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Novel Photoinitiators for Free Radical Polymerization

IP.com Disclosure Number: IPCOM000101298D
Original Publication Date: 1990-Jul-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 1 page(s) / 38K

Publishing Venue

IBM

Related People

Doetschman, DC: AUTHOR [+3]

Abstract

Disclosed is a novel class of free radical photoinitiators comprised of covalently bonded initiator/sensitizer moeities and a process for their synthesis (see the figure).

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Novel Photoinitiators for Free Radical Polymerization

       Disclosed is a novel class of free radical
photoinitiators comprised of covalently bonded initiator/sensitizer
moeities and a process for their synthesis (see the figure).

      Conventional free radical photoinitiators generally possess
poor extinction coefficients at the lower energy mercury arc lamp
lines, and/or require the addition of a suitable sensitizer, at
sufficiently high concentrations, for optimal performance (1,2).  At
high sensitizer loadings, the absorptivity of resist formulations is
so pronounced that uniform through cure becomes impossible - image
degradation and undercut result.  At low sensitizer concentrations,
poor photospeed renders the initiator/sensitizer couple useless.

      Covalently binding initiator/sensitizer pairs provide several
advantages: a bathochromic shift in the absorption spectrum for
enhanced spectral overlap with the mercury arc output, and the
potential for near unity quantum yields of initiator free radical
fragments.  These attributes, in comparison with traditional
photoinitiators, permit lower concentrations of the intramolecularly
sensitized initiator, resulting in greater photospeeds and deeper
through cure.

      References
(1)  W. Rutsch, G. Berner, R. Kichmayr, R. Husler, G. Rist and N.
Buhler, Organic Coatings, Science and Technology, eds. G. D.  Parfitt
and A. D. Patsis, Marcel Dekker, Inc., New York, 8, 175, (1986).
(2)  N. Turro, ...