Epoxy Acrylate Adhesive Composition for Tack Without Premature Curing
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Solution Overview
Problem
Existing adhesive compositions face challenges in achieving a balance between initial tack and peel adhesion while maintaining stability and compatibility with various substrates, particularly when used in applications requiring high glass transition temperatures and avoiding premature curing due to acidic or nitrogen-containing monomers.
Innovation Solution
A composition comprising 30-50 wt.% epoxy resin and 20-50 wt.% of (meth)acrylic polymer with specific monofunctional (meth)acrylate monomers, including low Tg monomers and non-acidic polar monomers, which are polymerized to form a compatible single phase or interpenetrating polymer network, enhancing adhesion and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If acidic or nitrogen-containing monomers are used to improve adhesion, then adhesion strength is improved, but premature curing and corrosion occur
Solution Approach 1:
The patent removes acidic and nitrogen-containing monomers from the adhesive composition to eliminate the harmful effects of premature curing and corrosion. Instead, it uses non-acidic polar monomers that provide adhesion without the detrimental side effects, effectively extracting the problematic components while retaining the beneficial adhesion property.
Solution Approach 2:
The patent introduces non-acidic polar monomers as intermediary substances that mediate between the substrate and the epoxy resin. These monomers provide the necessary polarity for strong adhesion to substrates like metals without triggering premature curing or causing corrosion, serving as a safe intermediary that achieves adhesion without the harmful effects of traditional acidic monomers.
2Temperature
If high Tg monomers are used to achieve high glass transition temperature, then thermal stability is improved, but initial tack and peel adhesion decrease
Solution Approach 1:
The patent applies local quality by using a combination of low Tg monomers (providing initial tack and flexibility) and high Tg monomers (providing thermal stability). Different regions of the adhesive composition have different Tg characteristics, with the low Tg monomers dominating the initial adhesion properties and the high Tg monomers contributing to the final cured network's thermal stability.
Solution Approach 2:
The patent creates a composite adhesive system combining monomers with different Tg characteristics. The low Tg monomers (such as butyl acrylate) provide initial tack and flexibility, while the high Tg monomers (such as cycloaliphatic monomers) contribute to thermal stability. This composite approach allows the adhesive to exhibit both good initial adhesion and high thermal stability in the cured state.
3Strength
If epoxy resin content is increased to improve adhesion and stability, then adhesion strength is improved, but viscosity increases and processing becomes difficult
Solution Approach 1:
The patent optimizes the epoxy resin content parameter to a specific range (30-50 wt.%) that balances adhesion strength and processability. By carefully controlling this parameter and combining it with specific monomer selections, the patent achieves high adhesion without excessive viscosity, making the adhesive easier to process and apply while maintaining strong bonding performance.
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 composition achieves improved initial tack and peel adhesion with stable phase separation and compatibility, suitable for a wide range of substrates, including metals, while minimizing premature curing and corrosion.
Implementation Method 1
comprising polymerized units of monofunctional (meth)acrylate monomers
Data Source
AI summary
Adhesive compositions are described comprises 30-50 wt. % of an epoxy resin component; and 20 to 50 wt. % of (e.g. (meth)acrylic polymer comprising polymerized units of) monofunctional (meth)acrylate monomers comprising i) low Tg (meth)acrylate monomer(s) wherein a homopolymer thereof has a glass transition temperature (Tg) of less than 0° C. in an amount of at least 20 wt. %; and ii) non-acidic polar (meth)acrylate monomer(s) in an amount of at least 20 wt. %; wherein the amount of monomers is based on the total amount of monofunctional (meth)acrylate monomers. Also described are methods of bonding and articles.