Process and assembly to make printing ink in which the pigments are flushed in a first stage and salts are then washed out

摘要

In a process to make printing ink, a mixed aqueous sludge containing lipophilic pigment and a lipophilic binding agent is fed to a process in which they are subjected to shear and stretch forces. The lipophilc pigments are flushed by the binding agent and water is then drained away. The residual semi-liquid mass is then surrendered to a second process in which it is subjected to sheer, stretch and compression and water drained away, producing a semi-liquid mass in which the pigment is disperses within the liphophilic binding agent. The resulting semi-liquid product is removed either as in intermediate product or as an end-product. The first-stage color pigment is pref. 3 to 6 per cent of the sludge. Most of the water drained from the first-stage product is admixed to the next incoming first-stage batch. Hot distilled water is admixed to the ingredients in the second stage. Water is drained twice from the second stage, prior to further expulsion of water as steam in the presence of a vacuum. The first-stage shear rate is pref. 1000/s to 50,000/s, varying continuously between minimum and maximum values. The liphophilic pigment is a solid which when flushed translates from an aqueous phase into the binding agent oily phase. The first phase takes place at pref. 40 to 90degreesC. Also claimed is a commensurate assembly in which the pigments are flushed in a first stage, and salts are then washed out.