Silico-acrylic compositions, process of preparation and use as coatings which can be hardened either thermally or by irradiation

Silico-acrylic compositions, fluid, transparent and incolorescomme water, stable over time, and polymerizable thermally parrayonnement by free-radical mechanism, with very low water content (inférieureà 1.5%) and volatile solvent, containing silica , a silane and multifunctional acrylic unmonomère, wherein the silica is in the formede individualized particles, of average diameter between 5 and 100 nm, not linked together by siloxane bonds, the silane is a vinylsilane deformule (I) H2C = CH - Si (oR) 3 (I) wherein R represents a methyl or ethyl radical, in which multifunctional acrylic lemonomère is tripropylene glycol diacrylate TPGDA glycoldésigné the quantity of vinylsilane of formula I is between 0.1 and 0,01millimole millimole per m 2 of silica used and which are transparent etincolores such as water and stable over time and method of preparation.