Fluorene Polymer Urethane Bonds Color Filter Resolution

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Solution Overview

Problem

Conventional fluorene-based polymers used in color filter production have high acid value and low molecular weight, leading to poor development margin and chemical resistance, and are prone to pattern peeling due to unreacted acid dianhydride and low diol compound ratios.

Innovation Solution

A fluorene-based polymer with urethane bonds is developed by reacting an excess diol compound containing a fluorene moiety with a diisocyanate and then with an acid anhydride, increasing unsaturated double bonds and allowing control of acid value, thereby improving sensitivity and chemical resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the equivalent ratio between diol compound and acid dianhydride is close to 1:1 to improve development margin and chemical resistance, then development margin and chemical resistance are improved, but unreacted acid dianhydride remains which increases acid value and causes pattern peeling

Engineering Contradiction:

Improvedevelopment margin and chemical resistanceVSAvoidacid value increase and pattern peeling

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the equivalent ratio parameter from 1:1 to excess diol compound (greater than 1:1), and introduces urethane bond formation as a new reaction mechanism. This allows complete reaction of acid dianhydride while maintaining good development margin and chemical resistance, eliminating the harmful effects of unreacted acid dianhydride.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces diisocyanate as an intermediary substance that reacts with both the diol compound and acid dianhydride. This intermediary enables the formation of urethane bonds, allowing the acid dianhydride to react completely without compromising the development margin and chemical resistance properties.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Quantity of substance

If diol compound is used in larger amount than acid dianhydride to decrease molecular weight and acid value, then molecular weight and acid value decrease, but development margin and chemical resistance deteriorate

Engineering Contradiction:

Improvemolecular weight and acid valueVSAvoiddevelopment margin and chemical resistance

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent uses diisocyanate as an intermediary that reacts with excess diol compound to form urethane bonds. This intermediary mechanism allows the use of excess diol compound (increasing quantity) while maintaining good development margin and chemical resistance through the urethane bond formation, resolving the contradiction between quantity and reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Strength

If conventional fluorene-based polymer is used to maintain good substrate adhesion, then substrate adhesion is maintained, but the polymer is vulnerable to development due to high acid value and low molecular weight

Engineering Contradiction:

Improvesubstrate adhesionVSAvoiddevelopment margin and chemical resistance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent creates a composite polymer structure by introducing urethane bonds into the fluorene-based polymer chain. This composite structure combines the substrate adhesion properties of fluorene-based polymers with the improved development margin and chemical resistance provided by the urethane bond configuration, resolving the contradiction between adhesion strength and development reliability.

Inventive Principle:

Principle #40Composite materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The resulting polymer exhibits improved development margin, chemical resistance, and high sensitivity while maintaining good substrate adhesion, with controlled acid value and increased molecular weight, enhancing the production of color filters.

Implementation Method 1

reacting an excess diol compound containing a fluorene moiety with a diisocyanate and then with an acid anhydride

Methodology Applied

Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

negative-type photosensitive resin composition comprising the fluorene-based polymer to achieve good development margin, improved chemical resistance and high sensitivity

Methodology Applied

Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentUS8535874B2Fluorene-based polymer containing urethane groups, preparation method thereof and negative-type photosensitive resin composition comprising the same

Publication Date: 2013.09.17 LG CHEM LTD

AI summary

Provided is a novel fluorene-based polymer having urethane bonds and a method for preparing the fluorene-based polymer. According to the method, a diol compound is condensed with a diisocyanate instead of an acid dianhydride, and then an acid anhydride is reacted with the reaction mixture to introduce desired acid groups into the final polymer. Further provided is a negative-type photosensitive resin composition comprising of the fluorene-based polymer as a binder resin. The composition exhibits improved chemical resistance, good development margin and high sensitivity due to presence of the acid groups despite the low molecular weight of the fluorene-based polymer.