Optical Pressure-Sensitive Adhesive Composition for Water-Peelable Bonding

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Solution Overview

Problem

Pressure-sensitive adhesives (PSAs) face a trade-off between adhesive strength and reworkability, particularly in optical applications where fragile or thin adherends require reduced peel strength to prevent damage during reworking, and must also maintain optical properties like transparency.

Innovation Solution

A PSA composition comprising an acrylic polymer with limited alkoxyalkyl (meth)acrylate and alkoxypolyalkylene glycol (meth)acrylate content, combined with surfactants or polyoxyalkylene backbone-containing compounds, allows for good adhesive strength and water-peeling properties, enabling easy reworkability while maintaining transparency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If adhesive strength is improved, then bonding reliability is improved, but reworkability deteriorates

Engineering Contradiction:

Improveadhesive strengthVSAvoidreworkability

Core Design Contradiction:

ReliabilityVSEase of repair

Solution Approach 1:

The patent changes the chemical composition parameters of the PSA by limiting the content of alkoxyalkyl (meth)acrylate and alkoxypolyalkylene glycol (meth)acrylate to less than 20% each, while maintaining other components. This parameter adjustment allows the PSA to achieve both high adhesive strength and water-peeling properties, resolving the contradiction between bonding reliability and reworkability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces water as an intermediary substance to enable reworkability. By incorporating surfactants or polyoxyalkylene backbone-containing compounds that promote water-peeling, the PSA allows water to act as a mediator for easy separation during rework without compromising the initial adhesive strength. This intermediary approach enables both strong bonding and easy rework.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of repair

If peel strength is reduced to prevent damage during reworking, then reworkability is improved, but adhesive strength deteriorates

Engineering Contradiction:

ImprovereworkabilityVSAvoidadhesive strength

Core Design Contradiction:

Ease of repairVSStrength

Solution Approach 1:

The patent adjusts the compositional parameters by restricting alkoxyalkyl (meth)acrylate and alkoxypolyalkylene glycol (meth)acrylate content to less than 20% each, which changes the balance between cohesive and adhesive properties. This parameter change enables the PSA to maintain sufficient adhesive strength while achieving water-peeling properties for easy rework without damaging the adherend.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite PSA formulation combining acrylic polymer with specific limitations on alkoxyalkyl and alkoxypolyalkylene glycol (meth)acrylate content, along with surfactants or polyoxyalkylene backbone-containing compounds. This composite material structure achieves both high adhesive strength and water-peeling properties, resolving the contradiction between bond strength and reworkability.

Inventive Principle:

Principle #40Composite materials

3Illumination intensity

If transparency is maintained for optical applications, then optical properties are preserved, but adhesive strength may be compromised

Engineering Contradiction:

ImprovetransparencyVSAvoidadhesive strength

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters by limiting alkoxyalkyl (meth)acrylate and alkoxypolyalkylene glycol (meth)acrylate to less than 20% each, which maintains the optical transparency of the PSA while ensuring sufficient adhesive strength through the controlled composition of other components.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent develops a composite PSA material specifically tailored for optical applications, combining acrylic polymer with controlled amounts of alkoxyalkyl and alkoxypolyalkylene glycol (meth)acrylate, along with surfactants or polyoxyalkylene backbone-containing compounds. This composite formulation maintains transparency while achieving reliable adhesive strength suitable for optical members.

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 PSA composition achieves a balance of high adhesive strength and reworkability, allowing for effective peeling with water without compromising optical properties, ensuring reliable bonding and ease of reapplication on optical members.

Implementation Method 1

the PSA composition further comprises at least one species of compound A selected among surfactants and compounds having polyoxyalkylene backbones

Methodology Applied

Scientific EffectSurfactant: Surfactant

Data Source

PatentUS11795350B2Optical pressure-sensitive adhesive composition and use thereof

Publication Date: 2023.10.24 NITTO DENKO CORP

AI summary

Provided is an optical PSA composition that can be easily peeled using an aqueous liquid such as water and has sufficient adhesive strength. An optical PSA composition comprising an acrylic polymer is provided. The PSA composition comprises at least one species of compound A selected among surfactants and compounds having polyoxyalkylene backbones. The monomers forming the acrylic polymer comprises less than 20 wt % alkoxyalkyl (meth)acrylate and less than 20 wt % alkoxypolyalkylene glycol (meth)acrylate. Alternatively, the compound A content is less than 1 part by weight to 100 parts by weight of the acrylic polymer.