| This article describes the methods of photoreactivity adjustment of diverse kinds of acrylic pressure-sensitive adhesives. The need to replace solvent containing systems, which still have maintained a large market share in various areas, results in a further push of innovations in the development of photoreactive hot melt an the low viscosity systems acrylic pressure-sensitive adhesives. As oppose to the classical solvent containing or to the aqueous systems, the photoreactive hot melt or low viscosity systems provides the following advantages as reduction of environmental impacts to a minimum, saving of energy costs, no drying channel, high coating speed, and production possibility of thick self-adhesive product carrier-free tapes. From the photoreactivity adjustment of acrylic PSAs, the results according to their main performances as tack, adhesion and cohesion were observed for main chain modification using copolymerizable unsaturated photoinitiators. Photoreactivity adjustment of acrylic PSAs through the side chain modification using additionable photoinitiators is technical very complicated, because so much photoinitiators are not available on the market. Normally vinylation of polymer chain demands the addition of conventional unsaturated photoinitiators with high migration rate of toxic photolytic substances after UV-crosslinking. In this case the amelioration of important PSA properties is very doubtful. |
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