SDK Develops Microwave-based New Materials for Printed Electroni

SDK Develops Microwave-based New Materials for Printed Electronics 
Offering Conductive Ink, Curing Unit, and Conductive Adhesive for Manufacture of
Electronic Circuits on FPCs 
Tokyo, June 3, 2013 - (JCN Newswire) -  Showa Denko K.K. (SDK) has developed an
innovative microwave-heating printing technology to form electronic circuits on
flexible printed circuit substrates (FPCs), in which plastic films and other
materials with low heat resistance are used. 
As part of the new technology, SDK has developed a printable silver/carbon
hybrid conductive ink and an ink-curing unit.  SDK has also developed a
printable conductive adhesive usable in microwave-heating, thereby
significantly reducing migration[1] that causes deterioration in product
quality.  As a result, it has become easy to form electronic circuits on FPCs
and mount devices by printing. 
SDK will, through its subsidiary Shoko Co., Ltd., start selling the ink-curing
unit, as well as offering samples of the silver/carbon hybrid conductive ink
and the conductive adhesive.  These products will be exhibited at "JPCA
Show 2013" to be held at Tokyo Big Sight from June 5 through 7. 
1. Silver/carbon hybrid conductive ink and ink-curing unit 
In printed electronics, conductive inks printed on substrates are heated and
cured to form electronic circuits.  When low-heat-resistant substrates and
parts are to be used, it becomes necessary to heat required portions only,
using selective heating technologies.[2] 
Microwave heating is one of the selective heating technologies, as is Photonic
Curing(TM) process technology already introduced by SDK. Microwave heating is
suited for printing on low-heat-resistant plastic films and for roll-to-roll
continuous printing.  Furthermore, microwave can penetrate into a substrate,
enabling the formation of conductors inside a substrate and the bonding of
internal parts. 
In the conventional microwave heating, there is a problem of spark discharge
involving conductive inks that contain metallic materials. SDK has developed a
new technology, jointly with Professor Yuji Wada, of Tokyo Institute of
Technology, and The National Institute of Advanced Industrial Science and
Technology (AIST), to control spark discharge by separating microwave's
magnetic field and electric field and applying the fields separately in
In our newly developed silver/carbon hybrid conductive ink optimized for this
technology, carbon particles (which do not develop a phase change during
heating[4]) have been added to silver particles.  This step ensures uniform
curing of the ink under microwave heating, preventing a non-uniform
distribution of conductivity.  Conventional silver inks tend to develop, upon
absorption of microwave, a non-uniform phase change due to melting, resulting
in non-uniform distribution of conductivity. 
This development forms part of the New Energy and Industrial Technology
Development Organization's (NEDO) research project on "Development of
Both Metal Thin Film Fabrication Technology with Microwave and Its Patterning
Technology," coming under "Research and Development for Nanotech and
Advanced Materials Applications." 
2. Halogen-free conductive adhesive 
In the wiring of electronic circuits, silver-containing conductive adhesives
are generally used to ensure conductivity. However, silver tends to cause
migration due mainly to halogen components contained in peripheral materials.
SDK has developed, jointly with Professor Katsuaki Suganuma, of Osaka
University, a halogen-free conductive adhesive, enabling substantial reductions
in migration. 
This adhesive can also be used with the newly developed microwave-heating
equipment.  The adhesive can be printed on a plastic film, and subjected to
heating and curing with devices being mounted on the substrate. 
The adhesive is based on the epoxy resin manufacturing technology[5] developed
jointly by SDK and AIST as part of research projects in the areas of
"Development of Fundamental Technologies for Green and Sustainable
Chemical Processes; Development of Innovative Chemical Process-Product with
Less Waste Emission; and Fundamental Technology Development of Innovative
Oxidation Process." These projects were sponsored by the Ministry of
Economy, Trade and Industry in 2008, and by NEDO in two stages, namely, in the
2009-2011 period and in 2012.  Resin formulations have been optimized for
conductive adhesive applications. 
Printed electronics—the technology to manufacture electronic circuits through
printing—is expected to be increasingly used as an efficient production method
for electronics, electric appliances, and transport machinery. SDK will
continue to work to develop and commercialize materials for printed electronics
through collaboration with outside partners.
1. Migration: Movement of metals on the surface of or inside a nonmetallic
medium, resulting in short circuit.
2. Selective heating: Technology to heat selected portions only.  In the
Photonic Curing(TM) process technology and microwave heating, only metallic
substances, such as silver, absorb the energy and generate heat.
3. This microwave heating equipment is designed and produced by Fuji
Electronic Industrial Co., Ltd.
4. Phase change: A phenomenon in which the arrangement of molecules/atoms
changes substantially after heating or cooling of substances.
5. A new process for producing alicyclic epoxy compounds, using hydrogen
peroxide as oxidizing agent.  Chlorine is not used in the production.
(Announced by SDK on September 18, 2012.) 
About Showa Denko 
Showa Denko K.K. ('SDK'; TSE: 4004, US: SHWDF) is a major
manufacturer and marketer of chemical products serving a wide range of fields
ranging from heavy industry to the electronic and computer industries. SDK
makes petrochemicals (ethylene, propylene), aluminum products (ingots, rods),
electronic equipment (hard disks for computers) and inorganic materials
(ceramics, carbons). The company has overseas operations and a joint venture
with Netherlands-based Montell and Nippon Petrochemicals to make and market
polypropylenes. In March 2001, SDK merged with Showa Denko Aluminum Corporation
to strengthen the high-value-added fabricated aluminum products operations, and
is today developing next-generation optical communications-use wafers. For more
information, please visit . 
Showa Denko K.K. (SDK)
Public Relations Office
Tel: +81-3-5470-3235 
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