Tailor-made performance profiles by the flexible structure of polyvinylamines

Polyvinylamines (IPVAm) are a new class of cationic polymers. They are synthesized from vinylformamide (VFA), a monomer for which BASF Aktiengesellschaft has developed a large-scale manufacturing process. The very pure monomer is polymerized to polyvinyl-formamide, from which the required polyvinylamine is subsequently prepared by hydrolysis. The polymers obtained by this route can be varied within very wide limits by adjusting their molar mass up to 30 million g/mol, and their charge density can be chosen by the degree of hydrolysis. This approach makes it possible to cover the whole spectrum of cationic charge densities and molar masses required for paper chemicals. This flexibility makes these products extremely versatile. Their performance can be tailored specifically in order to solve a variety of different problems in the papermaking process. The range of applications can be extended by using them in combination with existing paper chemicals, which offers additional scope for optimizing the performance of all of the chemicals used in the paper mill. Polyvinylamines can be used to boost retention and drainage, to fix anionic substances and size, and to increase the wet and dry strength of the paper. Apart from the individual effect that polyvinylamines display, the interaction between different performances of the product offers enhanced scope for optimization and makes it possible to find integrated solutions to papermaking problems. In particular, polyvinylamines offer new perspectives for increasing the strength of paper by modifying starch for wet end addition. An important feature of polyvinylamines is that no formaldehyde or organic halogen compounds are present. The environmental advantages of this new group of substances is underlined by the fact that they have been approved by the German health authorities for use in food contact applications and in coffee filters and tea bags, etc. (BgVV recommendation XXYVI, papers for food contact and recommendation XXXVI/1 hot water filter papers). This opens up the unlimited possibility of making use of the novel performance characteristics of polyvinylamines in the production of speciality paper grades.