Epoxy-Acid Crosslinkable Pressure-Sensitive Adhesive
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-performance pressure-sensitive adhesives (PSAs) require improved shear holding capability at elevated temperatures while maintaining tack and adhesion, but existing crosslinking agents like chlorinated triazines are undesirable due to corrosive by-products and color issues, especially in electronics and medical applications.
Innovation Solution
A crosslinkable composition comprising an epoxy-functional (meth)acrylic copolymer with interpolymerized epoxy and acid-functional monomers, which can crosslink without an ionic photoacid generator, providing a balance of tack, peel adhesion, and shear holding power, and is suitable for high-temperature applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If chlorinated triazine crosslinkers are used to improve shear holding capability, then high-temperature performance is improved, but corrosive by-products and undesirable color are generated
Solution Approach 1:
The patent converts the harmful chlorinated triazine crosslinking system into a beneficial alternative by using epoxy-functional and acid-functional monomers that crosslink through safe, non-corrosive mechanisms. The epoxy groups react with acid groups to form stable crosslinks without generating harmful by-products, thus converting the harmful chemical pathway into a beneficial one that maintains shear strength while eliminating corrosion and color issues.
Solution Approach 2:
The patent changes the chemical parameters of the crosslinking system by replacing chlorinated triazines with epoxy-functional and acid-functional monomers. This parameter change includes using different functional groups (epoxy and acid instead of chlorinated triazine) and different crosslinking mechanisms (acid-catalyzed ring-opening polymerization instead of conventional crosslinking), which fundamentally alters the reaction pathway to eliminate harmful by-products while maintaining high-temperature shear holding capability.
2Strength
If crosslinking is used to improve shear holding capability, then high-temperature performance is improved, but tack and adhesion may be compromised
Solution Approach 1:
The patent applies local quality by creating different functional zones within the adhesive composition. The epoxy-functional and acid-functional monomers are incorporated at specific concentrations (0.1-10 wt% and 0.1-5 wt% respectively) to provide localized crosslinking density that enhances shear holding while maintaining sufficient tack and adhesion in other regions. This controlled local crosslinking ensures high-temperature performance without compromising the overall balance of adhesive properties.
Solution Approach 2:
The patent creates a composite adhesive system by combining multiple components: base polymer, epoxy-functional monomer, acid-functional monomer, and optional catalyst. This composite approach allows the different components to work synergistically - the base polymer provides tack and adhesion, while the epoxy and acid functional monomers provide crosslinking for shear strength, achieving a balance of properties that neither component could provide alone.
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 solution achieves high shear holding capability at elevated temperatures without compromising tack and adhesion, and eliminates the drawbacks of chlorinated triazine crosslinkers, such as corrosive by-products and undesirable color, making it suitable for diverse applications including electronics.
Implementation Method 1
the epoxy and acid groups of the copolymer can crosslink
Implementation Method 2
polymers designed and formulated to exhibit the requisite viscoelastic properties resulting in a desired balance of tack, peel adhesion, and shear holding power
Data Source
AI summary
A pre-adhesive composition is described comprising an acid- and epoxy-functional (meth)acryloyl copolymer, which when crosslinked with or without using an ionic photoacid generator (PAG) provides a pressure-sensitive adhesive and pressure-sensitive adhesive articles having desirable properties.