CN113861417A - Liquid crystal alignment agent, liquid crystal display panel and preparation method thereof - Google Patents

Liquid crystal alignment agent, liquid crystal display panel and preparation method thereof Download PDF

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CN113861417A
CN113861417A CN202111163527.2A CN202111163527A CN113861417A CN 113861417 A CN113861417 A CN 113861417A CN 202111163527 A CN202111163527 A CN 202111163527A CN 113861417 A CN113861417 A CN 113861417A
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兰松
陈黎暄
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TCL China Star Optoelectronics Technology Co Ltd
TCL Huaxing Photoelectric Technology Co Ltd
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    • C—CHEMISTRY; METALLURGY
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    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
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    • C08G73/06—Polycondensates having nitrogen-containing heterocyclic rings in the main chain of the macromolecule
    • C08G73/10—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
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    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
    • G02F1/133711—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers by organic films, e.g. polymeric films
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Abstract

The application discloses a liquid crystal alignment agent, a liquid crystal display panel and a preparation method thereof. The liquid crystal alignment agent comprises at least one polymer. The liquid crystal alignment agent has excellent liquid crystal alignment performance, and can realize alignment of liquid crystals under ultraviolet irradiation with lower energy.

Description

Liquid crystal alignment agent, liquid crystal display panel and preparation method thereof
Technical Field
The application relates to the technical field of display, in particular to a liquid crystal alignment agent, a liquid crystal display panel and a preparation method thereof.
Background
Liquid Crystal Displays (LCDs) are widely used for televisions, various displays, and the like. As a display element of a Liquid Crystal Display (LCD), there are liquid crystal cells of Twisted Nematic (TN) type, Super Twisted Nematic (STN) type, in-plane Switching (IPS) type, and the like; a Fringe Field Switching (FFS) type, in which the numerical aperture of a display element portion is increased to improve luminance by changing the electrode structure of an IPS type or the like, is also known.
In the constitution of these displays, the liquid crystal alignment film is an important factor concerning the quality of liquid crystal display. In order to obtain uniform display characteristics of the lcd, the alignment film needs to align the liquid crystal molecules uniformly so that the liquid crystal molecules are aligned uniformly in one direction and form a pre-tilt angle with the substrate surface.
There are two methods currently available to achieve this: one is a rubbing method, in which a liquid crystal alignment film is rubbed in one direction using a cloth of nylon, rayon, or polyester fibers to perform a surface treatment, thereby aligning liquid crystal molecules, but the rubbing method causes problems such as dust and static electricity; another method is a photo-alignment method, in which a coating film formed of a liquid crystal aligning agent containing polyamic acid or the like imparts liquid crystal aligning ability, and higher energy is often required to realize the aligning function of the liquid crystal aligning agent.
Therefore, it is desirable to provide a liquid crystal aligning agent with good alignment function.
Disclosure of Invention
The present application aims to provide a liquid crystal alignment agent having a good alignment function, and which can realize the alignment function under light irradiation of low energy.
The application provides a liquid crystal alignment agent, which comprises at least one polymer, wherein the polymer has a structure shown in a formula (1):
Figure BDA0003290999660000021
wherein R is independently selected from C1～C5Or a substituted or unsubstituted C1～C5Linear or branched alkanes of (a); n is independently selected from an integer of 20 to 200;
a has the general formula:
Figure BDA0003290999660000022
are attachment sites.
Optionally, in some embodiments herein, B is independently selected from a single bond (e.g., a carbon-carbon single bond), a substituted or unsubstituted aromatic group, a substituted or unsubstituted heteroaromatic group, a substituted or unsubstituted straight chain alkyl group having 1 to 8 carbon atoms, a substituted or unsubstituted branched or cyclic alkyl group having 1 to 8 carbon atoms, a substituted or unsubstituted straight chain alkoxy group having 1 to 8 carbon atoms, a substituted or unsubstituted branched or cyclic alkoxy group having 1 to 8 carbon atoms, a ketone group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, a thioalkoxy group having 1 to 8 carbon atoms; an aryloxycarbonyl group having 1 to 8 carbon atoms.
Optionally, in some embodiments of the present application, a is selected from any one of the following structures:
Figure BDA0003290999660000031
wherein, is the attachment site.
Optionally, in some embodiments of the present application, the number average molecular weight of the polymer is 5000 to 500000.
Optionally, in some embodiments herein, the polymer has a number average molecular weight of 10000 to 100000.
Correspondingly, the application also provides a liquid crystal alignment agent, which comprises a polymer, wherein the polymer has a structure shown in a formula (2):
Figure BDA0003290999660000032
wherein R is independently selected from a linear or branched alkyl group having 1 to 8 carbon atoms, or a substituted or unsubstituted C1～C5Linear or branched alkanes of (a); x is an integer selected from 20 to 200;
b is independently selected from a single bond (such as a carbon-carbon single bond), a substituted or unsubstituted aromatic group, a substituted or unsubstituted heteroaromatic group, a substituted or unsubstituted straight-chain alkyl group having 1 to 8 carbon atoms, a substituted or unsubstituted branched or cyclic alkyl group having 1 to 8 carbon atoms, a substituted or unsubstituted straight-chain alkoxy group having 1 to 8 carbon atoms, a substituted or unsubstituted branched or cyclic alkoxy group having 1 to 8 carbon atoms, a ketone group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, and a thioalkoxy group having 1 to 8 carbon atoms; an aryloxycarbonyl group having 1 to 8 carbon atoms.
In addition, the present application also provides a liquid crystal display panel, including:
the CF substrate and the TFT substrate are oppositely arranged;
the frame glue is arranged between the CF substrate and the TFT substrate and used for connecting the CF substrate and the TFT substrate in a sealing manner; and
the liquid crystal layer is arranged in a space enclosed by the frame glue between the CF substrate and the TFT substrate; wherein, the preparation raw material of the liquid crystal layer comprises the liquid crystal aligning agent.
In addition, the embodiment of the application also provides a preparation method of the liquid crystal display panel, which comprises the following steps:
step one, preparing alignment liquid by adopting a liquid crystal alignment agent; respectively coating the alignment liquid on the CF substrate and the TFT substrate, and drying to obtain alignment films;
step two, respectively carrying out ultraviolet irradiation on the alignment films on the CF substrate and the TFT substrate;
step three, forming a sealing layer on the CF substrate or the alignment film of the TFT substrate by adopting a sealant, and then forming a box by the CF substrate and the TFT substrate;
and step four, injecting liquid crystal under the vacuum condition to obtain a liquid crystal box with horizontal alignment, namely a liquid crystal display panel.
Optionally, in some embodiments of the present application, the drying process includes: the first baking is carried out at the temperature of 80-120 ℃ for 2-5 min, and then the second baking is carried out at the temperature of 200-250 ℃ for 20-40 min.
Optionally, in some embodiments of the present application, in the first step, the thickness of the alignment film is 80 to 120 nm.
Optionally, in some embodiments of the present application, the wavelength of the polarized ultraviolet light of the ultraviolet irradiation is 200 to 320nm, and the irradiation time is 2 to 10 min.
Optionally, in some embodiments of the present application, the energy of the ultraviolet irradiation is 100 to 500mJ/cm2。
The beneficial effect of this application lies in:
the liquid crystal alignment agent has excellent liquid crystal alignment performance, and can realize the alignment of liquid crystals under the illumination of lower energy (about 200 mj).
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In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a liquid crystal display panel provided in an embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The embodiment of the application provides a liquid crystal alignment agent, a liquid crystal display panel and a preparation method thereof. The following are detailed below. It should be noted that the following description of the embodiments is not intended to limit the preferred order of the embodiments. In addition, in the description of the present application, the term "including" means "including but not limited to". The terms first, second, third and the like are used merely as labels, and do not impose numerical requirements or an established order. Various embodiments of the invention may exist in a range of versions; it is to be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention; accordingly, the described range descriptions should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range. For example, it is contemplated that the description of a range from 1 to 6 has specifically disclosed sub-ranges such as, for example, from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as individual numbers within a range such as, for example, 1, 2, 3, 4, 5, and 6, as applicable regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any number (fractional or integer) recited within the indicated range.
In the course of research and practice on the prior art, the inventors of the present application found that a photoalignment method using photoisomerization or photodimerization, photodecomposition, or the like, as a technique instead of the rubbing method. The method of the photoalignment method: imparting anisotropy to a film by irradiating a radiation-sensitive organic thin film formed on a substrate with polarized or unpolarized radiation, thereby controlling the alignment of liquid crystal molecules; compared with the rubbing method, the generation of display defects or the reduction of yield due to dust or the like can be suppressed. In addition, the photo-alignment method has an advantage that liquid crystal alignment ability can be uniformly given to an organic thin film formed on a substrate.
The embodiment of the application provides a liquid crystal alignment agent, which comprises at least one polymer, wherein the polymer has a structure shown in a formula (1):
Figure BDA0003290999660000061
wherein R is independently selected from C1～C5Or a substituted or unsubstituted C1～C5Linear or branched alkanes of (a); n is independently selected from an integer of 20 to 200;
the structural general formula of A is as follows:
Figure BDA0003290999660000062
wherein, is the attachment site.
That is, the polymer has a structure as
Figure BDA0003290999660000063
The structure shown.
Further, according to the above formula, it is known that B is a group for linking the structures on both sides thereof; it is also understood that B is selected from structures as long as the connection of the two-sided structure is achieved. Further, B is independently selected from a single bond, a substituted or unsubstituted aromatic group, a substituted or unsubstituted heteroaromatic group, a substituted or unsubstituted straight-chain alkyl group having 1 to 8 carbon atoms, a substituted or unsubstituted branched or cyclic alkyl group having 1 to 8 carbon atoms, a substituted or unsubstituted straight-chain alkoxy group having 1 to 8 carbon atoms, a substituted or unsubstituted branched or cyclic alkoxy group having 1 to 8 carbon atoms, a ketone group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, a thioalkoxy group having 1 to 8 carbon atoms; an aryloxycarbonyl group having 1 to 8 carbon atoms.
Further, a is selected from, but not limited to, any one of the following structures:
Figure BDA0003290999660000071
wherein, is the attachment site.
The number average molecular weight of the polymer is 5000-500000. Further, the number average molecular weight of the polymer is 10000-100000.
In one embodiment, a liquid crystal alignment agent is provided, which includes a polymer having a structure represented by formula (2):
Figure BDA0003290999660000072
wherein R is independently selected from a linear or branched alkyl group having 1 to 8 carbon atoms, or a substituted or unsubstituted C1～C5Linear or branched alkanes of (a); x is an integer selected from 20 to 200.
Compared with the formula (1), the dehydration condensation cyclization of-NH-and-OH in the formula (2) is the structure shown in the formula (1).
Further, B is independently selected from a single bond, a substituted or unsubstituted aromatic group, a substituted or unsubstituted heteroaromatic group, a substituted or unsubstituted straight-chain alkyl group having 1 to 8 carbon atoms, a substituted or unsubstituted branched or cyclic alkyl group having 1 to 8 carbon atoms, a substituted or unsubstituted straight-chain alkoxy group having 1 to 8 carbon atoms, a substituted or unsubstituted branched or cyclic alkoxy group having 1 to 8 carbon atoms, a ketone group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, a thioalkoxy group having 1 to 8 carbon atoms; an aryloxycarbonyl group having 1 to 8 carbon atoms.
Further, the number average molecular weight of the polymer may be 5000 to 500000; for example, the number average molecular weight of the polymer may be 5000, 100000, 150000, 200000, 250000, 300000, 350000, 400000, 450000, or 500000.
In one embodiment, the structure of the polymer may be as follows:
Figure BDA0003290999660000081
a. b is independently selected from an integer of 20 to 200, for example 20, 30, 50, 80, 100, 120, 150, 180, 190 or 200.
Still further, the structure of the polymer may be as follows:
Figure BDA0003290999660000082
a. b is independently selected from an integer of 20 to 200.
For example, the structure of the polymer may be as follows:
Figure BDA0003290999660000091
m and n are independently selected from integers from 20 to 200.
In the present application, the reactants for synthesizing the polymer include diamines and anhydrides, which are represented by the following structures:
Figure BDA0003290999660000092
further, the anhydride is selected from, but not limited to, one or more of the following structures:
Figure BDA0003290999660000093
in the present application, the synthesis method of the polymer may be: diamine compounds and acid anhydride are adopted for polymerization reaction to prepare polyimide, and then the liquid crystal alignment agent is obtained.
Figure BDA0003290999660000101
For example, in one embodiment, diamines of the formula:
Figure BDA0003290999660000102
further, one or more acid anhydrides may be used in the synthesis of the polymer without limitation. For example, if two anhydrides are used, 1: a molar ratio of 1 was used.
An embodiment of the present invention further provides a liquid crystal display panel 100, please refer to fig. 1, including:
the CF substrate 110 and the TFT substrate 120 disposed opposite to each other;
the sealant 130 is arranged between the CF substrate 110 and the TFT substrate 120 and is used for hermetically connecting the CF substrate and the TFT substrate; and
a liquid crystal layer 140 disposed in a space surrounded by the sealant 130 between the CF substrate 110 and the TFT substrate 120; the liquid crystal layer 140 includes an alignment film 141 and liquid crystal molecules 142, wherein the alignment film 141 is made of the liquid crystal alignment agent of the present application.
The preparation method of the liquid crystal display panel comprises the following steps:
step one, preparing alignment liquid by adopting a liquid crystal alignment agent; respectively coating the alignment liquid on the CF substrate and the TFT substrate, and drying to obtain alignment films;
step two, respectively carrying out ultraviolet irradiation on the alignment films on the CF substrate and the TFT substrate;
step three, forming a sealing layer on the CF substrate or the alignment film of the TFT substrate by adopting a sealant, and then forming a box by the CF substrate and the TFT substrate;
and step four, injecting liquid crystal under the vacuum condition to obtain a liquid crystal box with horizontal alignment, namely a liquid crystal display panel.
Further, the drying process comprises: firstly, baking for the first time at the temperature of 80-120 ℃ for 2-5 min; and then carrying out secondary baking at the temperature of 200-250 ℃ for 20-40 min. In the first step, the thickness of the alignment film is 80-120 nm.
Furthermore, the wavelength of polarized ultraviolet rays of the ultraviolet irradiation is 200-320 nm, and the irradiation time is 2-10 min. The energy of the ultraviolet irradiation is 100-500 mJ/cm2. In addition, if the wavelength of ultraviolet ray is provided>320nm, too long wavelength leads to the effect of no time photodecomposition, thus leading to poor alignment; wavelength of ultraviolet rays<200nm, too short wavelength, which causes too short wavelength of light, easily causes breakage of other molecular bonds in the alignment film.
More specifically, the preparation process of the liquid crystal display panel may be:
(1) taking the prepared polyimide solution synthesized by the method, spin-coating the polyimide solution on a 2 x 2cm ITO comb-shaped glass substrate, spin-coating a substrate without ITO, baking the substrate at 80-120 ℃ for 2-5 min, and baking the substrate at 200-250 ℃ for 20-40 min; the thickness of the obtained polyimide film is about 100 nm;
(2) the above substrates were irradiated with 100mJ/cm of light, respectively2Irradiating with polarized ultraviolet rays of 200-320 nm for 5 min;
(3) coating sealant on the surface of one ITO substrate, and assembling the ITO substrate with the other ITO substrate;
(4) then, the liquid crystal is injected in vacuum. A horizontally aligned liquid crystal cell is obtained.
The polymer in the liquid crystal alignment agent has the characteristic of photo-cracking, and the structure of the polymer can be photo-cracked through UV light irradiation under the wavelength of 200-320 nm, so that the purpose of uniform directional arrangement is achieved. In particular, reference may be made to the following specific reaction procedures:
Figure BDA0003290999660000111
for example,
Figure BDA0003290999660000112
wherein, the cracked structure has an alignment function, as follows:
Figure BDA0003290999660000121
the present application has been repeated several times, and the present invention will now be described in further detail with reference to some test results, which will be described in detail below with reference to specific examples.
Example 1
The embodiment provides a liquid crystal aligning agent, which is a polyimide material and has the following structure:
Figure BDA0003290999660000122
wherein m and n are independently selected from integers of 20 to 200.
The synthesis of the polyimide comprises the following steps:
step one, 6.52g (40mmol) of 4ACA is dissolved in 160mL of acetone, 4mL of 12mol/L concentrated hydrochloric acid is dropwise added into 4ACA acetone solution, and acetone is removed after the reaction is finished to obtain 4ACA hydrochloride powder;
then irradiating the 4ACA hydrochloride powder with 100W high-pressure mercury lamp and a filter of 250-450 nm at intensity of 2.7mW/cm3The duration is 30-40 minutes, and the induction is [2+2 ]]Performing a cycloaddition reaction to obtain 4ATA dihydrochloride;
the 4ATA dihydrochloride (6.00g, 15.04mmol) was reacted with trimethylsilylchloride (TMSCl) (3.26g, 10.16mmol) and methanol (24.40mL, 0.64mol) under nitrogen at room temperatureMixing and reacting under atmosphere; the reaction mixture was precipitated and dissolved in water, followed by extraction with ethyl acetate; the collected ethyl acetate organic layer was over MgSO4Dried and then evaporated and neutralized with 1N NaOH to give the product: 4ATA ester;
the structure of the 4ACA in this embodiment is:
Figure BDA0003290999660000131
further, the synthesis process of step one refers to the following chemical reaction formula:
Figure BDA0003290999660000132
in this example, R ═ CH3I.e. the structure of the 4ATA ester is shown below:
Figure BDA0003290999660000133
1H NMR(400MHz,DMSO-d6,δ,ppm):0.84(t,6H,J＝7.0Hz),3.68(dd,2H,J＝7.2,7.2Hz),3.73(q,4H,J＝6.8,7.6Hz),4.10(dd,2H,J＝7.2,7.6Hz),4.96(S,4H),6.49(d,4H,J＝8.4Hz),6.95(d,4H,J＝8.4Hz)；13C NMR(400MHz,DMSO-d6,δ,ppm):13.7,40.3,46.5,59.6,113.5,125.7,128.1,147.3,171.6；
step two, the step of synthesizing polyimide comprises:
in a 300mL four-necked flask equipped with a stirrer and a nitrogen inlet, 1.12g (5mmol) of CA-1, 1.47g (5mmol) of CA-2, and 25.7g of NMP were mixed under a nitrogen atmosphere; 13.64g (10mmol) of 4ATA ester was added under stirring, and the mixture was stirred at 40 ℃ for 48 hours to obtain a polyamic acid solution. The polyamic acid had Mn of 11200 and Mw of 33900.
Figure BDA0003290999660000141
The polyimide of this example was synthesized according to the following chemical reaction:
Figure BDA0003290999660000142
example 2
The present embodiment provides a liquid crystal display panel, including:
the CF substrate and the TFT substrate are oppositely arranged;
the frame glue is arranged between the CF substrate and the TFT substrate and used for connecting the CF substrate and the TFT substrate in a sealing manner; and
the liquid crystal layer is arranged in a space enclosed by the frame glue between the CF substrate and the TFT substrate; wherein, the preparation raw material of the liquid crystal layer comprises any one of the liquid crystal aligning agents to form an alignment film.
The preparation method of the liquid crystal display panel comprises the following steps:
step one, preparing an alignment liquid by adopting the liquid crystal alignment agent in the embodiment 1; respectively coating the alignment liquid on a CF substrate and a TFT substrate, and baking for the first time at the temperature of 80 ℃ for 5 min; then baking for 30min at 230 ℃ for the second time to obtain an alignment film; the thickness of the alignment film is 100 nm;
step two, respectively carrying out ultraviolet irradiation on the alignment films on the CF substrate and the TFT substrate; the wavelength of polarized ultraviolet rays of the ultraviolet irradiation is 254nm, and the irradiation time is 5 min; the energy of the ultraviolet irradiation is 200 mJ;
step three, forming a sealing layer on the CF substrate or the alignment film of the TFT substrate by adopting a sealant, and then forming a box by the CF substrate and the TFT substrate;
and step four, injecting liquid crystal under the vacuum condition to obtain the liquid crystal box with horizontal alignment.
In the embodiment, after the coating formed by the alignment liquid is irradiated by UV light, the liquid crystal alignment agent in the coating can be subjected to photo-cracking, so that the alignment function is realized, and the aim of uniform directional arrangement is further fulfilled; UV light cleavage can be referred to the following specific reaction procedure:
Figure BDA0003290999660000151
example 3
The present embodiment provides a liquid crystal display panel, including:
the CF substrate and the TFT substrate are oppositely arranged;
the frame glue is arranged between the CF substrate and the TFT substrate and used for connecting the CF substrate and the TFT substrate in a sealing manner; and
the liquid crystal layer is arranged in a space enclosed by the frame glue between the CF substrate and the TFT substrate; wherein, the preparation raw material of the liquid crystal layer comprises any one of the liquid crystal aligning agents to form an alignment film.
The preparation method of the liquid crystal display panel comprises the following steps:
step one, preparing an alignment liquid by adopting the liquid crystal alignment agent in the embodiment 1; respectively coating the alignment liquid on a CF substrate and a TFT substrate, and baking for the first time for 2min at the temperature of 120 ℃; then baking for 50min for the second time at the temperature of 200 ℃ to obtain an alignment film; the thickness of the alignment film is 100 nm;
step two, respectively carrying out ultraviolet irradiation on the alignment films on the CF substrate and the TFT substrate; the wavelength of polarized ultraviolet rays for ultraviolet irradiation is 320nm, and the irradiation time is 5 min; the energy of the ultraviolet irradiation is 500 mJ;
step three, forming a sealing layer on the CF substrate or the alignment film of the TFT substrate by adopting a sealant, and then forming a box by the CF substrate and the TFT substrate;
and step four, injecting liquid crystal under the vacuum condition to obtain the liquid crystal box with horizontal alignment.
Comparative example 1
Comparative example 1 provides a conventional photocleavable polymer having the following structural formula:
Figure BDA0003290999660000161
in one embodiment, a liquid crystal display panel is provided, which includes:
the CF substrate and the TFT substrate are oppositely arranged;
the frame glue is arranged between the CF substrate and the TFT substrate and used for connecting the CF substrate and the TFT substrate in a sealing manner; and
the liquid crystal layer is arranged in a space enclosed by the frame glue between the CF substrate and the TFT substrate; wherein, the preparation raw material of the liquid crystal layer comprises the photocleavage polymer to form an alignment film.
The method for manufacturing the liquid crystal display panel of this embodiment may refer to embodiment 2.
The liquid crystal display panel was prepared by using the photo-cleavable polymer, and the specific method was as in example 2, wherein the wavelength of polarized ultraviolet rays of the ultraviolet irradiation of comparative example 1 was 254 nm.
Test example 1
This test performed ultraviolet irradiation of an alignment film formed of the liquid crystal aligning agent in example 1 of the present application, and observed the alignment effect on liquid crystal molecules, while using the photo-cleavable polymer of comparative example 1 as a control group.
The method comprises the following steps: placing the prepared panel in a constant temperature box at 80 ℃ for 200h, and evaluating by a polarizing microscope with 5 times multiplying power; the good alignment effect is good in dark state, normal lighting is achieved, and dark stripes do not exist in the pixels; otherwise, the alignment effect is poor. The experiments and the results are shown in table 1.
TABLE 1
Examples of the present invention Alignment film structure Wavelength of irradiation (Energy) Alignment effect
Experimental group 1 Example 2 254nm 200mJ Good effect
Experimental group 2 Example 3 254nm 500mJ Good effect
Control group 1 Comparative example 1 254nm 200mJ Failure of the product
Control group 2 Comparative example 1 254nm 500mJ Good effect
According to the data in table 1, it can be found that the alignment film formed by using the liquid crystal alignment agent in the embodiment of the present application can achieve the alignment effect of the liquid crystal under the condition of lower energy; the control group cannot realize the alignment effect under the condition of low-energy (200mJ) ultraviolet irradiation, and needs higher energy (500mJ) to realize the alignment effect.
In conclusion, the liquid crystal alignment agent has good liquid crystal alignment performance, and can realize the alignment function under lower illumination energy.
In the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.
The liquid crystal aligning agent, the liquid crystal display panel and the preparation method thereof provided by the embodiments of the present application are described in detail above, and the principles and embodiments of the present application are explained herein by applying specific examples, and the description of the above embodiments is only used to help understanding the method and the core ideas of the present application; meanwhile, for those skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

Claims (10)

1. A liquid crystal alignment agent is characterized by comprising at least one polymer, wherein the polymer has a structure shown in a formula (1):
Figure FDA0003290999650000011
wherein R is independently selected from C1～C5Or a substituted or unsubstituted C1～C5Linear or branched alkanes of (a); n is independently selected from an integer of 20 to 200;
the structural general formula of A is:
Figure FDA0003290999650000012
are attachment sites.
2. The liquid crystal aligning agent according to claim 1, wherein B is independently selected from a single bond, a substituted or unsubstituted aromatic group, a substituted or unsubstituted heteroaromatic group, a substituted or unsubstituted straight-chain alkyl group having 1 to 8 carbon atoms, a substituted or unsubstituted branched or cyclic alkyl group having 1 to 8 carbon atoms, a substituted or unsubstituted straight-chain alkoxy group having 1 to 8 carbon atoms, a substituted or unsubstituted branched or cyclic alkoxy group having 1 to 8 carbon atoms, a ketone group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, a thioalkoxy group having 1 to 8 carbon atoms; an aryloxycarbonyl group having 1 to 8 carbon atoms.
3. The liquid crystal aligning agent according to claim 1 or 2, wherein a is selected from any one of the following structures:
Figure FDA0003290999650000013
Figure FDA0003290999650000021
wherein, is the attachment site.
4. The liquid crystal aligning agent according to claim 1, wherein the number average molecular weight of the polymer is 5000 to 500000.
5. The liquid crystal aligning agent of claim 1, wherein the number average molecular weight of the polymer is 10000 to 100000.
6. A liquid crystal alignment agent is characterized by comprising a polymer, wherein the polymer has a structure shown as a formula (2):
Figure FDA0003290999650000022
wherein R is independently selected from a linear or branched alkyl group having 1 to 8 carbon atoms, or a substituted or unsubstituted C1～C5Linear or branched alkanes of (a); x is an integer selected from 20 to 200;
b is independently selected from a single bond, a substituted or unsubstituted aromatic group, a substituted or unsubstituted heteroaromatic group, a substituted or unsubstituted straight-chain alkyl group having 1 to 8 carbon atoms, a substituted or unsubstituted branched or cyclic alkyl group having 1 to 8 carbon atoms, a substituted or unsubstituted straight-chain alkoxy group having 1 to 8 carbon atoms, a substituted or unsubstituted branched or cyclic alkoxy group having 1 to 8 carbon atoms, a ketone group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, a thioalkoxy group having 1 to 8 carbon atoms; an aryloxycarbonyl group having 1 to 8 carbon atoms.
7. A liquid crystal display panel, comprising:
the CF substrate and the TFT substrate are oppositely arranged;
the frame glue is arranged between the CF substrate and the TFT substrate and used for connecting the CF substrate and the TFT substrate in a sealing manner; and
the liquid crystal layer is arranged in a space enclosed by the frame glue between the CF substrate and the TFT substrate; wherein the preparation raw material of the liquid crystal layer comprises the liquid crystal aligning agent as claimed in any one of claims 1 to 5, or the preparation raw material of the liquid crystal layer comprises the liquid crystal aligning agent as claimed in claim 6.
8. The preparation method of the liquid crystal display panel is characterized by comprising the following steps:
step one, preparing alignment liquid by adopting a liquid crystal alignment agent; respectively coating the alignment liquid on the CF substrate and the TFT substrate, and drying to obtain alignment films;
step two, respectively carrying out ultraviolet irradiation on the alignment films on the CF substrate and the TFT substrate;
step three, forming a sealing layer on the CF substrate or the alignment film of the TFT substrate by adopting a sealant, and then forming a box by the CF substrate and the TFT substrate;
and step four, injecting liquid crystal under the vacuum condition to obtain a liquid crystal box with horizontal alignment, namely a liquid crystal display panel.
9. The method of manufacturing a liquid crystal display panel according to claim 8, wherein the drying process includes: firstly, baking for the first time at the temperature of 80-120 ℃ for 2-5 min, and then baking for the second time at the temperature of 200-250 ℃ for 20-40 min; and/or
The thickness of the alignment film is 80-120 nm.
10. The method for manufacturing a liquid crystal display panel according to claim 8, wherein the wavelength of the polarized ultraviolet rays of the ultraviolet irradiation is 200 to 320nm, and the irradiation time is 2 to 10 min;
the energy of the ultraviolet irradiation is 100-500 mJ/cm2。
CN202111163527.2A 2021-09-30 2021-09-30 Liquid crystal alignment agent, liquid crystal display panel and preparation method thereof Pending CN113861417A (en)

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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106398721A (en) * 2015-07-27 2017-02-15 Jsr株式会社 Liquid crystal aligning agent, liquid crystal alignment film, liquid crystal device, manufacturing method for liquid crystal alignment film, polymer and diamine

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106398721A (en) * 2015-07-27 2017-02-15 Jsr株式会社 Liquid crystal aligning agent, liquid crystal alignment film, liquid crystal device, manufacturing method for liquid crystal alignment film, polymer and diamine

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