UV Curable Polycarbonate Inks for Thermoformed Electronics
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Solution Overview
Problem
Current technologies lack UV curable conductive inks with high elongation and low sheet resistance, as well as UV curable dielectric inks with high migration resistance, which are essential for thermoformed printed electronic applications and injection molding processes.
Innovation Solution
The development of UV curable conductive and dielectric ink compositions that include a binder medium comprising polycarbonate resin, acrylated polymers or oligomers with a polycarbonate backbone, ethylenically unsaturated monomers or oligomers without a polycarbonate backbone, photoinitiators, and group IV metal adhesion promoters, such as organo titanium adhesion promoters, to achieve high elongation, excellent adhesion, and good ink continuity during and after thermoform processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional UV curable inks are used on polycarbonate substrates, then adhesion can be achieved, but elongation rate matches the substrate and maintains contact during heating and molding
Solution Approach 1:
The ink composition uses a composite resin system combining polycarbonate resin with acrylated polymers or oligomers having a polycarbonate backbone, along with ethylenically unsaturated monomers or oligomers. This composite formulation enables the cured ink to simultaneously achieve strong adhesion to the polycarbonate substrate and match the substrate's elongation rate during thermoforming, resolving the contradiction between adhesion strength and adaptability to deformation.
Solution Approach 2:
The invention modifies the chemical composition parameters of the ink by incorporating specific ratios of polycarbonate resin (0.5-20 wt%), acrylated polymers/oligomers with polycarbonate backbone (2-50 wt%), and ethylenically unsaturated monomers/oligomers without polycarbonate backbone (5-60 wt%). These parameter changes enable the cured ink to achieve both strong adhesion and high elongation capability that matches the substrate during thermoforming processing.
2Strength
If inerts or passive resins are added to improve adhesion, then adhesion is enhanced, but resistance to injection of backfill resin decreases
Solution Approach 1:
The invention changes the chemical nature of the resin components by using reactive polycarbonate-based acrylated polymers or oligomers instead of inert or passive resins. This parameter change maintains strong adhesion while providing resistance to injection of backfill resin, as the reactive polycarbonate backbone forms a chemically bonded network that is resistant to solvent attack during injection molding.
Solution Approach 2:
The invention replaces expensive inert resins that provide temporary adhesion with a cost-effective reactive polycarbonate-based system that provides both adhesion and long-term resistance to injection. The reactive components form permanent chemical bonds that withstand the injection molding process without requiring additional protective measures.
3Reliability
If UV curable conductive inks are developed for thermoforming, then conductive functionality is achieved, but high elongation and low sheet resistance are difficult to obtain
Solution Approach 1:
The conductive ink uses a composite formulation combining the polycarbonate-based binder system with conductive particles. The binder provides the matrix that enables high elongation through its polycarbonate backbone structure, while the conductive particles dispersed within provide low sheet resistance. This composite approach simultaneously achieves conductive functionality, high elongation, and low sheet resistance without requiring separate layers or complex structures.
4Reliability
If UV curable dielectric inks are developed for thermoforming, then dielectric functionality is achieved, but high migration resistance is difficult to obtain
Solution Approach 1:
The dielectric ink uses a composite formulation with the polycarbonate-based binder system that provides a chemically resistant matrix. The reactive polycarbonate backbone and crosslinked network structure create a dense, chemically bonded framework that prevents ion migration and electrochemical degradation. This composite structure simultaneously achieves dielectric functionality and high migration resistance without requiring additional barrier layers or complex protective structures.
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 resulting ink compositions exhibit high elongation and thermoformability, maintaining excellent properties during injection molding processes, and demonstrate good sheet resistance, electrical resistivity, volume resistivity, and dielectric breakdown voltage, while also showing resistance to electrochemical silver migration.
Implementation Method 1
UV curable conductive and dielectric inks... comprising a binder medium comprising polycarbonate resin, acrylated polymers or oligomers with a polycarbonate backbone, ethylenically unsaturated monomers or oligomers without a polycarbonate backbone, photoinitiators
Implementation Method 2
group IV metal adhesion promoters, such as organo titanium adhesion promoters, to achieve high elongation, excellent adhesion
Implementation Method 3
substrate... is heated to the substrate's softening point and stretched... inks to have a similar elongation rate as the substrate
Implementation Method 4
inks... exhibit high elongation... maintaining excellent properties during injection molding processes
Data Source
AI summary
UV curable inks comprising a polycarbonate resin; acrylated polymers or oligomers having an aromatic or aliphatic polycarbonate backbone, one or more photoinitiators; and one or more adhesion promoters, are provided, which inks can be formulated as conductive inks or dielectric inks. The UV-curable inks are useful in preparing printed electronic and injection-molded structural electronic components and devices. The UV-curable inks exhibit high elongation and thermoformability, and are especially well suited for use in injection molding processes for printed electronics and thermoformed printed electronic applications.