公开(公告)号：DE19849499A1

公开(公告)日：2000-05-04

申请号：DE19849499

申请日：1998-10-27

Applicant: BASF AG

Inventor： DENTLER JOACHIM ,  HERFERT NORBERT ,  KLOTZSCHE HELMUT ,  SCHLIWA RONALD ,  STUEVEN UWE

IPC: B01J20/26 ,  B01J20/30 ,  B29B13/06 ,  C08F6/00 ,  C08J3/00 ,  C08J3/12 ,  F26B1/00

Abstract: The present invention relates to a complete drying method for hydrogels, whereby the following steps are carried out successively: a) the hydrogels are contact dried or dried by convection, b) the hydrogels are pre-crushed, c) the pre-crushed hydrogels are ground by means of a coarse crushing mill or a crushing roller mill, d) the damp elastic hydrogel particles are separated, e) the damp elastic hydrogel particles are finally dried.

公开(公告)号：DE19846413A1

公开(公告)日：2000-04-13

申请号：DE19846413

申请日：1998-10-08

Applicant: BASF AG

Inventor： DENTLER JOACHIM ,  HERFERT NORBERT ,  SCHLIWA RONALD ,  STUEVEN UWE ,  ENGELHARDT FRITZ

IPC: A61F13/15 ,  A61F13/53 ,  A61L15/00 ,  A61L15/60 ,  B01J20/26 ,  B01J20/30 ,  C08F2/01 ,  C08F8/44 ,  C08F220/06 ,  C08F251/00 ,  C08F261/04 ,  C08F283/00 ,  C08F283/02 ,  C08F283/06 ,  C08F291/00 ,  C08J3/12 ,  C09K3/00 ,  C08F6/02

Abstract: Preparation of a water-swellable hydrophilic polymer (I) involves: (a) radical (co)polymerization of hydrophilic monomer(s) (II), or graft (co)polymerization of (II) onto a substrate, where the average degree of neutralization of acid monomers is 0-40 mol. %, (b) comminuting, (c) post-neutralizing (60-85 mol. %) in a shredder under specific conditions; (d) charging the particles to a band drier, without further mechanical shear; (e) drying; and (f) grinding and sieving. Preparation of a water-swellable hydrophilic polymer (I) involves: (a) radical (co)polymerization of one or more hydrophilic monomer(s) (II), or graft (co)polymerization of one or more (II) onto a substrate (III), where the average degree of neutralization of the monomers containing acid groups is 0-40 mol. %, (b) comminuting the acid hydrogel, (c) post-neutralizing to a final neutralization degree of 60-85 mol. % in a shredder of a system having a screw, rotating knives, damming zones and perforated disks, operating at an output of 1000-6000 Wh/m , energy dissipation density 400-800 W/l, dwell time 5-30 s and free hole surface 20-40% of the perforated disk; (d) charging the neutralized hydrogel particles to a band drier, without application of further mechanical shear force; (e) drying the particles in the band drier; and (f) grinding and sieving the dried hydrogel particles.