APPLICATION OF TITANYL SULPHATE FOR MANUFACTURING PAPER CONTAINING TIO2 FILLER

The aim of research was first, to study the interactions between components for finding out how pH effects on ζ-potential, dewatering rate and retention of TiO2/MCC mixtures with/without titanyl sulphate in order to find a way to titanyl sulphate hydrolysis in a papermaking process. The maximum heterocoagulation interactions between TiO2, MCC and TiOSO4 were revealed in the pH range 4.4–5.6. Second, handsheets made from refined chemical pulp, titanyl sulphate and TiO2 at pH 4.4 were investigated. The handsheets were formed and studied conventionally and with scanning electron microscopy (SEM). It was shown that titanyl sulphate hydrolysis leads to formation of translucent polymer film covering the fibres and TiO2 particles. The maximum first-pass ash retention reached is lower than its values usually obtained with an organic polymer. Addition of titanyl sulphate led to higher strength, but lowered opacity and brightness compared to a reference sample. The use of low dosage of titanyl sulphate together with a filler improved air permeability. As there exist certain advantages/disadvantages of titanyl sulphate application, extended research is needed to find suitable conditions for its applying to mass paper and board grades production.