Thiol-Based OCA Resin Composition for Pretreatment-Free Adhesion

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Solution Overview

Problem

Current polyacrylate-based optically clear adhesives face challenges in achieving high adhesion levels without substrate pretreatment and maintaining optical and thermomechanical properties under extreme weathering conditions, particularly in flexible display technologies.

Innovation Solution

A polymeric resin composition comprising thiol monomers, vinyl or allyl monomers, difunctional aliphatic urethane oligomers, and additives like hydrolytic stabilizers, photoinitiators, and cyclic azasilane monomers, cured using UVA light, forms adhesives with enhanced adhesion and stability, utilizing amine-epoxide-based chemistry to achieve >1100 gf/in adhesion without pretreatment and maintaining optical clarity and mechanical performance under high humidity and temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If polyacrylate-based OCAs are used, then optical transparency is achieved, but adhesion level and network stability under extreme weathering conditions deteriorate

Engineering Contradiction:

Improveadhesion levelVSAvoidnetwork stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical composition parameters by incorporating thiol monomers (30-60 wt%), vinyl or allyl monomers (20-60 wt%), and difunctional aliphatic urethane oligomers (10-30 wt%) to create a resin composition that achieves both high adhesion (>1000 gf/in) and network stability under extreme weathering conditions, resolving the contradiction between adhesion and stability in polyacrylate-based OCAs

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite resin composition combining multiple monomer types (thiol, vinyl, allyl) and oligomers with specific functional groups that work synergistically to provide both high adhesion forces and long-term network stability under heat, humidity, and UV exposure, overcoming the limitations of single-component polyacrylate systems

Inventive Principle:

Principle #40Composite materials

2Strength

If thiol-click-based OCAs are used, then storage modulus and mechanical performance are improved, but adhesion level without substrate pretreatment deteriorates

Engineering Contradiction:

Improvestorage modulusVSAvoidadhesion level

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent introduces cyclic azasilane monomers (0.1-1 wt%) and hydrolytic stabilizers (1-3 wt%) as intermediary components that facilitate strong bonding between the thiol-click adhesive network and substrate surfaces without requiring pretreatment, enabling both low storage modulus (0.2 MPa or less) and high adhesion levels (>1000 gf/in) simultaneously

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies local quality enhancement by incorporating specific functional groups (azasilane, hydrolytic stabilizer) at targeted concentrations (0.1-1 wt% and 1-3 wt% respectively) to create localized bonding sites that provide high adhesion forces at the interface while maintaining the overall mechanical properties of the adhesive layer

Inventive Principle:

Principle #3Local quality

3Stability of the object's composition

If OCAs are exposed to extreme weathering conditions, then optical clarity is maintained, but yellowing and haze increase

Engineering Contradiction:

Improveoptical clarityVSAvoidyellowing and haze

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent converts the potentially harmful effect of UV exposure and heat into beneficial outcomes by incorporating UV stabilizers and hydrolytic stabilizers that prevent photodegradation and hydrolysis, transforming the adhesive into a system where extreme weathering conditions actually enhance long-term optical stability and prevent yellowing and haze

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 adhesive achieves high adhesion to substrates without pretreatment, maintains optical clarity with low haze and yellowing, and retains mechanical stability under extreme conditions, supporting flexible display technologies.

Implementation Method 1

The polymeric resin composition is cured into a film using UVA light

Methodology Applied

Scientific EffectPhotopolymerisation: Photopolymerisation

Implementation Method 2

The process comprises a tandem ring-opening mechanism that forms covalent bonds between the OCA and the substrate

Methodology Applied

Scientific EffectChemical Bonding: Chemical Bonding

Data Source

PatentUS20250313736A1Resin compositions for optically clear adhesives and methods of enhancing adhesion forces thereof

Publication Date: 2025.10.09 ARES MATERIALS INC

AI summary

An optically clear adhesive (OCA) includes a polymeric resin composition. The polymeric resin composition includes 30 to 60 wt % of a thiol monomer, 20 to 60 wt % of at least one of a vinyl monomer or an allyl monomer, and 10 to 30 wt % of a difunctional aliphatic urethane oligomer. The polymeric resin composition further includes 1 to 3 wt % of a hydrolytic stabilizer additive, 1 to 5 wt % of a glycidyl monomer having at least one of an allyl functional group or an acrylate functional group, 0.1 to 1 wt % of a cyclic azasilane monomer, 0.5 to 2 wt % of a photoinitiator, and 0.01 to 0.03 wt % of a wetting additive. A method for enhancing adhesion forces of optically clear adhesives is also disclosed.