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COSI 2006
June 26th
- June 30th 2006
Noordwijk, The
Netherlands |
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2nd
Coatings Science International 2006 |
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Kurt Dietliker |
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Ciba Specialty
Chemicals Inc., Basel, Switzerland |
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Title Lecture |
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Advancements in
Photoinitiators – opening up new Applications for Radiation Curing |
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Abstract |
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Over the past decades,
radiation curing has found widespread use in an increasing number of
industrial applications. Photoinitiators are key components in all
photopolymerizable formulations, which allow the efficient
transformation of the energy of light into chemical energy in the form
of initiating species. A variety of efficient photoinitiators for
different applications is today commercially available and used in
coatings, printing inks or electronic materials. |
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However, several
challenges for radiation curing still remain. These include for example
the curing of thick or highly pigmented coatings or of coatings applied
on three dimensional objects. Odor and extractables in the cured
coatings are another issue of concern. Newly emerging applications
eventually create novel requirements for the curing process and the
properties of the cured material. |
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Further improvements
of photoinitiators and the development of new compounds are therefore
essential for the further expansion of the UV curing technology. Modern
photoinitiators are in fact more than just catalysts for the
polymerization process: they are an integral part of sophisticated
formulations, providing excellent properties in the manufacturing
process and during the service time of the cured article. This will be
illustrated by some recent developments in photoinitiators. |
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Well-approved
initiator classes for radical photopolymerization have been
significantly improved and optimized for use in coatings for outdoor
applications and in printing inks. The new compounds allow fast cure and
provide excellent properties to the cured coating, including no
yellowing after cure and upon long-term weathering and low odor and
extractables in printing inks. |
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A new type of
photoinitiator has recently been introduced for use in color filter
fabrication. The compound can meet the challenging requirements
regarding light transmission in the resist material, thereby
guaranteeing the purity of the color in the display |
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The development of
photolatent amines, a completely new class of photoinitiators, has
eventually made new resin types accessible for radiation curing. Either
conventional coating formulations or newly designed formulations can be
used with these photoinitiators. The alternative base catalyzed curing
mechanism allows to overcome some of the limits of radically curing
formulations. Coatings of excellent performance are obtained, and the
scope of radiation curing is considerably expanded by this new
technology. |
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Biography |
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Kurt Dietliker studied
organic chemistry at the University of Zurich and received his PhD for a
thesis on the photochemistry of aminoazirine and isoxazole heterocyles.
After a postdoctoral year at the University of Fribourg focusing on the
elucidation of the di-p-methane rearrangement, he joined the research
department of the Additives Division of the former Ciba-Geigy AG in
Marly. |
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After a short time
dedicated to other topics, he became involved in photoinitiator
research. Over the years, his work focused on the development of several
new photoinitiators for radical and cationic curing. In addition to
numerous patents and scientific papers in this field, he is the author
or co-author of three books on photoinitiators. |
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Currently he holds the
position of a Senior Research Fellow and is responsible for the
development of new photolatent acids and bases for the Coating Effect
Segment of Ciba Specialty Chemicals Inc. in Basel. |
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