Лако-красочные материалы — производство

Because of their hydroxyl groups, alcohols (Figure 4.2) differ from hydrocarbons by having a higher polarity and a stronger tendency for hydrogen bonding. The mass ratio between the non-polar hydro­carbon chain and the hydroxyl group governs the solvency of alcohols. Lower alcohols are good solvents for polar resins such as shellac, amino resins and phenolic resins, but they are poor solvents for non-polar binders such as oils or oil modified alkyds. Polarity also affects water solubility of alcohols; lower alcohols, up to propa­nol, are water soluble, while higher ones are partially soluble, with progressively decreasing water solubility with increase in number

Figure 4.2: Examples of alcohol solvents

of carbon atoms in the molecule. Higher alcohols are mainly used as diluents in combination with esters. Higher alcohols can also be used to improve the storage stability of baking enamels formulated with etherified crosslinking resins.