Print Treatments to Enable Unique Substrates for Printed Electronics

Many everyday products contain mass produced printed electronic components. Each mass-produced printed component is a replicate of the last, making their manufacture well suited for “analog” print manufacturing, such as flexography. The use of ultra-high-resolution flexographic printing enables very small individual features and fine increments in size that enhance the ability to create patterns with very complex shapes. These benefits, among others, enable improved form, fit, and function for the user of products manufactured using this technique.
Market applications for many printed electronic products require the use of substrates with specific properties. Substrates such as cyclic olefin polymer (COP), cyclic olefin copolymer (COC), polycarbonate (PC)and polymethylmethacrylate (PMMA) offer thermal and optical properties for printed electronics applications that cannot be achieved with polyethylene terephthalate (PET). In other cases, inks for printed electronics require curing conditions that PET cannot withstand, but others, such as polyethylene naphthalate (PEN) can. Many of these materials are not typically compatible with printing inks and other subsequent processes such as wire bonding or electroless plating. Surface treatments can be employed to enable manufacturability on difficult substrates – either by the substrate supplier or during the printing process.
Surface treatments can include corona treatment or plasma treatment alone or in combination with coatable or printable compositions. Coatable or printable compositions can be water-borne, solvent-borne, or UV curable liquids. Selection of the proper treatment includes the evaluation and optimization of multiple factors including print quality and adhesion to the substrate (of inks and/or primers). In some cases, the primer must survive the extremes of electroless copper plating solutions.
New primer compositions have been formulated enabling quality of printing of catalytic and functional inks on PET, COP/COC, PMMA, and PC. In some cases to be presented, these new primers enable the manufacture of fine copper microwires on challenging substrates – illustrating primer survivability in electroless copper plating chemistries while maintaining the required adhesion performance. Previously, only PET could be used in the manufacture of copper microwires.
With these new primer compositions, a broader selection of substrates can be used in high-resolution printing and plating processes enabling printed electronics products to serve new markets. These applications can include heaters, touch panels and sensors, transparent antennas, printed lighting, and more in a lower cost roll-to-roll manufacturing facility.