Oxetane-Epoxy Composite Sheet for Flexible Display Substrates

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Solution Overview

Problem

Existing composite sheets for display substrates face challenges with low heat resistance, flexibility, and processibility due to high glass transition temperatures, which affect their suitability for flexible substrates and manufacturing processes.

Innovation Solution

A composite sheet using an oxetane-epoxy bifunctional compound as a binder, combined with glass fillers, which maintains flexibility and transparency while increasing heat resistance and processibility, and allows for adjustable curing rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If glass fiber cloths with epoxy resins are used to increase heat resistance, then the glass transition temperature increases, but the composite sheet becomes rigid and loses flexibility

Engineering Contradiction:

Improveglass transition temperatureVSAvoidflexibility

Core Design Contradiction:

TemperatureVSEase of operation

Solution Approach 1:

The patent changes the chemical parameters of the epoxy resin by selecting specific types (E-61, E-51, or E-44) and controlling their molecular weight and structure. This allows achieving high glass transition temperature (145-160°C) while maintaining flexibility through proper molecular design and selection of resin types with appropriate chain mobility

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system combining epoxy resin with specific glass fiber cloths (J77, J83, or J91) in optimized ratios. The composite structure allows the resin matrix to provide heat resistance while the fiber-reinforced structure maintains mechanical flexibility and bendability

Inventive Principle:

Principle #40Composite materials

2Temperature

If the glass transition temperature is increased to improve heat resistance, then the composite sheet becomes brittle and solubility decreases

Engineering Contradiction:

Improveheat resistanceVSAvoidbrittleness

Core Design Contradiction:

TemperatureVSStrength

Solution Approach 1:

The patent optimizes the chemical parameters of the epoxy resin system by selecting specific resin types (E-61, E-51, E-44) with different molecular weights and structures. This allows achieving high heat resistance while maintaining adequate solubility and preventing brittleness through proper molecular design

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies different properties to different components: the epoxy resin provides heat resistance and binding, while the glass fiber cloths provide structural strength and flexibility. This local differentiation of functions allows the composite to achieve heat resistance without becoming uniformly brittle

Inventive Principle:

Principle #3Local quality

3Stability of the object's composition

If polyimide resin is used to reduce coefficient of thermal expansion, then thermal expansion improves, but transparency decreases and moisture absorption increases

Engineering Contradiction:

Improvecoefficient of thermal expansionVSAvoidtransparency

Core Design Contradiction:

Stability of the object's compositionVSIllumination intensity

Solution Approach 1:

The patent extracts the beneficial property (low coefficient of thermal expansion) from polyimide resin while avoiding its harmful properties (poor transparency and high moisture absorption) by selecting alternative epoxy resin types (E-61, E-51, E-44) that inherently provide better optical properties and moisture resistance while maintaining thermal stability through proper formulation

Inventive Principle:

Principle #2Taking out (Extraction)

4Ease of manufacture

If conventional epoxy resins are used in composite sheets, then manufacturing is simplified, but the glass transition temperature is too low for high-temperature processing

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidglass transition temperature

Core Design Contradiction:

Ease of manufactureVSTemperature

Solution Approach 1:

The patent changes the chemical parameters of the epoxy resin by selecting specific types (E-61, E-51, or E-44) and controlling their molecular weight, structure, and cross-linking density. This allows achieving high glass transition temperature (145-160°C) suitable for high-temperature processing while maintaining ease of manufacture through conventional epoxy resin processing methods

Inventive Principle:

Principle #35Parameter changes

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 composite sheet achieves excellent heat resistance, flexibility, and processibility, with a low coefficient of thermal expansion and high light transmittance, enabling the production of lightweight, cost-effective display substrates.

Implementation Method 1

a composite sheet, which includes an oxetane-epoxy compound having a specific structure as a binder

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

a low coefficient of thermal expansion

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS9034971B2Composite sheet and display substrate using same

Publication Date: 2015.05.19 SAMSUNG SDI CO LTD

AI summary

A composite sheet of the present invention comprises an oxetane-epoxy-based compound, represented by chemical formula 1, as a binder.