The present invention relates to a composite material based on (a) a cellulose- or lignocellulose-containing material and (b) a composite as a binder, the composite resulting from the reaction of at least the components (i) a glycidyloxypropylalkoxysilane, (ii) an aqueous silica sol having a solids content of >20% by weight, (iii) an organic acid as a hydrolysis catalyst and (iv) n-propyl zirconate, butyl titanate or titanium acetylacetonate as a crosslinking agent. The present invention furthermore relates to a process for the production of said composite materials and the use of a composite (b) as a binder for the production of wood-based materials.