公开(公告)号：DE602004018761D1

公开(公告)日：2009-02-12

申请号：DE602004018761

申请日：2004-03-20

Applicant: BASF SE

Inventor： BENNETT ANDREA KAREN ,  MITCHELL MICHAEL A ,  CARRICO PETER W

IPC: B01D61/14 ,  A61L15/60 ,  B01D61/02 ,  B01D61/04 ,  B01D61/16 ,  B01D63/16 ,  C08F6/06 ,  C08F6/12 ,  C08F8/12 ,  C08J3/03 ,  C08L39/02

Abstract: Process for reducing the content of water-soluble salts of aqueous solutions of polymers containing vinylamine groups by ultrafiltration to achieve a residual salt content of 1 to 10% by weight based on total solution solids in the polymer solution comprising feeding an aqueous salt-containing solution of vinylamine group containing polymers at a polymer concentration of at least 7% by weight to an ultrafiltration unit and removing the water-soluble salts with the permeate from the feed solution by adding thereto less than 4 parts by weight of water per one part by weight of the feed solution, and use of the polymer of the aqueous solutions thus purified as basic water-absorbing resin of multicomponent superabsorbent polymers. Preferably vibratory shear membranes in a diafiltration configuration are used.

公开(公告)号：BRPI0814746A2

公开(公告)日：2015-03-03

申请号：BRPI0814746

申请日：2008-08-08

Applicant: BASF SE

Inventor： FUNK RUEDIGER ,  HEIDE WILFRIED ,  WEISMANTEL MATTHIAS ,  HAMMON ULRICH ,  BENNETT ANDREA KAREN

IPC: C08F2/00 ,  C08F20/06

Abstract: What is described is a process for producing water-absorbing resins, in which a) acrylic acid is prepared at an acrylic acid production site, b) the acrylic acid prepared is dissolved in water at the acrylic acid production site to obtain an aqueous acrylic acid solution, c) the aqueous acrylic acid solution is fed into a pipeline at the acrylic acid production site and passed through the pipeline to an acrylic acid processing site and d) the aqueous acrylic acid solution is subjected to a free-radical polymerization at the acrylic acid processing site. The process ensures safe transport of the highly reactive acrylic acid. Endangerment as a result of premature polymerization, as in the case of glacial acrylic acid, is ruled out, since the acrylic acid is “diluted” by the aqueous solvent and the specific heat capacity and the evaporation enthalpy of the water limit the maximum temperature rise. The amount of polymerization inhibitors used be reduced or it is possible to entirely dispense with polymerization inhibitors. Temperature control of vessels and pipelines within which the aqueous acrylic acid solution is conducted can be dispensed with because the solidification point of the aqueous acrylic acid solution is lower than that of anhydrous acrylic acid.