| 摘要 |
<p>The method comprises chemical modification of a starch (pref. from cereals) of hydration degree 10-20% and extrusion in a double-spiral press, the extrusion temp., previous degree of hydration, dwell time in the press and pressure being so regulated that the product contains >=25, pref. >=45 wt. % water-soluble component. Chemical modification comprises esterification, etherification; acid or alkaline hydrolysis, oxidn. and/or dextrinification, modification and extrusion treatment can be carried out sequentially or simultaneously. The new prods. are used in (a) textile industry (e.g. for sizing); (b) paper making (e.g. for coatings); (c) adhesives (e.g. for making gummed paper); (d) in crude oil drilling muds; (e) making building materials etc. and as additives for casting sands; (f) foods as texturising viscosity-modifying or water-retaining agents and (g) pharmaceuticals, esp. as a filler. The prods. can be produced with a given viscosity over the entire range of solid contents and they are at least as effective as those made from more expensive potato starch. They are prepd. without use in aq. slurries so that waste disposal problems are avoided and energy requirements reduced. They are more easily dissolved in water without formation of lumps.</p> |
