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Cholesteric liquid crystal drying process and solvent

A cholesteric, solvent-based technology, applied in liquid crystal materials, chemical instruments and methods, etc., can solve problems such as high power consumption, low light transmittance or reflectivity, and reduced brightness of displays

Inactive Publication Date: 2011-12-21
3M INNOVATIVE PROPERTIES CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The low transmittance or reflectivity of these displays reduces the brightness of the display and may require high power consumption

Method used

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  • Cholesteric liquid crystal drying process and solvent
  • Cholesteric liquid crystal drying process and solvent
  • Cholesteric liquid crystal drying process and solvent

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0082] Comparison of Solubility of Various Monomers in 1,3-Dioxolane and Other Solvents 4-(2-Acryloyloxy-ethoxy)-benzoic acid 4′-cyano-biphenyl-4 The -yl ester is a cholesteric liquid crystal monomer having the following structure and can be prepared according to the method described in European Patent Application Publication No. 834754.

[0083]

[0084] Dissolve 4-(2-acryloyloxy-ethoxy)-benzoic acid 4′-cyano-biphenyl-4-yl ester in hot (boiling) THF and hot 1,3-dioxane in pentane. Only 20% of this monomer was soluble in tetrahydrofuran, while 40% of this monomer was soluble in 1,3-dioxolane. This indicates that the cholesteric liquid crystal monomer represented by 4-(2-acryloyloxy-ethoxy)-benzoic acid 4′-cyano-biphenyl-4-yl ester is in the 1,3-dioxane It is more soluble in pentane than in tetrahydrofuran.

Embodiment 2

[0086] Add another solvent to control drying temperature

[0087] Solution A was prepared by combining and dissolving the ingredients in Table 1.

[0088] compound weight percentage Cyanobiphenyl Benzoate Acrylate 30％ Paliocolor LC 756 (from BASF, Charlotte, NC, USA) 2.2％ carbon tetrabromide 0.25％ Azobisisobutyronitrile (Vazo) 52 (obtained from Wilmington, DE, USA) 0.83％ 1,3-dioxolane 66.7％

[0089] Solution A was purged with nitrogen and heated at about 60°C for about 18 hours to initiate acrylate polymerization. Solution A was then used to prepare Solutions B and C in Table 2 below.

[0090] components % by weight in solution B % by weight in solution C Solution A 50％ 50％ 4'-cyano-4-hydroxybiphenyl 5％ 5％ 1,3-dioxolane 32.5％ 45％ Cyclohexanone 12.5％ 0％

[0091] Solutions B and C were coated (approximately 12 to 15 μm wet coating thickness) onto a 10...

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Abstract

The invention provides methods of forming a cholesteric liquid crystal layer that include forming a cholesteric liquid crystal composition, depositing the cholesteric liquid crystal composition onto a substrate, and initially drying the cholesteric liquid crystal composition at a temperature at or below about 90 DEG C so that the cholesteric liquid crystal composition has at least 80 % solids remaining. The invention also provides methods of forming a cholesteric liquid crystal layer that include forming a cholesteric liquid crystal composition, depositing the cholesteric liquid crystal composition onto a substrate, and initially drying the cholesteric liquid crystal composition at a temperature at or below about 90 DEG C, wherein the drying is accomplished using a technique that provides little or no airflow. The invention further provides a cholesteric liquid crystal composition that includes at least one cholesteric liquid crystal precursor and 1,3-dioxolane.

Description

technical field [0001] This invention relates generally to cholesteric liquid crystal compositions for use in optical bodies such as reflective polarizers, and in particular to solvents used in those compositions and methods of drying the compositions to form optical bodies. Background technique [0002] Optical devices such as polarizers and reflectors are used in a variety of applications including liquid crystal displays (LCDs). Liquid crystal displays fall broadly into two categories: backlit (eg, transmissive) displays, in which light comes from behind the display panel, and front-lit (eg, reflective) displays, in which light comes from the front of the display (eg, ambient light). These two display modes can be combined to form a transflective display, which can be backlit, for example, in dim light conditions, or readable in bright ambient light. [0003] Conventional backlit LCDs typically use absorbing polarizers and can have less than 10% light transmission. Conv...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09K19/52
CPCC09K19/52C09K19/36C09K19/34
Inventor 史蒂文·D·所罗门松马克·D·拉德克利夫理查德·J·波克尔尼
Owner 3M INNOVATIVE PROPERTIES CO