liquid crystal alignment treatment agent and the generation of a gelled product.

From the above points, the present invention is excellent in storage stability of the liquid crystal alignment treatment agent, has high adhesiveness (also referred to as adhesiveness) between the substrates of the liquid crystal display element, and is further exposed to high temperature and high humidity for a long time. It is an object of the present invention to provide a liquid crystal alignment film capable of suppressing the generation of bubbles in the liquid crystal display element and the peeling of the element even under such an environment. In addition, another object is to provide a liquid crystal display device having the above liquid crystal alignment film and a liquid crystal alignment treatment agent capable of producing the above liquid crystal alignment film.

As a result of earnest research to achieve the above-mentioned object, the present inventor has completed the present invention having the following points.
That is, it is a liquid crystal alignment treatment agent containing a compound having a group represented by the following formula [1] (also referred to as a specific compound).

(* represents a binding site with another structure.)

The liquid crystal alignment treatment agent of the present invention is excellent in storage stability, has high adhesiveness between substrates of a liquid crystal display element, and further, even in an environment exposed to high temperature and high humidity for a long time, bubbles in the liquid crystal display element It is possible to provide a liquid crystal alignment film capable of suppressing generation and peeling of elements. In addition, a liquid crystal display device having the above liquid crystal alignment film and a liquid crystal alignment treatment agent capable of producing the above liquid crystal alignment film can be provided. Therefore, the liquid crystal display element of the present invention is used for a liquid crystal display element such as a smartphone or a mobile phone.

The mechanism by which the liquid crystal display device having the above-mentioned excellent characteristics is obtained by the present invention is not necessarily clear, but it is presumed as follows.
Since the specific compound contained in the liquid crystal alignment treatment agent has a disulfide bond (SS) and a thioketone (C=S) group, the adhesion between the liquid crystal alignment film and the metal electrode becomes high. In addition, the amino group (N) in the characteristic compound exhibits weak basicity, so that the curability of the sealant can be promoted. As a result, after the liquid crystal alignment film is formed, the adhesion between the liquid crystal alignment film and the metal electrode, and the liquid crystal alignment film and the sealant becomes high, and even in an environment where the liquid crystal alignment film is exposed to high temperature and high humidity for a long time, It is considered that the liquid crystal display device can suppress the generation of bubbles and the peeling of the device.

<Specific compound>
The specific compound is a compound having a group represented by the above formula [1]. Specifically, a compound represented by the following formula [1a] can be mentioned.

X ¹ is selected from the group consisting of the following formulas [1-a] to [1-k].

^{(T A} represents an alkyl group having 1 to 3 carbon atoms.)
Among them, the formula [1-b], the formula [1-c] or the formula [1-d] is preferable.
X ² represents a single bond or an organic group having 1 to 18 carbon atoms. Of these, a single bond or an organic group having 1 to 6 carbon atoms is preferable.
X ³ represents a group represented by the above formula [1].

Specific preferred examples of the specific compound include compounds represented by the following formula [1-1a], and it is preferable to use these.

From the viewpoint of adhesion between the liquid crystal alignment film of the liquid crystal display element and the metal electrode, the specific compound is used in an amount of 0.1 to 30 parts by mass based on 100 parts by mass of all the polymers contained in the liquid crystal alignment treatment agent. The amount is preferably 0.5 part by mass, more preferably 0.5 to 20 parts by mass, and most preferably 1 to 15 parts by mass. In addition, the specific compound may be used alone or in combination of two or more depending on each characteristic.

<Polymer>
The polymer contained in the liquid crystal alignment treatment agent is preferably a polymer having a functional group capable of reacting with the specific compound. The functional group capable of reacting is a concept that includes a functional group capable of forming a covalent bond at room temperature as well as a functional group capable of potentially forming a covalent bond. Examples of such a functional group include heating and/or electromagnetic waves. A functional group capable of forming a covalent bond with a specific compound by changing a part of the structure by irradiation with. Specific examples of the functional group capable of reacting include a carboxyl group, an amino group, a (meth)acrylic group, an acid anhydride group, a phenol group, a hydroxyl group, a silanol group, an imide group, an ester group, an amide group, and a urea group. ..

The polymer having a functional group capable of reacting with the specific compound is at least selected from the group consisting of acrylic polymer, methacrylic polymer, novolac resin, polyhydroxystyrene, polyimide precursor, polyimide, polyamide, polyester, cellulose, and polysiloxane. One kind is preferable. More preferably, it is a polyimide precursor or polyimide.
When a polyimide precursor or a polyimide (collectively referred to as a polyimide-based polymer) is used as the polymer, they are a polyimide precursor obtained by reacting a diamine component and a tetracarboxylic acid component or the polyimide. A polyimide obtained by imidizing a precursor is preferable.

The polyimide precursor preferably has a structure represented by the following formula [A].

In 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 independently 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 may be a diamine having two primary or secondary amino groups in the molecule. Examples of the tetracarboxylic acid component include a tetracarboxylic acid compound, a tetracarboxylic acid dianhydride, a tetracarboxylic acid dihalide compound, a tetracarboxylic acid dialkyl ester compound, and a tetracarboxylic acid dialkyl ester dihalide compound.

A polyimide-based polymer can be obtained relatively easily by using a tetracarboxylic acid dianhydride of the following formula [B] and a diamine of the following formula [C] as a raw material, so that the following formula [D] A polyamic acid having a structural formula of a repeating unit or a polyimide obtained by imidizing the polyamic acid is preferable.

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

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

Further, in a conventional synthetic procedures, the polymer of the formula [D] obtained by the above formula [A] alkyl group of A ¹ and A ² having 1 to 8 carbon atoms in, and in the formula [A] It is also possible to introduce an alkyl group having 1 to 5 carbon atoms or an acetyl group of A ³ and A ⁴ .
The diamine component for producing the polyimide polymer is not particularly limited. Specifically, the diamine compounds of the formulas [3a-1] to [3a-5] described on pages 34 to 38 of WO 2016/076412 and pages 39 to 42 of the publication. Other examples include diamine compounds and the diamine compounds of the formulas [DA1] to [DA15] described on pages 42 to 44 of the publication. These diamine components may be used either individually or in combination of two or more, depending on the characteristics.

The tetracarboxylic acid component for producing the polyimide polymer is not particularly limited. Specifically, the tetracarboxylic dianhydride of the formula [4] described on pages 44 to 45 of International Publication WO2016/076412 and the other tetracarboxylic acid components described on pages 45 to 46 are Can be mentioned. These tetracarboxylic acid components may be used either individually or in combination of two or more, depending on the characteristics.

The method for synthesizing the polyimide polymer is not particularly limited. Usually, it is obtained by reacting a diamine component and a tetracarboxylic acid component. Specific examples thereof include the methods described on pages 46 to 50 of International Publication WO2016/076412.
The reaction between the diamine component and the tetracarboxylic acid component is usually performed in a solvent containing the diamine component and the tetracarboxylic acid component. The solvent used at that time is not particularly limited as long as it can dissolve the generated polyimide precursor.

Specifically, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide or 1,3-dimethyl-imidazolidinium Non is included. When the polyimide precursor has high solvent solubility, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone or a solvent represented by the following formula [D1] to [D3] is used. it 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.)

Also, these may be used alone or as a mixture. Further, even a solvent that does not dissolve the polyimide precursor may be used by mixing with the above-mentioned solvent as long as the generated polyimide precursor does not precipitate. Further, since water in the organic solvent inhibits the polymerization reaction and causes hydrolysis of the generated polyimide precursor, it is preferable to use dehydrated and dried organic solvent.

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 less than 1.0, that is, when the total number of moles of the tetracarboxylic acid component is less than the number of moles of the diamine component, the polymer has an amino group structure at the terminal. When it is greater than 0, that is, when the total number of moles of the tetracarboxylic acid component is greater than the number of moles of the diamine component, the polymer end has a carboxylic acid anhydride or dicarboxylic acid structure. In the present invention, the effect of the specific compound, that is, the effect of enhancing the adhesiveness between the liquid crystal alignment film of the liquid crystal display element and the metal electrode becomes higher, so that the total number of moles of the tetracarboxylic acid component is more than 1.0. It is preferable that the total number of moles of the tetracarboxylic acid component is larger than that of the diamine component. Specifically, when the total number of moles of the diamine component is 1.0, the total number of moles of the tetracarboxylic acid component is preferably 1.05 to 1.20.

Polyimide is obtained by ring-closing a polyimide precursor. The polyimide does not necessarily have a ring closure rate (also referred to as an imidization rate) of an amic acid group of 100%, and can be arbitrarily prepared according to the application or purpose. Among them, 30 to 80% is preferable from the viewpoint of the solubility of the polyimide polymer in the solvent. More preferably, it is 40 to 70%.
The molecular weight of the polyimide-based polymer is 5 in terms of weight average molecular weight measured by GPC (Gel Permeation Chromatography) method in consideration of the strength of the liquid crystal alignment film obtained therefrom, workability in forming the liquid crystal alignment film, and coating property. It is preferably from 1,000 to 1,000,000, and more preferably from 10,000 to 150,000.

<Liquid crystal orientation treatment agent>
The liquid crystal alignment treatment agent is a solution for forming a liquid crystal alignment film, and is a solution containing a specific compound, a polymer and a solvent. In that case, two or more types can be used for each of a specific compound and a polymer.
The content of the solvent in the liquid crystal alignment treatment agent can be appropriately selected from the viewpoint of applying the liquid crystal alignment treatment agent and obtaining a target film thickness. Among them, the content of the solvent in the liquid crystal alignment treatment agent is preferably 50 to 99.9 mass% from the viewpoint of forming a uniform liquid crystal alignment film by coating. Among them, 60 to 99 mass% is preferable. More preferably, it is 65 to 99% by mass.

The solvent used for the liquid crystal alignment treatment agent is not particularly limited as long as it is a solvent that dissolves the specific compound and the polymer. Among them, when the polymer is a polyimide precursor, polyimide, polyamide or polyester, or when the solubility of the acrylic polymer, methacrylic polymer, novolac resin, polyhydroxystyrene, cellulose or polysiloxane in the solvent is low, It is preferable to use a solvent (also referred to as a solvent A).

For example, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, 1,3-dimethyl-imidazolidinone, methyl ethyl ketone , Cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone and the like. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ-butyrolactone is preferable. Moreover, these may be used individually or may be mixed and used.

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

Specific examples of the solvent Bs include the solvent Bs described on pages 58 to 60 of International Publication WO2014/171493. 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] To Formula [D3] are preferred.

Further, when these solvent Bs are used, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ-butyrolactone of the above-mentioned solvent A is used in combination for the purpose of improving the coating property of the liquid crystal alignment treatment agent. It is preferable to use.
Since these solvents B can enhance the coating property and surface smoothness of the liquid crystal alignment film when applying the liquid crystal alignment treatment agent, when a polyimide precursor, polyimide, polyamide or polyester is used as the polymer, It is preferable to use it in combination with the above solvents A. At that time, the amount of the solvent B is preferably 1 to 99% by mass of the whole solvent contained in the liquid crystal alignment treatment agent. Among them, 10 to 99 mass% is preferable. More preferably, it is 20 to 95% by mass.

The liquid crystal alignment treatment agent includes a compound having an epoxy group, an isocyanate group, an oxetane group, a cyclocarbonate group, a hydroxy group, a hydroxyalkyl group or a lower alkoxyalkyl group (collectively, a crosslinker in order to enhance the film strength of the liquid crystal alignment film It is also preferable to introduce a compound). In that case, it is necessary to have two or more groups in the compound.
That is, the liquid crystal alignment treatment agent is a group selected from an epoxy group, an isocyanate group, an oxetane group, a cyclocarbonate group, a hydroxyl group, a hydroxyalkyl group, an alkoxyalkyl group having 1 to 3 carbon atoms, or a polymerizable unsaturated bond group. It is preferable to include at least one crosslinkable compound composed of a compound having two or more.

Specific examples of the crosslinkable compound having an epoxy group or an isocyanate group include the crosslinkable compounds having an epoxy group or an isocyanate group described on pages 63 to 64 of WO 2014/171493.
Specific examples of the crosslinkable compound having an oxetane group include crosslinkable compounds of the formulas [4a] to [4k] described on pages 58 to 59 of International Publication WO2011/132751.

Specific examples of the crosslinkable compound having a cyclocarbonate group include crosslinkable compounds of the formulas [5-1] to [5-42] described on pages 76 to 82 of WO 2012/014898.
Specific examples of the crosslinkable compound 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 WO2014/171349, and WO2011/132751. And the crosslinkable compounds of the formulas [6-1] to [6-48] listed on pages 62 to 66.

The content of the crosslinkable compound in the liquid crystal alignment treatment agent is preferably 0.1 to 100 parts by mass with respect to 100 parts by mass of all polymer components contained in the liquid crystal alignment treatment agent. In order to allow the crosslinking reaction to proceed and to produce the desired effect, 0.1 to 50 parts by mass is more preferable, and 1 to 30 parts by mass is most preferable, relative to 100 parts by mass of all polymer components. ..
As the liquid crystal alignment treatment agent, a compound that improves the film thickness uniformity and the surface smoothness of the liquid crystal alignment film when the liquid crystal alignment treatment agent is applied can be used. Further, a compound or the like that improves the adhesiveness between the liquid crystal alignment film and the electrode substrate can be used.

Compounds that improve the film thickness uniformity and surface smoothness of the liquid crystal alignment film include fluorine-based surfactants, silicone-based surfactants, and nonion-based surfactants. Specific examples thereof include the surfactants described on page 67 of International Publication WO2014/171493. Further, the use ratio thereof is preferably 0.01 to 2 parts by mass with respect to 100 parts by mass of all polymer components contained in the liquid crystal alignment treatment agent. More preferably, it is 0.01 to 1 part by mass.

Specific examples of the compound that improves the adhesiveness between the liquid crystal alignment film and the electrode substrate include the compounds described on pages 67 to 69 of International Publication WO2014/171493. Further, the use ratio thereof is preferably 0.1 to 30 parts by mass with respect to 100 parts by mass of all polymer components contained in the liquid crystal alignment treatment agent. More preferably, it is 1 to 20 parts by mass.
In addition to the compounds other than the above, a liquid crystal alignment treatment agent may be added with 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 alignment film.

<Liquid crystal alignment film/liquid crystal display element>
The liquid crystal alignment treatment agent can be used as a liquid crystal alignment film by applying alignment treatment by rubbing treatment or light irradiation after coating and baking on the substrate. Further, in the case of vertical alignment applications, it can be used as a liquid crystal alignment film without alignment treatment.

The substrate used in this case is not particularly limited as long as it is a highly transparent substrate, and in addition to glass substrates, acrylic substrates, polycarbonate substrates, plastic substrates such as PET (polyethylene terephthalate) substrates, and further films thereof. Can be used. From the viewpoint of simplifying the process, a substrate on which an ITO electrode for driving a liquid crystal, a metal electrode such as an IZO (Indium Zinc Oxide) electrode and an IGZO (Indium Gallium Zinc Oxide) electrode, and an organic conductive film are formed. Is preferably used. Further, in the case of a reflective liquid crystal display element, if only one substrate is used, a substrate such as a silicon wafer or a metal such as aluminum or a substrate on which a dielectric multilayer film is formed can be used.

The method for applying the liquid crystal alignment treatment agent is not particularly limited, but industrially, a method such as screen printing, offset printing, flexographic printing or an inkjet method is generally used. Other coating methods include a dip method, a roll coater method, a slit coater method, a spinner method or a spray method, and these may be used depending on the purpose.
After applying the liquid crystal alignment treatment agent on the substrate, it is preferably heated at 30 to 300° C., depending on the solvent used for the liquid crystal alignment treatment agent, by a heating means such as a hot plate, a heat circulation type oven or an IR (infrared) type oven. Can be used as a liquid crystal alignment film by evaporating the solvent at a temperature of 30 to 250° C.

If the thickness of the liquid crystal alignment film after firing is too thick, it is disadvantageous in terms of power consumption of the liquid crystal display device, and if it is too thin, the reliability of the liquid crystal display device may be deteriorated. Is 10 to 200 nm.
When the liquid crystal is horizontally or tilted, the liquid crystal alignment film after firing is treated by rubbing or irradiation with polarized ultraviolet light.
The liquid crystal used for the liquid crystal display element is not particularly limited, but for example, nematic liquid crystal, smectic liquid crystal or cholesteric liquid crystal can be used. At that time, a liquid crystal having a positive or negative dielectric anisotropy can be selected according to the method of the liquid crystal display element. Alternatively, a dichroic dye may be dissolved in the liquid crystal to form a guest-host type liquid crystal display device.

The method of injecting the liquid crystal is not particularly limited, but for example, the following method may be mentioned. That is, a pair of substrates on which a liquid crystal alignment film is formed is prepared, and a sealant is applied to all four of the substrates on one side except for a part thereof, and then the liquid crystal alignment film surface is placed inside and the other side is applied. An empty cell in which the above substrates are bonded together is produced. Then, a method of injecting liquid crystal under reduced pressure from a place where the sealant is not applied to obtain a liquid crystal injection cell can be mentioned. Furthermore, prepare a pair of substrates on which a liquid crystal alignment film is formed, drop the liquid crystal on one substrate by ODF (One Drop Filling) method or inkjet method, and then bond the other substrate. Another method is to obtain a liquid crystal injection cell.

The method of controlling the gap of the liquid crystal display device is not particularly limited, for example, a method of introducing a spacer of a desired size in the liquid crystal, a method of coating on a substrate having a column spacer of the desired size, the purpose A method using a liquid crystal containing a column spacer having a size of
The size of the gap of the liquid crystal display element is preferably 1 to 100 μm, more preferably 1 to 50 μm, and particularly preferably 2 to 30 μm. If the gap is too small, the contrast of the liquid crystal display device will be lowered, and if it is too large, the driving voltage of the device will be high.

Hereinafter, the present invention will be described in more detail by way of examples, but the invention is not limited thereto. The abbreviations used below are as follows.
"Specific compound"

<Diamine component>

<Tetracarboxylic acid component>

"Crosslinkable compound"

"solvent"
NMP: N-methyl-2-pyrrolidone, NEP: N-ethyl-2-pyrrolidone BCS: ethylene glycol monobutyl ether PB: propylene glycol monobutyl ether

"Measurement of molecular weight of polyimide polymer"
The measurement was performed as follows using a room temperature gel permeation chromatography (GPC) device (GPC-101) (manufactured by Showa Denko KK) and a column (KD-803, KD-805) (manufactured by Shodex).
Column temperature: 50°C
Eluent: N,N'-dimethylformamide (additional lithium bromide hydrate (LiBr.H ₂ O) 30 mmol/L (liter), phosphoric acid/anhydrous crystal (o-phosphoric acid) 30 mmol) /L, tetrahydrofuran (THF) 10ml/L)
Flow rate: 1.0 ml/min Standard sample for preparing calibration curve: TSK standard polyethylene oxide (molecular weight; about 900,000, 150,000, 100,000 and 30,000) (manufactured by Tosoh Corporation) and polyethylene glycol (molecular weight; about) 12,000, 4,000 and 1,000) (manufactured by Polymer Laboratory).

"Measurement of imidization ratio of polyimide polymer"
20 mg of polyimide powder was put in an NMR (nuclear magnetic resonance) sample tube (NMR sampling tube standard, φ5 (Kusano Scientific Co., Ltd.)), and deuterated dimethyl sulfoxide (DMSO-d6, 0.05 mass% TMS (tetramethylsilane) was added. (Mixture) (0.53 ml) was added and ultrasonic waves were applied to completely dissolve. This solution was measured for proton NMR at 500 MHz with an NMR measuring device (JNW-ECA500) (manufactured by JEOL Datum). The imidization ratio is determined by using a proton derived from a structure that does not change before and after imidization as a reference proton, and the peak integrated value of this proton and the proton peak derived from the NH group of amic acid that appears near 9.5 ppm to 10.0 ppm. It was calculated by the following formula using the integrated value.
Imidization rate (%)=(1-α·x/y)×100
(X is a proton peak integrated value derived from NH group of amic acid, y is a peak integrated value of reference proton, α is a reference proton for one NH group proton of amic acid in the case of polyamic acid (imidization rate is 0%) Is the proportion of the number of.)

"Synthesis of polyimide polymers"
<Synthesis example 1>
C1 (2.50 g, 12.7 mmol) and B2 (2.65 g, 13.4 mmol) were mixed in NMP (15.5 g) and reacted at 25° C. for 8 hours to give a polyamide having a resin solid content concentration of 25% by mass. An acid solution (1) was obtained. The number average molecular weight (also referred to as Mn) of this polyamic acid was 28,200, and the weight average molecular weight (also referred to as Mw) was 85,300.

<Synthesis example 2>
C1 (2.50 g, 12.7 mmol) and B2 (2.40 g, 12.1 mmol) were mixed in NMP (14.7 g) and reacted at 25° C. for 8 hours to give a polyamide having a resin solid content concentration of 25% by mass. An acid solution (2) was obtained. The number average molecular weight (also referred to as Mn) of this polyamic acid was 30,600, and the weight average molecular weight (also referred to as Mw) was 89,500.

<Synthesis example 3>
C2 (2.04 g, 8.15 mmol) and B3 (5.55 g, 19.4 mmol) were mixed in NMP (20.0 g) and reacted at 60° C. for 4 hours, and then C1 (2.40 g, 12). .2 mmol) and NMP (10.0 g) were added and reacted at 40° C. for 6 hours to obtain a polyamic acid solution (3) having a resin solid content concentration of 25 mass %. The Mn of this polyamic acid was 26,900 and the Mw was 77,500.

<Synthesis example 4>
After adding NMP to the polyamic acid solution (3) (20.0 g) obtained in Synthesis Example 3 and diluting it to 6% by mass, acetic anhydride (2.50 g) and pyridine (1.90 g) were added as imidization catalysts. The mixture was reacted at 80°C for 3 hours. The deposit obtained by throwing in this reaction solution in methanol (500 ml) was separated by filtration. Methanol wash|cleaned this deposit, it dried under reduced pressure at 100 degreeC, and the polyimide powder (4) was obtained. The imidation ratio of this polyimide was 55%, Mn was 23,300, and Mw was 59,800.

<Synthesis example 5>
C2 (2.30 g, 9.19 mmol), B1 (1.56 g, 14.4 mmol) and B4 (3.67 g, 9.64 mmol) were mixed in NMP (20.5 g) and reacted at 80° C. for 4 hours. After that, C1 (2.70 g, 13.8 mmol) and NMP (10.2 g) were added and reacted at 40° C. for 6 hours to obtain a polyamic acid solution (5) having a resin solid content concentration of 25 mass %. .. The Mn of this polyamic acid was 21,800 and the Mw was 62,300.

<Synthesis example 6>
C2 (2.38 g, 9.51 mmol), B1 (1.47 g, 13.6 mmol) and B4 (3.44 g, 9.04 mmol) were mixed in NMP (20.2 g) and reacted at 80° C. for 4 hours. After that, C1 (2.80 g, 14.3 mmol) and NMP (10.1 g) were added and reacted at 40° C. for 6 hours to obtain a polyamic acid solution (6) having a resin solid content concentration of 25 mass %. .. The Mn of this polyamic acid was 23,100 and the Mw was 68,000.

<Synthesis example 7>
NMP was added to the polyamic acid solution (6) (20.0 g) obtained in Synthesis Example 6 to dilute it to 6% by mass, and then acetic anhydride (2.55 g) and pyridine (1.95 g) were added as imidization catalysts. The mixture was reacted at 80°C for 4 hours. The deposit obtained by throwing in this reaction solution in methanol (500 ml) was separated by filtration. Methanol wash|cleaned this deposit, it dried under reduced pressure at 100 degreeC, and the polyimide powder (7) was obtained. The imidation ratio of this polyimide was 62%, Mn was 21,400 and Mw was 49,700.

<Synthesis example 8>
NMP (20.2g) of C2 (2.47g, 9.87mmol), B1 (1.52g, 14.1mmol), B2 (0.93g, 4.69mmol) and B5 (2.31g, 4.69mmol). After mixing in and reacting at 80° C. for 6 hours, C1 (2.90 g, 14.8 mmol) and NMP (10.1 g) were added and reacted at 40° C. for 6 hours to give a resin solid content concentration of 25 mass. % Polyamic acid solution (8) was obtained. The Mn of this polyamic acid was 23,700 and the Mw was 69,100.

<Synthesis example 9>
C3 (5.20 g, 23.2 mmol), B1 (1.43 g, 13.2 mmol) and B4 (3.35 g, 8.80 mmol) were mixed in NMP (30.4 g) and reacted at 40° C. for 4 hours. Thus, a polyamic acid solution (9) having a resin solid content concentration of 25 mass% was obtained. The Mn of this polyamic acid was 26,800 and the Mw was 77,200.

<Synthesis example 10>
N3 (29.5 g) of C3 (5.40 g, 24.1 mmol), B1 (1.73 g, 16.0 mmol), B2 (0.45 g, 2.27 mmol) and B5 (2.26 g, 4.59 mmol). The mixture was mixed in and reacted at 40° C. for 6 hours to obtain a polyamic acid solution (10) having a resin solid content concentration of 25 mass %. The Mn of this polyamic acid was 23,100 and the Mw was 70,900.

<Synthesis example 11>
Under a nitrogen atmosphere, B2 (0.43 g, 2.17 mmol), B3 (2.50 g, 8.73 mmol), pyridine (2.15 g) and NMP (34.8 g) were added, and the mixture was stirred to dissolve, and C4( 3.20 g, 10.8 mmol) was added, and the mixture was reacted at 15° C. for 15 hours. Then, acryloyl chloride (0.05 g) was added, and the mixture was reacted at 15° C. for 4 hours. The deposit obtained by throwing in this reaction solution in water (500g) was separated by filtration. The precipitate was washed with isopropyl alcohol and dried under reduced pressure at 100° C. to obtain polyamic acid alkyl ester powder (11). The Mn of this polyamic acid alkyl ester was 20,200 and the Mw was 41,200.

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

*1: Polyamic acid. *2: Polyamic acid alkyl ester.

"Manufacture of liquid crystal alignment treatment agents"
In Examples 1 to 14 and Comparative Examples 1 to 4 described below, production examples of liquid crystal alignment treatment agents will be described. The liquid crystal alignment treatment agent is also used for evaluation.
The obtained liquid crystal alignment treatment agents are shown in Tables 2 to 4.
"Storage stability test for liquid crystal alignment agents"
A storage stability test was conducted using the liquid crystal alignment treatment agents obtained in Examples and Comparative Examples. Specifically, the liquid crystal alignment treatment agent was pressure-filtered with a membrane filter having a pore size of 1 μm and stored at −15° C. for 72 hours. Then, by visual observation, it was confirmed that turbidity and precipitates were generated in the liquid crystal alignment treatment agent. As a result, all the liquid crystal alignment treatment agents of Examples and Comparative Examples were uniform solutions without turbidity or precipitates.

"Adhesion evaluation"
The liquid crystal alignment treatment agents obtained in Examples and Comparative Examples were applied on the ITO surface of a 100 mm×100 mm PET electrode-attached PET substrate (length: 100 mm, width: 100 mm, thickness: 0.1 mm) washed with pure water. Application was performed by spin coating, and heat treatment was performed on a hot plate at 120° C. for 2 minutes to obtain an ITO substrate with a liquid crystal alignment film having a thickness of 100 nm. Two ITO substrates with the liquid crystal alignment film were prepared and cut into a size of 100×20 mm (length×width).

Next, a 6 μm spacer is applied to the liquid crystal alignment film surface of one substrate, and a sealant (723K1, manufactured by Kyoritsu Chemical Industry Co., Ltd.) is applied to the liquid crystal alignment film surface of the other substrate. The bonding was performed so that the liquid crystal alignment film surfaces of the substrates face each other. At that time, the application amount of the sealing agent was adjusted so that the area of the sealing agent after the bonding was 5×50 mm (length×width). Then, the bonded substrates are irradiated with 3 J/cm 2 of ultraviolet rays at a wavelength of 365 nm by using a metal halide lamp with an illuminance of 20 mW/cm ² , and then heated at 120° C. for 60 minutes in a heat circulation type clean oven. After the treatment, a cell for evaluation of adhesion was produced.
The evaluation of the adhesiveness was performed using a tabletop precision universal testing machine (AGS-X 500N, manufactured by Shimadzu Corporation). Specifically, after fixing the upper and lower ends of the obtained cell, the breaking strength (N) when pulled in the vertical direction was measured. In the evaluation, the larger the value of the breaking strength, the more excellent the adhesion is, that is, the more excellent this evaluation is.
The results are shown in Tables 5 to 7.

"Production of liquid crystal display element and evaluation of constant temperature and humidity resistance"
The liquid crystal alignment treatment agents obtained in Examples and Comparative Examples were pressure-filtered with a membrane filter having a pore size of 1 μm, and washed with pure water and IPA. A substrate with ITO electrodes (length 40 mm×width 30 mm, thickness) (0.7 mm) ITO surface is spin-coated, and heat-treated at 120° C. for 2 minutes on a hot plate and at 230° C. for 30 minutes in a heat circulation type clean oven to have a liquid crystal alignment film with a thickness of 100 nm. The ITO substrate of was obtained. Next, the liquid crystal alignment film surface of this substrate was rubbed with a rubbing device having a roll diameter of 120 mm under the conditions of a roll rotation speed of 500 rpm, a roll advancing speed of 30 mm/sec, and a pushing amount of 0.3 mm. Processed.

Then, two substrates after the rubbing treatment are prepared, a spacer of 4 μm is applied to the liquid crystal alignment film surface of one substrate, and a sealant (XN- 1500T) (manufactured by Kyoritsu Kagaku Sangyo Co., Ltd.) was applied, and the substrates were laminated so that the liquid crystal alignment film surfaces of these substrates face each other. At that time, the substrates were laminated so that the rubbing directions of the substrates were opposite to each other. Next, heat treatment was performed at 120° C. for 90 minutes in a heat circulation type clean oven to prepare an empty cell. Liquid crystal was injected into this empty cell by a reduced pressure injection method, and the injection port was sealed to obtain a liquid crystal cell. In Examples 1 to 5 and 14 and Comparative Examples 1 and 2, a positive type liquid crystal (MLC-2003) (manufactured by Merck) was used as the liquid crystal, and in Examples 6 to 13 and Comparative Examples 3 and 4, the liquid crystal was used. Negative liquid crystal (MLC-6608, manufactured by Merck) was used.

From observation with a polarization microscope (ECLIPSE E600WPOL, manufactured by Nikon Corporation), it was confirmed that all the liquid crystal cells obtained in Examples and Comparative Examples exhibited uniform liquid crystal alignment.
Then, the liquid crystal cell was stored in a constant temperature and constant humidity chamber at a temperature of 80° C. and a humidity of 90% RH for 48 hours, and peeling of the liquid crystal cell and the presence or absence of bubbles were confirmed. Specifically, the liquid crystal cell is not peeled (a state where it is peeled between the liquid crystal alignment film and the sealant and between the liquid crystal alignment film and the ITO electrode), and bubbles are generated in the liquid crystal cell. Those which were not evaluated were considered to be excellent in this evaluation (good display in the table). At that time, in Examples 1 to 3, 6 to 9, 11, and 12, in addition to the standard test described above, as an emphasized test, after storing for 144 hours in a constant temperature and humidity chamber at a temperature of 80° C. and a humidity of 90% RH, I also checked. The evaluation method is the same as above.
The results are shown in Tables 5 to 7.

<Example 1>
A1 (0.20 g), NMP (23.8 g) and BCS (7.83 g) were added to the polyamic acid solution (1) (10.0 g) obtained in Synthesis Example 1, and the mixture was stirred at 25° C. for 15 hours. Thus, a liquid crystal alignment treatment agent (1) was obtained.
<Example 2>
A1 (0.20 g), NMP (23.8 g) and BCS (7.83 g) were added to the polyamic acid solution (2) (10.0 g) obtained in Synthesis Example 2, and the mixture was stirred at 25° C. for 15 hours. Thus, a liquid crystal alignment treatment agent (2) was obtained.

<Example 3>
A1 (0.20 g), K2 (0.13 g), NMP (23.8 g) and BCS (7.83 g) were added to the polyamic acid solution (2) (10.0 g) obtained in Synthesis Example 2, The mixture was stirred at 25°C for 15 hours to obtain a liquid crystal alignment treatment agent (3).
<Example 4>
A1 (0.13 g), NMP (19.9 g) and BCS (11.8 g) were added to the polyamic acid solution (3) (10.0 g) obtained in Synthesis Example 3, and the mixture was stirred at 25° C. for 15 hours. Thus, a liquid crystal alignment treatment agent (4) was obtained.

<Example 5>
NEP (31.3 g) was added to the polyimide powder (4) (2.50 g) obtained in Synthesis Example 4, and the mixture was stirred at 60° C. for 24 hours to be dissolved. A1 (0.13 g) and BCS (7.83 g) were added to this solution, and the mixture was stirred at 25° C. for 15 hours to obtain a liquid crystal alignment treatment agent (5).
<Example 6>
A1 (0.18 g), NMP (16.0 g) and BCS (15.7 g) were added to the polyamic acid solution (5) (10.0 g) obtained in Synthesis Example 5, and the mixture was stirred at 25° C. for 15 hours. Thus, a liquid crystal alignment treatment agent (6) was obtained.

<Example 7>
A1 (0.18 g), NMP (16.0 g) and BCS (15.7 g) were added to the polyamic acid solution (6) (10.0 g) obtained in Synthesis Example 6, and the mixture was stirred at 25° C. for 15 hours. Thus, a liquid crystal alignment treatment agent (7) was obtained.
<Example 8>
NEP (23.5 g) was added to the polyimide powder (7) (2.50 g) obtained in Synthesis Example 7, and the mixture was stirred at 60° C. for 24 hours to be dissolved. A1 (0.13 g), BCS (7.83 g) and PB (7.83 g) were added to this solution, and the mixture was stirred at 25° C. for 15 hours to obtain a liquid crystal alignment treatment agent (8).

<Example 9>
NEP (23.5 g) was added to the polyimide powder (7) (2.50 g) obtained in Synthesis Example 7, and the mixture was stirred at 60° C. for 24 hours to be dissolved. A1 (0.13 g), K1 (0.18 g), BCS (7.83 g) and PB (7.83 g) were added to this solution, and the mixture was stirred at 25° C. for 15 hours to prepare a liquid crystal alignment treatment agent (9). Got
<Example 10>
A1 (0.08 g), NMP (12.1 g), BCS (11.8 g) and PB (7.83 g) were added to the polyamic acid solution (8) (10.0 g) obtained in Synthesis Example 8, The mixture was stirred at 25°C for 15 hours to obtain a liquid crystal alignment treatment agent (10).

<Example 11>
A1 (0.25 g), NMP (16.0 g) and BCS (15.7 g) were added to the polyamic acid solution (9) (10.0 g) obtained in Synthesis Example 9, and the mixture was stirred at 25° C. for 15 hours. Thus, a liquid crystal alignment treatment agent (11) was obtained.
<Example 12>
To the polyamic acid solution (9) (10.0 g) obtained in Synthesis Example 9, A1 (0.25 g), K2 (0.08 g), NMP (16.0 g) and BCS (15.7 g) were added, The mixture was stirred at 25°C for 15 hours to obtain a liquid crystal alignment treatment agent (12).

<Example 13>
In the polyamic acid solution (10) (10.0 g) obtained in Synthesis Example 10, A1 (0.08 g), K1 (0.18 g), NMP (16.0 g), BCS (7.83 g) and PB( 7.83 g) was added and the mixture was stirred at 25° C. for 15 hours to obtain a liquid crystal alignment treatment agent (13).
<Example 14>
NMP (31.3 g) was added to the polyamic acid alkyl ester powder (11) (2.50 g) obtained in Synthesis Example 11 and dissolved by stirring at 40° C. for 24 hours. A1 (0.13 g) and BCS (7.83 g) were added to this solution, and the mixture was stirred at 25° C. for 15 hours to obtain a liquid crystal alignment treatment agent (14).

<Comparative Example 1>
NMP (23.8 g) and BCS (7.83 g) were added to the polyamic acid solution (1) (10.0 g) obtained in Synthesis Example 1, and the mixture was stirred at 25° C. for 15 hours to prepare a liquid crystal alignment treatment agent ( 15) was obtained.
<Comparative example 2>
NEP (31.3 g) was added to the polyimide powder (4) (2.50 g) obtained in Synthesis Example 4, and the mixture was stirred at 60° C. for 24 hours to be dissolved. BCS (7.83 g) was added to this solution, and the mixture was stirred at 25° C. for 15 hours to obtain a liquid crystal alignment treatment agent (16).

<Comparative example 3>
NMP (16.0 g) and BCS (15.7 g) were added to the polyamic acid solution (5) (10.0 g) obtained in Synthesis Example 5, and the mixture was stirred at 25° C. for 15 hours to prepare a liquid crystal alignment treatment agent ( 17) was obtained.
<Comparative example 4>
NEP (23.5 g) was added to the polyimide powder (7) (2.50 g) obtained in Synthesis Example 7, and the mixture was stirred at 60° C. for 24 hours to be dissolved. BCS (7.83 g) and PB (7.83 g) were added to this solution, and the mixture was stirred at 25° C. for 15 hours to obtain a liquid crystal alignment treatment agent (18).

<Examples 1 to 14 and Comparative Examples 1 to 4>
Using the liquid crystal alignment treatment agents (1) to (18) obtained above, "adhesion evaluation" and "production of liquid crystal display element and evaluation of constant temperature and humidity resistance" were performed under the above conditions.
No abnormalities such as turbidity or precipitation were observed in any of the liquid crystal alignment treatment agents (1) to (18), and it was confirmed that they were uniform solutions.

*3: Indicates the content (parts by mass) of the specific compound with respect to 100 parts by mass of the polymer.
*4: Indicates the content (parts by mass) of the crosslinkable compound with respect to 100 parts by mass of the polymer.

*5: A very small amount of bubbles were found in the device.
*6: A small amount of bubbles were found in the element (more than *5).
*7: Bubbles were found in the element (more than *6).

As can be seen from the above results, the examples using the liquid crystal alignment treatment agent containing the specific compound were excellent in adhesiveness as compared with the comparative examples of the liquid crystal alignment treatment agent not containing it, and the liquid crystal cell was Even when stored under high humidity for a long time, the liquid crystal cell did not peel off. Specifically, in comparison under the same conditions, comparison between Example 1 and Comparative Example 1, comparison between Example 5 and Comparative Example 2, comparison between Example 6 and Comparative Example 3, and Example 8 And Comparative Example 4.

When a polyimide-based polymer is used as the polymer, the polymer terminal has a structure of a carboxylic acid anhydride or a dicarboxylic acid, that is, during the polymerization reaction of a diamine component and a tetracarboxylic acid component, a tetracarboxylic acid Those in which the total number of moles of the components is larger than the number of moles of the diamine component have a polymer terminal having a structure of an amino group (in the polymerization reaction, the total number of moles of the tetracarboxylic acid component is smaller than the number of moles of the diamine component. The occurrence of bubbles in the liquid crystal cell in the emphasis test was suppressed as compared with that of No. Specifically, in comparison under the same conditions, there are comparison between Example 1 and Example 2 and comparison between Example 6 and Example 7.

In addition, when a crosslinkable compound was introduced into the liquid crystal alignment treatment agent, no bubbles were generated in the liquid crystal cell in the emphasis test. Specifically, in the comparison under the same conditions, there are a comparison between Example 2 and Example 3, a comparison between Example 8 and Example 9, and a comparison between Example 11 and Example 12.

By using the liquid crystal alignment film obtained from the liquid crystal alignment treatment agent of the present invention, the adhesiveness between the substrates of the liquid crystal display device is high, further, even in a harsh environment exposed to high temperature and high humidity for a long time, The liquid crystal display device capable of suppressing the generation of bubbles in the liquid crystal display device and the peeling of the device is particularly obtained. Therefore, it can be suitably used for a liquid crystal display element for mobile devices such as smartphones and mobile phones.
The entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2018-246261 filed on Dec. 27, 2018 are cited herein as disclosure of the specification of the present invention. , Take in.

Claims (13)

1. A liquid crystal alignment treatment agent comprising a compound having a group represented by the following formula [1].
   

   

   (* represents a binding site with another structure.)
2. The liquid crystal alignment treatment agent according to claim 1, wherein the compound having a group represented by the formula [1] is a compound represented by the following formula [1a].
   

   

   ^{(X 1} is represented by the following formula [1-a] ~ formula [1-k] consisting of indicating at least one selected from the group .X ² represents a single bond or an organic group having a carbon number of 1 ~ 18 .X ³ Represents the above formula [1].
   

   

   ^{(T A} represents an alkyl group having 1 to 3 carbon atoms.)
3. The liquid crystal alignment treatment agent according to claim 2, wherein the compound represented by the formula [1a] is a compound represented by the following formula A1.
   

   
4. Any one of claims 1 to 3 containing at least one polymer selected from the group consisting of acrylic polymer, methacrylic polymer, novolac resin, polyhydroxystyrene, polyimide precursor, polyimide, polyamide, polyester, cellulose, and polysiloxane. The liquid crystal alignment treatment agent according to item 1.
5. The liquid crystal alignment treatment agent according to any one of claims 1 to 3, containing a polyimide precursor obtained by a reaction of a diamine component and a tetracarboxylic acid component or a polymer made of a polyimide obtained by imidizing the polyimide precursor. ..
6. 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 in the reaction between the diamine component and the tetracarboxylic acid component. Liquid crystal alignment treatment agent.
7. 7. The liquid crystal alignment treatment according to claim 4, wherein the compound having a group represented by the formula [1] is contained in an amount of 0.1 to 30 parts by mass based on 100 parts by mass of the polymer. Agent.
8. Furthermore, a crosslinkable compound selected from an epoxy group, an isocyanate group, an oxetane group and a cyclocarbonate group, a crosslinkable compound selected from the group consisting of a hydroxyl group, a hydroxyalkyl group and an alkoxyalkyl group having 1 to 3 carbon atoms, or a polymerizable compound. 8. The liquid crystal alignment treatment agent according to claim 1, containing at least one crosslinkable compound selected from crosslinkable compounds having an unsaturated bond group.
9. The liquid crystal alignment treatment agent according to claim 8, wherein the crosslinkable compound is a compound represented by the following formula K1 or K2.
   

   
10. The liquid crystal alignment treatment agent according to claim 8 or 9, wherein the crosslinkable compound is contained in an amount of 0.1 to 100 parts by mass based on 100 parts by mass of the polymer.
11. A liquid crystal alignment film obtained from the liquid crystal alignment treatment agent according to any one of claims 1 to 10.
12. A liquid crystal display device having the liquid crystal alignment film according to claim 11.
13. The liquid crystal display element according to claim 12, which is a mobile device.