Conductive inks printed layers

A cost reduction area that could have significant opportunities for chemicals companies is the interest in cheaper track generation systems such as screen printed conductive inks and the conductive pastes that are being used to replace plated through holes (PTH). Copper-based inks are already being used to form crossovers and simple circuits, and the use of thick film techniques of multiple layer printing is being evaluated to replace some multilayer circuits. 

To ensure continuous conductivity along a printed line, conducting ink drops must be printed in an overlapping fashion. Often, creating a single line or film with acceptable conductivity requires more than one layer of ink. The additional layers can be printed either before or after the previous layers have dried. 

Electronic applications for Bayer s Desmopan thermoplastic PU film include a solar cell encapsulation process. In November 2005, Bayer revealed that its new manufacturing process for the innovative carbon nanotubes had reduced their manufacturing cost. Bayer has also introduced formable PC films which incorporate EMI/RFI shielding. This is obtained by printing them with conductive ink or by dispersing the ink into the cap layer of the sheet. 

Fig. 9.27 (a) The enzyme/MWCNT/PS screen-printed thick film electrochemical detector, top view, (b) cross-section of the detection area of enzyme/MWCNT/PS screen-printed detector, (c) schematic drawing showing structure of HRP/MWCNT/PS composite (a) polycarbonate (PC) substrate, b) insulator layer, (c) HRP/MWCNT/PS conducting composite, d) silver contact for the working electrode, (e) carbon ink contact layer. (From [20])... 

Letterpress. This is the oldest printing process stiU in use. It continues to be replaced by newer printing processes. Printing is conducted from a raised image area of the printing plate. Inks in the printing process are transferred directly from a raised area to a substrate. The printing plates contain a thick layer of photopolymer (often a mixture with polymer such as poly(vinyl alcohol) deposited over a plastic or aluminum base. 

The special properties of nanomaterials, such as those currently used as the conductive "pigment" in conductive inkjet inks, will be exploited more and more in advanced second-generation products. New inks will be developed to print additional electronic functionalities such as resistors, capacitors, and semiconductors, thereby enabling inkjet printing of complete electronic components and devices. Inkjet s capability to layer materials and build 3D structures will be further developed for microelectronics applications. These efforts have already been initiated in universities, research institutes, and commercial entities — in the large established ink companies as well as smaller startups financed by joint VC and government funding. 

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