ABSTRACT
Surface-active agents are used as process aids and additives in the end-use applications of many emulsion polymers and thermoplastics, imparting specific properties to the polymers in question. Applications include foaming agents for emulsion polymers and PVC plastisols, antistatic agents and viscosity modifiers for plasticised PVC and defoamers for water-based polymers. Most water-based synthetic polymers contain residual emulsifiers, which are frequently high-foaming anionic surfactants. In some applications, this may be a benefit, particularly in foamed latex for carpet, textile and upholstery backings. In many other areas of emulsion polymer production and processing the problems created by residual emulsifiers necessitate the addition of antifoams or defoaming agents. Although the terms ‘defoamer’ and ‘antifoam’ are often used interchangeably, strictly a ‘defoamer’ (or ‘defoaming agent’) is used to break down foam that is already present, whereas an ‘antifoam’ (or ‘antifoaming agent’) is used to prevent foam formation. The latter is usually the most cost-effective means of chemical control.
