Radiation curable silicones

R. P. Eckberg, "Chemistry and Technology of Radiation Curable Silicone Release Coatings," in D. Satas, ed.,. Advances in Pressure Sensitive Adhesives, Satas Associates, Warwick, R.I., 1992. 

Among the most successful of the new radiation-curable silicone coating systems are compositions Incorporating cycloaliphatic epoxyfunctional silicone polymers with compatible iodonlum salt photocatalysts (1 - S ) The syntheses, structures, UV cure response, and other properties of these materials and some of their derivatives and monomeric homologs are discussed In the balance of this chapter. Their specific application for release coatings has been described In great detail elsewhere (5.6 > and Is not the subject of this paper. 

R. P. Eckberg, B. D. Shepherd Radiation Curable Silicone Coatings Controlled Release Design, RadTech North America, Orlando 1994, p. 507 - 514. 

Eckberg RP, Sheperd D. Radiation curable silicone coatings controlled release design. In Proceedings of the RadTech America. Orlando 1994 507-513. 

Radiation-curable epoxy acrylates, 10 450 Radiation cures, silicone network preparation via, 22 567-569 Radiation curing coatings, 7 133-135 of printing inks, 14 314 Radiation damage, ion implantation and, 14 435-436 Radiation drying coatings, 7 29-30 Radiation effects... 

In 1983, radiation curable 100 % solvent-free silicone acrylates were introduced into the market [4], This system provide the opportunity to be cured by either ultraviolet light (UV) or electron beam (EB). Similar in concept to peroxide initiation, silicone acrylate systems employ photoinitiators to generate free radicals and initiate cure, which is based on the polymerization of the acrylic C=C double bond via a radical chain reaction. 

Typical physical properties obtainable with UV cured silicones are provided In Table I. Incorporation of reactive unsaturation into the silicone polymer backbone In combination with a photosensitization system provided the photocure capability. Properties of a standard heat-cured encapsulant developed for use on semiconductor devices, Dow Corning HIPEC R-6103, are provided for comparative purposes. Clearly, introduction of a photocrosslinking mechanism into a siloxane type composition has afforded the desired result. The one-part, solventless, UV curable silicone composition cured rapidly upon exposure to UV radiation, providing a cured composition which has retained the typical properties that make silicones so attractive for protection of semiconductor devices. 

Frances, R.S. and Edelman, R., Ultraviolet radiation-curable acrylic polymer pressure sensitive adhesives, Japanese Patent JP 200004-4887, 2000 Frances, J.M., Delchet, L., Amaut, C., Gambut, L., Pressure-sensitive adhesive silicone compositions. World Patent 0310257, CA-2003-97495 2003. 

Majof silicone suppliers have been developing radiation-curable coatings for some time now the solventless systems lend themselves to this approach since all the space radiant energy can be directed at the polymer system for curing, and none wasted for solvent evaporation or in the substrate. The energy source referred to may be either ultraviolet or electron-beam radiation, and the objective is a very rapid zero-temperature controllable cure, with much of the control occurring through the intensity of the source. 

Chem. Descrip. Silicone-modified EPDM elastomer Uses EPDM for automotive applies, such as radiator and heater hose, ignition cable, spark plug boots, and for appliance wire, molded elec, goods, rolls for copiers, laminating, coil coating Features General-purpose elastomer with optimum heat resistance peroxide-curable... 

UV-curing adhesives are available in a number of chemical systems, most of which are polymer based. These systems include acrylics and acrylates, epoxies, polyurethanes, polyesters, silicones, and vinyl and vinyl esters. The most common UV-curable adhesive is the acrylics. Specially modified acrylic and epoxy adhesives can be cured rapidly by UV radiation. In the case of epoxy adhesives, the adhesives can be pre-irradiated after application to the substrate before closing the bond line. These adhesive systems are offered by most major suppliers. ... 

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