Method for improving water resistance of injection moulded starch prod. article

摘要

The mfr. of an article by injection moulding a starch prod. comprises: improving the water resistance of the article by treatment with an aq. soln. of (NH4)2SO4 and/or MgSO4 or with a mixt. of H2O and a water-miscible organic solvent. Pref. the article is treated with a satd. soln. of (NH4)2SO4 and/or MgSO4, esp. a mixt. of H2O and ethanol (vol. ratio = 10/90-90/10). Treatment time is 1-90 min. A post treatment with H2O is carried out for 1-60 sec. Starch prod. consists (largely) of native potato starch (or is derived in the case of a starch hydrolysate) and opt. includes a salt; 5-30%wt. of (NH4)2SO4 and/or MgSO4; 5-50%wt. a supplementary plasticiser; upto 10%wt. a flow improver e.g. castor oil or lecithin; upto 40%wt. (10-30%wt.) a starch hydrolysate with a DE /}40 (5-30); and upto 50%wt. a reinforcing natural fibrous material.