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Photoreactive polymer and method for preparing the same

a photoreactive polymer and polymer technology, applied in the field of photoreactive polymers, can solve the problems of increased preparing cost, reduced contrast, and reclined yield of products, and achieve excellent thermal stability, slow photoreactive rate, and relatively high mobility of main chains

Inactive Publication Date: 2010-04-15
LG CHEM LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention relates to a photoreactive polymer that has an alignment property due to a photoreaction and includes a multi-cyclic compound in a main chain, which provides excellent thermal stability. The photoreactive polymer can be used as an alignment film for liquid crystal displays, and can quickly and easily achieve the desired alignment property. The technical effect of the invention is to improve the thermal stability of the alignment film while maintaining its alignment property, and to enhance the efficiency and quality of the production process of liquid crystal displays.

Problems solved by technology

In the use of the alignment film that is prepared by using the rubbing treatment method, there are problems in that the contamination is caused by the impurity that may be generated due to contact during the rubbing, the yield of the products is reclined due to the occurrence of static electricity, and contrast is reduced.
In the case of the method of inclinedly depositing silicon dioxide, there are problems in that the preparing cost is increased and it is difficult to form the film having a large area, thus, the film is not suitable to be applied to a large liquid crystal display.
However, the poly cinnamate-based polymer has a problem in that the optical alignment property of the polymer is excellent but the thermal stability is poor.
That is, the thermal stability of the alignment film depends on the thermal stability of the polymer, and since the main chain of the polymer of polyvinyl cinnamate has a glass transition temperature of 100° C. or less, there is a problem in that the thermal stability of the alignment film is reduced.
However, the patent is disadvantageous in that since the mobility of the polymer is poor, even though the polymer is exposed to light for a long time, it is difficult to obtain the desired alignment property.
The reason for this is that since the photo-sensitive group which is present in the polymer is restricted by the main chain of the polymer, the group is difficult to rapidly react with the radiated polarized light.
Accordingly, since a long time is required to obtain a network polymer, a process efficiency is reduced, and if an alignment treatment process is finished after an in-sufficient time, since the alignment of the liquid crystals is insufficient in the prepared liquid crystal display, there are problems in that a dichroic ratio is low and contrast is reduced.
However, as described in the above patent, in the case of when the polarized UV is radiated on a curable liquid crystal material to align the liquid crystal, since the curing of the liquid crystal maws in an alignment direction, the insufficient curing (pairs, thus reducing the surface strength and easily causing the deformation due to external impact or heat.

Method used

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Examples

Experimental program
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Effect test

example 1

Synthesis of 5-norbornene-2-methyl-4′-methoxy cinnamate ring-opened hydrogenated polymer

(1) Synthesis of 5-norbornene-2-methanol

[0099]DCPD (dicyclopentadiene, Aldrich, 397 g, 3 mol), and aryl alcohol (Aldrich, 331 g, 5.7 mol) were put into the high pressure reactor having the volume of 2 L and then heated to 210° C. The agitation was performed at 300 rpm to conduct the reaction for 1 hour. When the reaction was finished, the reactant was cooled and then moved to the distillation device. The distillation was performed twice under reduced pressure of 1 torr by using the vacuum pump to obtain the product at 56° C. (yield: 52%).

[0100]1H-NMR (300 MHz, CDCl3): δ6.17˜5.91 (m, 2H), 3.71˜3.19 (m, 2H), 2.91˜2.75 (m, 2H), 2.38 (m, 1H), 1.83 (m, 1H), 1.60˜1.12 (m, 2H), 0.52 (m, 1H)

(2) The Ring Opening Metathesis Polymerization and the Hydrogenation Reaction of 5-norbornene-2-methanol

[0101]6.20 g 150 mmol) of 5-norbornene-2-methanol that was synthesized in (1) was punt into the Schlenk flask ha...

example 2

Synthesis of the 5-norbornene-2-(4′-hydroxy-4-methoxychalcone)ester Ring-Opened Hydrogenated Polymer

(1) Synthesis of the Ring-Opened Hydrogenated Polymer of the 5-norbornene-2-carboxylic Acid

[0105]11.0 g (79.64 mmol) of the 5-norbornene-2-carboxylic acid was put into the Schlenk flask having the volume of 250 ml under an Ar atmosphere, and 55 g of toluene that was purified by using the solvent was added thereto. 18.2 mg (1.6 mmol) of triethyl aluminum (TEA) that was the cocatalyst was first added thereto while the flask was maintained at the polymerization temperature of 80° C. Subsequently, 1.6 ml of the 0.01 M (mol / L) toluene solution (WCl6 0.016 mmol, ethanol 0.048 mmol) in which tungsten hexachloride (WCl6) and ethanol were mixed with each other at a ratio in the range of 1:3 was added to the flask. Finally, 1.34 g of 1-octene (11.95 mmol) that was the molecular weight controlling agent was added to the flask and then reacted at 80° C. for 18 hours while the agitation was perfor...

example 3

Synthesis of the 5-norbornene-2-(7-hydroxy-6-methoxy coumarine)ester Ring-Opened Hydrogenated Polymer

[0108]10.1 g of the ring-opened hydrogenated polymer of the 5-norbornene-2-carboxylic acid that was synthesized in (1) of Example 2 (71.55 mmol), 12.49 g of 7-hydroxy-6-methoxycoumarin (Aldrich, 65.0 mmol), 19.9 g of EDC (N-ethyl-N′-(3-dimethylaminopropyl)carbodiimide hydrochloride) (Aldrich, 104.2 mmol), and 13.2 g of HOBT (1-Hydroxybenzotriazole hydrate) (Aldrich, 97.52 mmol) were sequentially put into the two-neck flask having the volume of 250 ml, and then dissolved in 100 ml of DMF. After the temperature was reduced to 0° C., triethylamine (Aldrich, 45 ml, 325 mmol) was slowly dropped. After the temperature was increased to normal temperature and maintained overnight. When the reaction was finished, the extraction was performed by using a great amount of ethyl acetate. The resulting substance was washed by using NaHCO3 and H2O, the reaction solution was dropped on acetone to per...

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Abstract

The present invention relates to a photoreactive polymer that comprises a multi-cyclic compound in a main chain, and a polymerization method thereof. Since the photoreactive polymer according to the present invention comprises a multi-cyclic compound having a high glass transition temperature as a main chain, the thermal stability is excellent, and since the mobility of the main chain is relatively high as compared to that of an additional polymer, a photoreactive group can be freely moved in the main chain of the polymer. Accordingly, it is possible to overcome a slow photoreactive rate that is considered a disadvantage of a polymer material used to prepare an alignment film for known liquid crystal display devices.

Description

TECHNICAL FIELD [0001]The present invention relates to a photoreactive polymer, and more particularly to a photoreactive polymer that has an alignment property due to a photoreaction and includes a multi-cyclic compound in a main chain, thus having the excellent thermal stability and allowing the photoreaction to be rapid.[0002]This application claims priority from Korea Patent Application Nos. 10-2007-0028114 and 10-2007-0028104 filed on Mar. 22, 2007 in the KIPO, the disclosure of which is incorporated herein by reference in its entirety.BACKGROUND ART [0003]In recent years, a liquid crystal display that has a light weight and consumes a small amount of electric power has been used as a most competitive display that can be used instead of a cathode ray tube. In particular, since a thin film transistor liquid crystal display (TFT-LCD) that is driven by using a thin film transistor independently drives each of pixels, a response speed of the liquid crystal is very high, thus, a high...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C08F4/44C08F4/00C08F4/06C08F24/00C08F18/02C07D311/02C07C69/00
CPCC08F210/02C08F290/00C08F290/14C08F297/00C08F297/06C08F232/00C08F2500/25C08F2500/26C08G61/00C08G61/02
Inventor CHOI, DAI-SEUNGJUNG, HYE-YOUNGCHUN, SUNG-HOKIM, HEONHONG, SUNG-DONYOO, DONG-WOO
Owner LG CHEM LTD
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