Das Projekt "Papermaking chemistry aspects of environmentally friendly ecf and tcf pulps" wird vom Umweltbundesamt gefördert und von Papiertechnische Stiftung durchgeführt. General Information: Chemical additives are more and more important for an effective manufacture of high quality paper products. The background of this project is the importance of chemical additives (paper chemicals) in paper manufacture and the rapidly increasing use of new types of non-chlorine bleached pulps, i.e. elementary chlorine-free (ECF) and totally chlorine-free (TCF) pulps. Paper chemicals are used in the paper production as process chemicals or as functional chemicals. A process chemical is e.g. a charged polymer used to flocculate fine material. A functional chemical is e.g. added to increase the strength of the paper. The new pulps can influence the use of paper chemicals in at least two ways. The interaction between the fibres and the paper chemicals can be influenced which will influence the effect of the paper chemicals in the produced sheet. This will create a new, more difficult, situation for the use of paper chemicals. The project will give guidelines how to optimize the application of chemical additive in papermaking from ECF and TCF pulps and thereby reduce the papermaking costs. The type and the amount of substances that is dissolved from the pulps will depend on e.g. the chemical environment and whether the pulp has been dried or not. It is therefore important to investigate the extent of carry-over of substances from the pulp mill to the paper mill. We will perform pulp mill measurements to investigate the carry-over. The effect on wet end additives of new ECF and TCF pulps and of dissolved and colloidal substances carried by these pulps will be clarified. Another aspect is that when paper chemicals, such as retention aids and sizing agents, are used, paper chemicals transfer between components in the furnish and in the white water system. This can influence the performance of paper chemicals. It is known that the amount of transfer of paper chemicals depends on the chemical environment, i.e. the ionic strength. It is not known to what degree the transfer is influenced by dissolved and colloidal substances originating from pulps. The papermaking system is highly dynamic and computer simulations of the process circuits in a paper mill have gained increased attention. An increased knowledge in the process dynamics of both the transfer of paper chemicals and the dissolved and colloidal substances is highly needed. Pilot paper machine experiments will make it possible to make controlled experiments of the influence of dissolved and colloidal substances on the effect of paper chemicals. A deeper knowledge of the fundamental paper chemistry aspects of using ECF and TCF pulps combined with pilot and mill trials will give great possibilities to control the papermaking process better in order to improve the paper quality. The environmental relevance is naturally high because a better process knowledge leads to reduced effluents. Prime Contractor: Swedish Pulp and Paper Research Institute; Stockholm.