Nanometer sized particles for viscosity controlled binders for silk screen printing

A water based synthesis route to PbOSiO2B2O3ZnO gels and glasses has been developed. In the present study the gel was used for the substitution of organic silk screen printing media and additives in a silk screen printing paste for the decoration of glass with a black enamel. Interparticle forces of the gel particles can control the viscosity of a paste, containing 30 wt% of the wet gel and 70 wt% of a commercially available black enamel powder. Beside the rheology controlling function, a consequence of polycondensation of the gel during drying of the printed pastes is, that the sol—gel material acts as a binder. The composition of the gel ensured that during firing the sol—gel material is densified to a glass with properties suitable for the firing process at temperatures between 560°C and 640°C. Because of the particular inorganic gel which was used, no residual organic groups have to be removed during firing.