摘要 |
<p>PROCESS AND COMPOSITIONS FOR PHOTOPOLYMERIZATION The present invention relates to the use of arylglyoxalate, ring substituted arylglyoxalate and heterocyclic glyoxalate compounds as photoinitiators in the photopolymerization of monomeric and polymeric compositions under the influence of actinic radiation. BACKGROUND OF THE INVENTION Photopolymerization of unsaturated compositions wherein a photoinitiating compound is included in the polymerizable mass is well known in the art. The process has many advantages over thermal polymerization and is particularly useful where long holding life combined with rapid hardening at low temperature is desirable. Photoinitiating compounds must absorb light and utilize the energy so acquired to initiate polymerization. A large number of compounds have been found useful as photoinitiators for the polymerization of unsaturated compounds. Among those heretofore in most common usage in industry are the benzoin ethers of primary and secondary alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol and isobutyl alcohol. Also, compounds such as phenyl glyoxal and 1-phenyl butane-1,2-dione are disclosed as photosensitizers in U.S. Patent No. 2,413,973. Additionally, various acetophenone compounds such as 2,2-diethoxyacetophone are claimed to have photoinitiating capability in Patent NO. 3,715,293. While particular industrial applications often dictate certain requisite characteristics the primary determinants of</p> |