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Method for producing liquid crystal alignment film, liquid crystal alignment film, and liquid crystal display element

A technology of liquid crystal alignment film and manufacturing method, applied in coating, instrument, optics and other directions, can solve the problems of small anisotropy, inability to obtain sufficient liquid crystal alignment, etc., and achieve the effect of reducing afterimages

Active Publication Date: 2017-12-19
NISSAN CHEM CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0009] However, the liquid crystal aligning film obtained by the photo-alignment method has a problem that the anisotropy with respect to the orientation direction of the polymer film is smaller than that of the liquid crystal aligning film obtained by the rubbing method.
If the anisotropy is small, sufficient liquid crystal orientation cannot be obtained, and when it is used as a liquid crystal display element, problems such as image sticking will occur.
[0010] In addition, as a method of improving the anisotropy of the liquid crystal alignment film obtained by the photo-alignment method, it is proposed to remove the aforementioned polyimide due to light irradiation by washing or heating with a water-soluble organic solvent after light irradiation. Proposals for low molecular weight components produced by cleavage of the main chain of amines, but image sticking has not yet been suppressed (see Patent Document 2)

Method used

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  • Method for producing liquid crystal alignment film, liquid crystal alignment film, and liquid crystal display element
  • Method for producing liquid crystal alignment film, liquid crystal alignment film, and liquid crystal display element
  • Method for producing liquid crystal alignment film, liquid crystal alignment film, and liquid crystal display element

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Embodiment

[0227] Hereinafter, the present invention will be described in more detail with examples given, but the present invention is not limited thereto.

[0228] The abbreviations of the compounds used in Examples and Comparative Examples and the measurement methods of each property are as follows.

[0229] NMP: N-methyl-2-pyrrolidone

[0230] GBL: γ-butyrolactone

[0231] BCS: Butyl Cellosolve

[0232] IPA: 2-propanol

[0233] DA-2: the following formula (DA-2) (Boc group represents a tert-butoxycarbonyl group)

[0234] Additive A: N-α-(9-fluorenylmethoxycarbonyl)-N-τ-tert-butoxycarbonyl-L-histidine

[0235] 【Chemical 29】

[0236]

[0237] The evaluation methods for viscosity, molecular weight, imidization rate, liquid crystal cell production, and image sticking caused by long-term AC driving are given below.

[0238] [viscosity]

[0239] In the synthesis example, the viscosity of the polyamic acid ester and the polyamic acid solution was measured using an E-type viscomete...

Synthetic example 1

[0263] In a 3000mL four-neck flask equipped with a stirring device and a nitrogen inlet tube, take 124.60g (510mmol) of 1,2-bis(4-aminophenoxy)ethane and 0.95g (90.0mmol) of DA-2, and 2,236 g of NMP was added, and stirred while feeding nitrogen gas to dissolve it. While stirring the diamine solution, 130.06 g (580.2 mmol) of 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride was added, and NMP was added so that the solid content concentration became 10 % by mass, and stirred at room temperature for 24 hours to obtain a solution of polyamic acid (PAA-2). The viscosity of this polyamic acid solution at a temperature of 25° C. was 511 mPa·s. In addition, the molecular weight of this polyamic acid is Mn=19100, Mw=46880.

Synthetic example 2

[0265] 200 g of the obtained polyamic acid solution (PAA-2) was taken into a 500-mL four-necked flask equipped with a stirring device and a nitrogen gas inlet tube, 85.68 g of NMP was added, and stirred for 30 minutes. 22.22 g of acetic anhydride and 6.86 g of pyridine were added to the obtained polyamic acid solution, and it heated at 50 degreeC for 3 hours, and chemically imidized it. The obtained reaction solution was poured into 1100 g of methanol while stirring, and the deposited precipitate was filtered out, followed by washing with 1100 g of methanol three times and washing with 200 g of methanol twice. The resulting resin powder was dried at 60° C. for 12 hours, whereby a polyimide resin powder was obtained.

[0266] The imidization rate of this polyimide resin powder was 68%, and the molecular weight was Mn=9155, and Mw=21430.

[0267] Then, in a 200mL sample tube equipped with a stirring bar, 12.53g of the obtained polyimide resin powder was taken, 91.89g of NMP was...

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Abstract

Provided is a method for producing a photoalignment liquid crystal alignment film which is capable of minimizing afterimages resulting from AC driving. Polarized radiation is applied to a film obtained by applying and sintering a liquid crystal alignment agent, which contains at least one type of polymer selected from a group comprising polyimide precursors represented by formula (1) and imidized polymers of said polyimide precursors, on a substrate. After the film has been brought into contact with an organic solvent having a boiling point of 110 to 180°C, the film is then brought into contact with water or a water-soluble organic solvent having a boiling point of 50 to 105°C before being treated with heat at 150°C or above. (X1 represents the formula (XA-1); Y1 represents a divalent organic group; R1 represents H or the like; and R3 to R6 represent H or the like.)

Description

technical field [0001] This invention relates to the manufacturing method of the liquid crystal aligning film for photo-alignment methods, the liquid crystal aligning film obtained by this manufacturing method, and the liquid crystal display element provided with the obtained liquid crystal aligning film. Background technique [0002] In liquid crystal display elements used in liquid crystal televisions, liquid crystal displays, etc., a liquid crystal aligning film for controlling the alignment state of liquid crystals is usually provided in the element. [0003] At present, the most popular liquid crystal alignment film in the industry is a film composed of polyimide formed of polyamic acid and / or its imide formed on the electrode substrate by using cloth such as cotton, nylon, polyester, etc. It is made by wiping the surface in one direction, which is called rubbing treatment. [0004] The film surface rubbing treatment method in the orientation process of a liquid crysta...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G02F1/1337C08G73/10
CPCC08G73/10G02F1/133723G02F1/133788C08G73/1042C08G73/105C08G73/1078C09D179/08
Inventor 作本直树饭沼洋介野口勇步堀隆夫山极大辉
Owner NISSAN CHEM CORP
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