polysackaridderivat, som innehaoller aldehydgrupper, deras framstaellning ur motsvarande acetaler och deras anvaendning som papperstillsatsmedel.

摘要

Polysaccharide aldehydes having the general structuresuch as starch, cellulose and gum aldehydes, are useful for imparting wet, dry, or temporary wet strength to paper. They are prepared by a non-oxidative method which involves reacting the polysaccharide base, in the presence of alkali, with a derivatizing acetal reagent having the general structureand then hydrolyzing the acetal by adjusting the pH to less than 7, preferably 2-4. R is (CH₂)_n or a divalent aromatic group and n is 0 or greater; R', R⁶, and R⁷ are hydrogen or an organic group; R², R5, and R⁸ are (CH₂)_m with m being 1-6; R³ and R⁴ are hydrogen or a lower alkyl; Y is an anion; Z is an organic group capable of reacting with the polysaccharide base to form an ether derivative and selected from the group consisting of an epoxide, ethylenically unsaturated group, halohydrin, and halogen; R", if present, is a divalent organic group containing no reactive substituents; and A and A' are lower alkyls or together form at least a 5-membered cyclic acetal.