CN-121991346-A - Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element

Abstract

The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal display element. Provided are a coating film which can form a coating film having excellent uniformity of film thickness in a coating surface, linearity and dimensional stability of a coating peripheral portion, a polyimide-based liquid crystal aligning agent suitable for an inkjet method, and a liquid crystal alignment film using the same. A liquid crystal aligning agent is characterized by comprising a polymer and a solvent containing a compound represented by the following formula (a). R 1 、R 2 is independently straight-chain or branched-chain alkyl with 1-8 carbon atoms. Wherein R 1 and R 2 have a total carbon number and R 2 is 4 or more.

Inventors

• Central Plains Xiang one is bright
• Haramoto Jun
• ISHIKAWA KAZUNORI
• LI ZHUYONG

Assignees

• 日产化学株式会社

Dates

Publication Date

20260508

Application Date

20170330

Priority Date

20160331

Claims (12)

1. 1. A liquid crystal aligning agent comprising a polymer having an ability to align liquid crystals, and a solvent comprising a compound represented by the following formula (a), In the formula (a), R 1 、R 2 is independently a linear or branched alkyl group having 1 to 8 carbon atoms, wherein the total number of carbon atoms of R 1 and R 2 is 4 or more.
2. 2. The liquid crystal aligning agent according to claim 1, wherein the polymer is at least 1 polymer selected from the group consisting of a polyimide precursor obtained by a reaction of a tetracarboxylic acid derivative component and a diamine component, and a polyimide as an imide thereof.
3. 3. The liquid crystal aligning agent according to claim 1 or 2, wherein the solvent is contained in an amount of 1 to 50% by weight based on the total amount of the solvent.
4. 4. The liquid crystal aligning agent according to any one of claim 1 to 3, wherein the solvent is at least 1 selected from the group consisting of a-1~a-48, 。
5. 5. The liquid crystal aligning agent according to claim 4, wherein the solvent is a-22, a-13 to a-21, a-24, a-26, a-27, a-31, a-34, a-37, or a-38.
6. 6. The liquid crystal aligning agent according to claim 4, wherein the solvent is a-22 or a-38.
7. 7. The liquid crystal aligning agent according to any one of claims 1 to 6, wherein the solvent further contains at least 1 good solvent selected from the group consisting of N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ -butyrolactone, 3-methoxy-N, N-dimethylpropionamide and 1, 3-dimethyl-2-imidazolidinone.
8. 8. The liquid crystal aligning agent according to claim 7, wherein the good solvent is contained in an amount of 5 to 30 parts by weight based on 100 parts by weight of the specific solvent.
9. 9. The liquid crystal aligning agent according to any one of claims 1 to 8, further comprising at least 1 poor solvent selected from the group consisting of butyl cellosolve, 1-butoxy-2-propanol, butyl cellosolve acetate, dipropylene glycol monomethyl ether, diacetone alcohol, diethylene glycol diethyl ether, diisoamyl ether, propylene glycol diacetate, diisobutyl ketone, ethyl carbitol and dipropylene glycol dimethyl ether as a solvent.
10. 10. The liquid crystal aligning agent according to claim 9, wherein the poor solvent is contained in an amount of 5 to 40 parts by weight based on 100 parts by weight of the specific solvent.
11. 11. A liquid crystal alignment film obtained from the liquid crystal alignment agent according to claim 1 to 10.
12. 12. A liquid crystal display element comprising the liquid crystal alignment film according to claim 11.

Description

Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element The present application is a divisional application of chinese patent application having a filing date of 2017, 3/30, a filing number of 201780033821.7, and a name of "liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element". Technical Field The present invention relates to a liquid crystal aligning agent suitable for an inkjet film forming method and having high dimensional stability at the time of coating, a liquid crystal alignment film obtained from the liquid crystal aligning agent, and a liquid crystal display element including the liquid crystal alignment film. Background As the liquid crystal alignment film, a so-called polyimide-based liquid crystal alignment film obtained by applying a liquid crystal alignment agent containing a polyimide precursor such as polyamide acid (also referred to as polyamide acid) or a solution of a soluble polyimide as a main component and baking the applied liquid crystal alignment agent is widely used. As a film forming method of the above-mentioned liquid crystal alignment film, spin coating, dip coating, flexible printing, and the like are generally known. Among them, a coating method based on flexible printing has been used so far in most cases. However, there are problems in that various resin plates are required depending on the type of liquid crystal panel, that the plate is replaced in a manufacturing process is complicated, that film formation onto a dummy substrate is required to stabilize a film forming process, and that the manufacturing of the plate is one cause of an increase in manufacturing cost of the liquid crystal display panel. Therefore, the inkjet method is attracting attention as a film forming method of a liquid crystal alignment film without using a printing plate. The inkjet method is a method of forming a film by dropping fine droplets onto a substrate and wetting and spreading the droplets. Since the printed pattern can be freely set without using a printing plate, the manufacturing process of the liquid crystal display device can be simplified. In addition, there is no need to form a film on the dummy substrate, which is necessary for flexible printing, and there is an advantage that the waste of the coating liquid is small. By the inkjet method, cost reduction and production efficiency improvement of the liquid crystal panel can be expected. The liquid crystal alignment film formed by the inkjet method is required to have small film thickness unevenness in the coating surface and high film formation accuracy in the coating peripheral portion. In general, in a liquid crystal alignment film formed by an inkjet method, uniformity of film thickness in a coating surface is a trade-off between film formation accuracy in a coating peripheral portion. That is, the dimensional stability of the coating peripheral portion of the material having high in-plane uniformity is low, and the film protrudes from the set dimension. On the other hand, the uniformity in the coating surface of the material in which the coating peripheral portion is a straight line becomes low. In order to improve the film formation accuracy of the coating peripheral portion, a method of restricting the alignment film to a predetermined range by a special structure has been proposed (see patent documents 1 to 3). However, these methods have difficulty in requiring additional use of a special structure. Prior art literature Patent literature Patent document 1 Japanese patent application laid-open No. 2004-361623 Patent document 2 Japanese patent application laid-open No. 2008-145461 Patent document 3 Japanese patent application laid-open No. 2010-281925 Disclosure of Invention Problems to be solved by the invention In recent years, with the increase in definition of liquid crystal display elements, TFT designs of multilayer wirings have become mainstream. In this design, a contact hole (also referred to as C/H) is formed in the substrate to connect the lower layer wiring and the upper layer wiring. Accordingly, the spreadability of the liquid crystal alignment agent is easily impaired when the liquid crystal alignment agent is applied due to the influence of the wiring structure and C/H. As a result, the thickness of the alignment film may be uneven, such as dot-like unevenness or stripe-like unevenness, in the periphery of the C/H or other portions, and the liquid crystal display element may be unevenly represented. In view of the above problems, the present invention provides a liquid crystal alignment agent which can suppress the defective application of an alignment film due to the influence of a wiring structure or C/H and can suppress the defective display of a liquid crystal display element, a liquid crystal alignment film using the same, and a liquid crystal display element including the liquid crystal alignment film. Solution for solvin