Polysaccharide derivatives containing aldehyde groups on an aromatic ring, their preparation from the corresponding acetals and use in paper

Abstract

Polysaccharide aldehydes having the formula ##STR1## or Sacch--O--CH.sub.2 --Ar--CHO (II) such as starch, cellulose, and gum aldehydes, are useful as paper additives for imparting strength and as the granular or gelatinized portion of a corrugating adhesive. Those having formula I are prepared by a nonoxidative method which involves reacting the polysaccharide base, in the presence of alkali, with a derivatizing acetal reagent having the general structure ##STR2## and then hydrolyzing the acetal by adjusting the pH to less than 7, preferably 2-4. In the formula Ar is an aryl group, optionally containing an ether linkage, or an alkaryl group and A and A' are lower alkyls or together form at least a 5-membered cyclic acetal. The polysaccharide aldehydes are crosslinked by the addition of selected polyfunctional crosslinkers such as an aliphatic primary polyamine or polyketone.

Dependencies are inferred from the claim text.