Method for producing water-absorbent polymers

• Main Authors: VAN ESBROECK, DOMINICUS, WEISMANTEL, MATTHIAS, BRUHNS, STEFAN
• Format: Patent
• Language: English; French; German
• Published: 17.02.2016
• Subjects: AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; BLASTING; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS, ORSURGICAL ARTICLES; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMISTRY; COMPOSITIONS BASED THEREON; DISINFECTION, STERILISATION, OR DEODORISATION OF AIR; DRYING; DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM; GENERAL PROCESSES OF COMPOUNDING; HEATING; HUMAN NECESSITIES; HYGIENE; LIGHTING; MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVINGCARBON-TO-CARBON UNSATURATED BONDS; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS, OR SURGICALARTICLES; MECHANICAL ENGINEERING; MEDICAL OR VETERINARY SCIENCE; METALLURGY; METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS INGENERAL; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; THEIR PREPARATION OR CHEMICAL WORKING-UP; THEIR RELEVANT APPARATUS; TRANSPORTING; WEAPONS; WORKING-UP

Preparation of water-absorbing polymers (A) with drying quality index comprises polymerizing a monomer solution and drying the obtained hydrogel agent in hot-gas flow, where the drying process takes place in at least two temperature zones, when the flow of the hydrogel in the gas flow is: downwards in the front side of the volume drier, and upwards against the rear side of the drier; where the amount of water in the hydrogel is 15-45 wt.%, the hydrogel layer in the volume drier flows at least partially against down wards, and the speed of the gas is 5-30%. Preparation of water-absorbing polymers (A) with drying quality index comprises polymerizing a monomer solution and drying the obtained hydrogel agent in hot-gas flow, where the drying process takes place in at least two temperature zones, when the gas inlet temperature (T n) is not equal to T n + a; and flow of the hydrogel in the gas flow is: downwards in the front side of the volume drier, and upwards against the rear side of the drier; where the amount of water in the hydrogel is 15-45 wt.%, the hydrogel layer in the volume drier flows at least partially against down wards, and the speed of the gas is 5-30%. n : index; and a : greater than 0. An independent claim is included for a device for drying (A) comprising a gas permeable conveyer belt (which is streamed by a preheated gas), where the gas inlet temperature is adjusted such that it can come form at least two temperature zones.