Wet end interactions and effect on synthetic size response

摘要

The ability and methodology to measure both retention and sizing response in one experiment is something of interest to those of us involved in research and development of chemical additives for paper making systems. A disadvantage of most laboratory sheet making methods is the quiescent period necessary to get a good formation of the sheet on the wire. Good formation is essential for most of the normal methods used to measure sizing. These methods often involve a dilution and even a thermal shock on the wire because of the necessity to have the wire flooded. It is also well known that good retention of the fines and filler fractions is important, since the because of the high surface area and charge, sizing agents have a high affinity for these components. The DDA (Dynamic Drainage Analyser) equipment is widely used to measure the dynamic drainage characteristics of a paper making furnish and the effects of chemical additives. Additionally turbidity measurements or other tests can be used to estimate the total retention. We had an interest to be able to utilise this equipment to evaluate the sizing response of systems, while being able to vary retention system components to simulate real paper making systems. The DDA equipment in combination with dynamic contact angle measurements has been evaluated as a potential method combining optimisation of the retention and drainage effects with the internal sizing effect. It is possible to evaluate the effects and interactions of different retention system components on the sizing response of the system. Application of this methodology has been made in the development of newer systems for the Paper and Board industry.