the composite film under vacuum when the composition b comprises functionalized nanometric silica the particles are generally dispersed in a volatile solvent removable for example by thermal evaporation or under vacuum during the preparation of the composite film a second glass sheet can be positioned on top of the stack of composite film porous film and polyester film to obtain a flat surface as the surface resin is liquid by the described process it is possible to obtain a semi finished product made of one or more layers of substrate a impregnated by composition b supported between two glass sheets the supported composite film can be cured by for example ultraviolet uv radiation other suitable methods to cure the film include exposure to heat microwaves e beam the composite film can be treated under pressure in the curing process or in a following step eventually using a heated press and after removal of the polymeric films for a time from 1 to 24 hours the temperature of the press can be preferably between 90 u00b0 c and 400 u00b0 c the applied pressure can be between 0 1 mpa and 20 mpa inert gas or vacuum can be used to prevent oxidation induced by high processing temperatures when the curing is complete the composite film acquires a solid not sticky surface the final step.