Super-absorbent polymer powder for use in e.g. diapers, packaging and soil improvers, obtained by pre-swelling polycarboxy-polysaccharide in water and then drying and surface-crosslinking resulting hydrogel

摘要

Polymer powder (I) which is post-crosslinked on the surface, absorbs water, aqueous or serous fluids and blood and is obtained by surface-crosslinking partly neutralized carboxyl group-containing polysaccharide(s), is based on a polycarboxy-polysaccharide which is pre-swollen in water in the uncrosslinked form and dried again before surface-crosslinking. Independent claims are also included for the following: (1) production of (I) comprising: (i) forming a hydrogel from an uncrosslinked polycarboxy-polysaccharide (II) and water; (ii) mechanically crushing and drying the hydrogel; (iii) pulverizing and classifying the dried hydrogel; (iv) coating the particles of the resulting polymer powder with a solution of crosslinker; and (v) performing the surface-crosslinking operation; and (2) water- or aqueous liquid-absorbing (I) obtained by the above method.