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Materialien für die LED-Verkapselung

Materials for encapsulating LEDs
: Domann, Gerhard; Collin, Daniela; Cronauer, Carola

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DE 102016104790 A1: 20160315
Patent, Elektronische Publikation
Fraunhofer ISC ()

The invention relates to a composite material comprising a polysiloxane-containing matrix, a dispersant, and dispersed particles with diameters in the μm to nm range, wherein (a) the polysiloxane-containing matrix has a higher refractive index and a higher surface tension than the dispersant at least in the non-cured state, is produced using at least two different silanes, and has aromatic groups and organic groups, the latter of which can be bridged together via a bridging agent, wherein both the aromatic groups as well as the bridgable organic groups are bonded to a respective silicon atom via carbon, and the matrix additionally has a bridging agent with at least two reactive groups for bridging the organically bridgable groups and if necessary a catalyst which is required for the bridging reaction such that the organically bridgable groups are reacted with the bridging agent at least partly via an addition reaction in the cured state, and (b) the dispersant has either groups which can be organically crosslinked thermally and/or under the effect of light or Si-H groups and (ii) aromatic groups. The particles with diameters in the μm to nm range are first mixed with the dispersant, and the resulting mixture is combined with the polysiloxane-containing matrix with the proviso that none of the aromatic groups of the composite are styryl groups or the proportion of styryl groups lies below 5 mol.%, preferably below 1 mol.%, based on the total mol. quantity of aromatic groups in the composite. The invention also relates to a composite produced from the composite material by means of a curing process and to methods for producing the composite material and the composite.