Impregnations are systems which prevent the penetration of water and solutions into the concrete without stopping the escape of internal moisture from the concrete. In general the penetration of impregnation solutions is improved the smaller the molecules of the impregnation materials are. After impregnation, the concrete must be protected from rain at least 24 hours to prevent the washout of the siliconate. Resin or Casting impregnation seals the porosity inherent in metal castings, powdered metal parts and composite materials.

A material is impregnated into leather by incorporating the material into microcapsules and then applying microcapsules to the leather materials by means of a suitable process. A roller coating process is described in which the material is applied to a roller under which the leather material passes while it is compressed. Alternatively, the micro-capsules may be applied to the leather by drumming-in in a wet process.