Water absorbent and producing method of same

• Main Author: TORII KAZUSHI,SHIBATA HIROFUMI,IWAMURA TAKU,IRIE YOSHIO,DAIROKU YORIMICHI,MITSUKAMI YOSHIRO,MACHIDASAYAKA
• Format: Patent
• Language: English
• Published: 01.11.2006
• Subjects: AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; BANDAGES, DRESSINGS OR ABSORBENT PADS; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS, ORSURGICAL ARTICLES; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMISTRY; COMPOSITIONS BASED THEREON; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF,TUBULAR STRUCTURES OF THE BODY, E.G. STENTS; DISINFECTION, STERILISATION, OR DEODORISATION OF AIR; FILTERS IMPLANTABLE INTO BLOOD VESSELS; FIRST-AID KITS; FOMENTATION; GENERAL PROCESSES OF COMPOUNDING; HUMAN NECESSITIES; HYGIENE; MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVINGCARBON-TO-CARBON UNSATURATED BONDS; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS, OR SURGICALARTICLES; MEDICAL OR VETERINARY SCIENCE; METALLURGY; METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS INGENERAL; ORGANIC MACROMOLECULAR COMPOUNDS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; PROSTHESES; THEIR PREPARATION OR CHEMICAL WORKING-UP; THEIR RELEVANT APPARATUS; TRANSPORTING; TREATMENT OR PROTECTION OF EYES OR EARS; WORKING-UP

An object of the present invention is to provide a water absorbent having excellent gel properties and showing excellent properties when used in a water-absorbing material of a sanitary/hygienic material such as paper diaper. Moreover, another object of the present invention is to provide a water absorbent which is safe and excellent in liquid permeability, and in which an amount of liquid permeability improver for improving the liquid permeability is reduced. The water absorbent is made from a water-absorbing resin prepared by a specific polymerization method and having a high degree of cross-linking, a high liquid holding property and a high gel strength (its swelling pressure of gel layer of is 35 kdyne/cm2 or more). This water absorbent is further processed to have a particular particle size distribution (95wt% or more of its particles are less than 850f¿‘m but not less than 106f¿‘m, and logarithmic standard deviation (fDf) is in a range of 0.25 to 0.45) and then surface cross-linked. After that, a liquid permeability improver is added therein.