Water-Based Conductive Ink for High-Speed RFID Antennas
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current electrically conductive inks face challenges such as high electrical resistivity, long drying and curing times, and incompatibility with low-cost substrates like paper and cardboard due to high thermal requirements, which limit their use in high-speed printing applications for electronic circuitry and RFID antennas.
Innovation Solution
A water-based conductive ink composition using a styrene-acrylic copolymer matrix with anionic wetting agents to disperse silver particles, achieving high conductivity and low sheet resistance, suitable for high-speed printing on low-cost substrates with reduced thermal energy requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solvent-based thick film systems are used to achieve high conductivity, then electrical resistivity is reduced, but drying and curing time increases and thermal energy consumption increases
Solution Approach 1:
The patent changes the fundamental parameter of the solvent system from organic solvent to water, enabling rapid evaporation at ambient or low temperatures. This parameter change allows the ink to achieve high conductivity without requiring long drying times or high thermal energy input, as water can evaporate quickly under mild conditions compared to organic solvents
Solution Approach 2:
The patent replaces the thermal curing mechanism with a water-based evaporation mechanism. Instead of relying on high-temperature thermal processes to dry and cure the ink, the system uses the evaporative properties of water to achieve rapid drying at ambient or low temperatures, substituting a thermal field with a phase-change process
2Reliability
If high drying temperatures are used to achieve proper ink curing, then conductivity is improved, but substrate compatibility deteriorates for low-cost substrates
Solution Approach 1:
The patent changes the drying temperature parameter from high temperature to ambient or low temperature by using water as the solvent. Water's low boiling point and high vapor pressure at room temperature enable the ink to dry and cure properly without exposing substrates to high thermal stresses, thereby expanding compatibility to include paper, cardboard, and low-melting-point plastics
Solution Approach 2:
The patent uses water as an intermediary carrier that mediates between the conductive particles and the substrate. Water provides a benign drying environment that protects temperature-sensitive substrates while still enabling proper ink curing, acting as a protective intermediary that allows the use of low-cost substrates without compromising electrical performance
3Reliability
If conductive powder concentration is increased to achieve high conductivity, then electrical resistivity is reduced, but manufacturing cost increases
Solution Approach 1:
The patent changes the particle distribution parameter by using water as a dispersing medium. Water provides excellent wetting and dispersing properties for conductive particles, allowing them to be evenly distributed at lower concentrations while still achieving high conductivity. This reduces the amount of expensive conductive powder needed compared to organic solvent-based systems
4Object-affected harmful factors
If water-based ink is used to reduce environmental impact, then ecological advantage is improved, but electrical conductivity deteriorates compared to solvent-based systems
Solution Approach 1:
The patent changes multiple parameters simultaneously: the solvent composition (water-based), particle size distribution, and particle concentration. These parameter changes work together to achieve high conductivity in a water-based system, overcoming the traditional limitation that water-based inks have poor conductivity. The specific parameter组合 allows the ink to maintain high conductivity while being environmentally friendly
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 ink provides a UHF RFID antenna read range of at least 3 meters with a sheet resistance of less than 120 milliohm/square, maintaining print resolution and substrate adhesion, while being environmentally friendly and cost-effective.
Implementation Method 1
a water soluble copolymer of styrene and (meth)acrylic acid or a salt thereof, and an anionic wetting agent, which synergistically disperses the conductive particles
Implementation Method 2
aqueous conductive inks... offer significant ecological advantages over solvent-based compositions, as the latter release solvents into the atmosphere on drying
Data Source
AI summary
Disclosed is a conductive composition which can be used to form an aqueous conductive ink with increased conductivity. A film of the dry ink having a thickness of 5 microns or less has a surface roughness of less than 1.5 times the surface roughness of a cellulosic-based substrate which it coats. The aqueous conductive composition contains conductive particles, preferably silver, an anionic wetting agent and a styrene-acrylic copolymer. The composition is highly conductive and requires reduced drying energy. In addition, it may be applied to low cost substrates by high speed printing processes.