Particulars of and troubleshooting for softening finishes

Microemulsions of softeners, mainly amino-modified silicones, give special softening effects. Their main advantage is high emulsion stability. This is important for applications with high shear, as in jet or package dyeing machines. Emulsions that do not have excellent shear stability can actually breakdown and deposit softener particles on equipment and fabric that are either very difficult or impossible to remove. In Table 3.2, some characteristics of normal and microemulsions are compared. 

Emulsion stability When the stability of a normal (not micro-) emulsion is very high in an exhaust treatment, then the softening effect decreases. An emulsion of moderate stability gives the best results, probably because small drops of the emulsified softener can exhaust to the fibre surface. Poor emulsion stability causes stains. 

Reactive softeners Some softeners have functional groups that can react with the corresponding groups of some fibres, for example A-methylolated amines with the hydroxyl groups of cellulose (compare the mechanism of the crease resistance finish). The result is a very durable finish, combined with the typical advantages and disadvantages of this crosslinking chemistry, as discussed in Chapter 5. 

Softeners and thermomigration of dyes Many hydrophobic softeners are 

Size of the drops (nm) 150-300 10-20 See also Holzdorfer no droplets, only micelles 

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