Siloxane Hard-Coating Resin Composition for Flexible Displays

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Solution Overview

Problem

Conventional hard-coating technologies for plastics face challenges in achieving a balance between high surface hardness and flexibility, with existing solutions either lacking in processability or resulting in decreased transmittance and dispersibility due to physical mixing of inorganic particles, which are not suitable for optical applications.

Innovation Solution

A siloxane resin composition with epoxy-siloxane molecules of varying molecular weights is chemically bonded, allowing for dense crosslinking during polymerization, providing high surface hardness while maintaining flexibility and processability, eliminating the need for physical mixing of inorganic particles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If inorganic particles are physically mixed with organic resin to improve surface hardness, then surface hardness is improved, but dispersibility and transmittance deteriorate

Engineering Contradiction:

Improvesurface hardnessVSAvoiddispersibility and transmittance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent uses organosiloxane molecules that contain both organic functional groups (for resin compatibility) and inorganic siloxane chains (for hardness). This molecular-level composite structure allows the inorganic component to be integrated within the organic matrix without physical mixing, achieving high surface hardness while maintaining excellent dispersibility and optical transmittance.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the molecular structure parameters by incorporating siloxane units with specific molecular weights (average 50-500) into the organic resin system. This parameter change transforms the material from a simple physical mixture to a molecularly dispersed composite, improving both hardness and optical properties simultaneously.

Inventive Principle:

Principle #35Parameter changes

2Strength

If conventional hard-coating resins are used to improve surface hardness, then surface hardness is improved, but flexibility deteriorates

Engineering Contradiction:

Improvesurface hardnessVSAvoidflexibility

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The patent controls the molecular weight of the siloxane units within a specific range (50-500) to optimize the balance between crosslinking density (for hardness) and chain flexibility. This parameter optimization allows the coating to achieve high surface hardness while maintaining the flexibility needed for flexible displays and wearable devices.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The organosiloxane molecules serve as a composite structure where the organic functional groups provide flexibility and processability while the inorganic siloxane chains provide hardness. This molecular composite approach resolves the contradiction between hardness and flexibility that plagues conventional hard-coating resins.

Inventive Principle:

Principle #40Composite materials

3Strength

If photo-radical polymerization of acrylate is used to achieve hard-coating, then surface hardness is improved, but processability deteriorates due to oxygen sensitivity

Engineering Contradiction:

Improvesurface hardnessVSAvoidprocessability

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent replaces photo-radical polymerization (which is sensitive to oxygen and requires inert atmospheres) with a different polymerization mechanism that proceeds in the presence of oxygen. This substitution eliminates the need for complex inert gas handling while still achieving high surface hardness through effective crosslinking.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The organosiloxane molecules act as intermediaries that enable crosslinking in the presence of oxygen. Their molecular structure allows them to react and form crosslinked networks without requiring the exclusion of oxygen, thereby simplifying the manufacturing process while maintaining coating hardness.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 siloxane resin composition achieves high surface hardness with excellent flexibility, making it suitable for various flexible devices and displays without compromising transmittance or dispersibility, thus addressing the limitations of conventional techniques.

Implementation Method 1

a siloxane resin consisting of epoxy-siloxane molecules with various molecular weights which leads to densely crosslinked networks

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Implementation Method 2

epoxy-siloxane molecules with various molecular weights which leads to densely crosslinked networks

Methodology Applied

Scientific EffectCrosslinking: Chemical Bonding

Data Source

PatentUS10858539B2Siloxane hard-coating resin composition

Publication Date: 2020.12.08 KOREA ADVANCED INST OF SCI & TECH

AI summary

The present disclosure provides a hard-coating resin composition for a hard-coating having easy processability, flexibility and high surface hardness suitable for a hard-coating agent, in which a siloxane molecule having an inorganic material characteristic is chemically bonded with an epoxy group having an organic material characteristic to form one molecule, and the siloxane molecule is made to contain a various molecular weight distribution for dense crosslinking during polymerization of the epoxy group in order to obtain high surface hardness due to the inorganic material.