Лако-красочные материалы — производство

Oxidized starch is commonly obtained by aqueous alkaline hypochlorite treatment. A starch suspension at pH 8-10 is treated with hypochlorite (5-10% Cl based on starch) for long enough to produce the desired viscosity. Acid is liberated during the reaction, so base must be added to maintain the pH for optimum reactivity. The resultant starch contains a mixture of carboxyl and carbonyl oxygens. Some shortening of chain length is observed during the reaction, but as in acid modification, there appears to be little change in the crystalline region of the starch. Dried oxidized starch is generally whiter than unmodified starch, since the oxidation and subsequent rinsing tend to remove impurities that may be present in native starch. Oxidized starches behave similarly to the acid-modified starches upon gelling. However, the oxidized starches have greater tack and adhesive character, and thus they are used more frequently in adhesive prep­arations.