UV-Curable Interlayer for Adhesion-Conductivity Trade-off
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Solution Overview
Problem
The challenge in fabricating electronic circuit elements using metal nanoparticle inks, such as silver nanoparticle inks, lies in the trade-off between electrical conductivity and adhesion to the substrate, where highly conductive layers often have poor adhesion, making them prone to damage and limiting their functionality.
Innovation Solution
The development of UV-curable interlayer compositions and multilayer structures that include a substrate, an interlayer film formed from a UV-curable composition comprising aliphatic di(meth)acrylate monomers, (meth)acrylate oligomers, and photoinitiators, which provide excellent adhesion and conductivity while allowing for curing at lower temperatures and times, compatible with processing techniques like ink jet printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermally curable interlayer compositions are used to improve adhesion, then adhesion is improved, but curing temperature and time increase
Solution Approach 1:
The patent replaces thermal curing mechanisms with UV photopolymerization. The interlayer composition contains photopolymerizable functional groups that undergo crosslinking upon UV irradiation, eliminating the need for high-temperature thermal curing while achieving equivalent or superior adhesion to conductive nanoparticle layers.
Solution Approach 2:
The patent changes the curing mechanism from thermal to photopolymerizable by incorporating specific photopolymerizable functional groups into the interlayer composition. This parameter change enables curing at ambient temperatures under UV light, dramatically reducing curing time and temperature requirements while maintaining adhesion performance.
2Strength
If thermally curable interlayer compositions are used to improve adhesion, then adhesion is improved, but curing time increases
Solution Approach 1:
The patent replaces slow thermal curing with rapid UV photopolymerization. The photopolymerizable functional groups in the interlayer composition undergo instantaneous crosslinking upon UV irradiation, reducing curing time from hours to minutes while maintaining strong adhesion to conductive nanoparticle layers.
Solution Approach 2:
The patent changes the curing kinetics from thermal diffusion-controlled to photo-initiated radical polymerization. This parameter change enables rapid curing at ambient temperature under UV light, dramatically reducing the time required to achieve adequate adhesion compared to thermal curing methods.
3Reliability
If metal nanoparticle inks are used to achieve high conductivity, then electrical conductivity is improved, but adhesion to substrate deteriorates
Solution Approach 1:
The patent introduces a UV-curable interlayer composition as an intermediary between the substrate and conductive nanoparticle layer. This interlayer contains photopolymerizable functional groups that form a bonded interface with both the substrate and the metal nanoparticles, simultaneously achieving good adhesion to the substrate and maintaining the electrical conductivity of the nanoparticle layer.
Solution Approach 2:
The patent uses a composite interlayer composition combining photopolymerizable functional groups with appropriate binders and additives. This composite material provides both mechanical adhesion to the substrate and chemical compatibility with metal nanoparticles, enabling the conductive layer to maintain both conductivity and adhesion properties.
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
This solution enables efficient production of interlayer films that provide excellent adhesion and mechanical robustness to conductive layers, maintaining conductivity and reducing the risk of damage, while allowing for faster and lower-temperature curing compared to thermally curable interlayers.
Implementation Method 1
at least two photoinitiators
Implementation Method 2
The interlayer composition comprises at least one aliphatic di(meth)acrylate monomer diluent, at least one (meth)acrylate oligomer, and at least two photoinitiators
Data Source
AI summary
UV-curable interlayer compositions are provided. In embodiments, the interlayer composition comprises at least one aliphatic di(meth)acrylate monomer diluent having a dynamic viscosity at 25° C. of less than about 100 cps; at least one (meth)acrylate oligomer selected from epoxy (meth)acrylates, polyester (meth)acrylates, polyether (meth)acrylates, urethane (meth)acrylates and combinations thereof, the at least one (meth) acrylate oligomer having a glass transition temperature in the range of from about minus 10° C. to about 100° C. and a dynamic viscosity at 25° C. of less than about 3000 cps; and at least two photoinitiators. Multilayer structures formed using the compositions and related methods are also provided.