| abstract |
PCT No. PCT/EP94/04221 Sec. 371 Date Jun. 24, 1996 Sec. 102(e) Date Jun. 24, 1996 PCT Filed Dec. 19, 1994 PCT Pub. No. WO95/17455 PCT Pub. Date Jun. 29, 1995The present invention relates to cross-linked synthetic polymers based on acrylic acid and its derivatives, which have a high absorption capacity and an improved absorption rate for water, aqueous solutions and body fluids, to a process for their production by radical polymerization under such conditions that polymers are obtained which have a porous structure and a swelling degree-dependent particle density so that the polymer particles are floatable in water or aqueous liquids. The present invention further relates to the use of these polymers for the absorption and/or retention of water and for the release of water and/or an active substance solution to a surrounding medium. The porous structure of the polymers is formed by nitrogen dispersed in the polymer, with at least one azo compound being added to the aqueous monomer solution as polymerization initiator and blowing agent, which azo compound has a half-time of at least 10 hours at a temperature of 30 DEG to 120 DEG C. |