Additives For Emulsions And Dispersions In Flexible Foam Formulations

摘要

Incompatibility issues are well known even in today’s standard foam formulations. A typical example is the use of fillers such as calcium carbonate in polyol components. Also in more special foams such as supersoft and viscoelastic grades it is essential to use formulation components of different chemical compositions. The products range from limited solubility to complete incompatibility. The desired qualities can only be achieved when homogeneous mix of the formulation occurs. Inhomogeneity can result in a reduction of physical properties. In the future, the situation is likely to become more complex. In an effort to meet the ever changing market demands, typically requiring improved properties new flexible foam formulations are being tested and introduced. Many include new materials increasing the potential for the formulators to face compatibility issues more often than in the past. Typical problems are phase separation of liquids, sedimentation and flotation of solid particles or agglomeration of finely dispersed materials. Without proper mixing and sufficient stabilization of the emulsions and dispersions, the targeted improvements are likely be hindered due to phase separation of the incompatible formulation components. Sources for incompatibility in liquid to liquid blends are from the use of a combination of hydrophilic and hydrophobic polyols or the application of new polyols from renewable sources with high hydrophobic characteristics. Problems with sedimentation of solid particles are observed when fillers, solid flame retardants, pigments and powders are part of the formulations. The paper will elaborate concepts of the stabilization of solid-liquid and liquid-liquid interfaces. With the help of examples the paper will offer additive solutions for the application of incompatible formulation components, hence allowing new and interesting physical properties for future flexible foams.