Process for producing superabsorbents

• Main Authors: Herfert, Norbert, Poomsuwan, Wanthip, Gieger, Thomas
• Format: Patent
• Language: English
• Published: 12.03.2019
• Subjects: ADHESIVES; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS, ORSURGICAL ARTICLES; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMICAL PAINT OR INK REMOVERS; CHEMISTRY; COATING COMPOSITIONS, e.g. PAINTS, VARNISHES ORLACQUERS; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; CORRECTING FLUIDS; DISINFECTION, STERILISATION, OR DEODORISATION OF AIR; DYES; FILLING PASTES; GENERAL PROCESSES OF COMPOUNDING; HUMAN NECESSITIES; HYGIENE; INKS; MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVINGCARBON-TO-CARBON UNSATURATED BONDS; MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONSONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS, OR SURGICALARTICLES; MEDICAL OR VETERINARY SCIENCE; METALLURGY; METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS INGENERAL; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; ORGANIC MACROMOLECULAR COMPOUNDS; PAINTS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; POLISHES; THEIR PREPARATION OR CHEMICAL WORKING-UP; THEIR RELEVANT APPARATUS; TRANSPORTING; USE OF MATERIALS THEREFOR; WOODSTAINS; WORKING-UP

The invention relates to a process for producing superabsorbents, comprising the preparation of partly neutralized acrylic acid by the steps (i) preparing an over-neutralized acrylic acid having a degree of neutralization of at least 100.1 mol-% by mixing of an acrylic acid 1 and a base and (ii) preparing a neutralized acrylic acid having a degree of neutralization from 50 to 85 mol-% by mixing of the over-neutralized acrylic acid and an acrylic acid 2, wherein the content of dimeric acrylic acid in the acrylic acid 2 is lower than the content of dimeric acrylic acid in the acrylic acid 1.