ACHEMA2009 - Additive selection and evaluation of dispersion stability for reformulation in the REACH process

Paper at

ACHEMA 2009
29th International Exhibition-Congress on Chemical Engineering, Environmental Protection and Biotechnology
11 - 15 May 2009 Frankfurt am Main / Germany

T. Sobisch, D. Lerche, LUM Berlin/Germany

Paper 7402, 05/15/09 11 a.m.

Rapid additive selection and evaluation of dispersion stability for reformulation in the REACH process

Selection of additives for stabilization of dispersions is a frequent task. This relates to practical issues like formulation of dispersions, optimization of preparation conditions, quality control and shelf life estimation. Due to European legislation (REACH) many companies are facing the problem to replace proven components in their formulations (low volume speciality compounds or problematic chemicals). This also applies to emulsifiers and emulsion based products.

A multisample technique based on analytical centrifugation is presented which allows for an accelerated study of demixing of dispersion like creaming, sedimentation and of separation of oil and water phases. Not only information on the extent of phase separation is provided but also the kinetics are measured directly in-situ. The latter is of great practical importance for estimation of shelf life and in relation to the engineering of separation processes but is also very useful in screening of additives for replacement.

The method was applied to check for alternatives to nonyl phenol based surfactants as emulsifiers for silicone oil emulsions. Due to the multisample approach one centrifugal run with 12 different samples was sufficient to identify more environmentally benign emulsifiers with identical or better performance. In a second run the efficiency of emulsifier combinations was tested.