Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
  • A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
  • A61L15/42—Use of materials characterised by their function or physical properties
  • A61L15/60—Liquid-swellable gel-forming materials, e.g. super-absorbents

Definitions

• EP-A-0161762 relates to a water swellable, water insoluble polymer produced by inverse suspension polymerisation of a diallylic ammonium salt monomer, an acrylic monomer and a cross-linking agent.
• the product is an acrylic acid polymer containing both cationic and anionic groups in the chain which is intended for use as a superabsorbent in salt form. It is claimed that the material can absorb the same quantity of water irrespective of the salt content of the water but absorption is at a low level and the material does not show any significant improvement in its water absorption in the presence of salt as compared to conventional superabsorbents.
• the anionic superabsorbent preferably has 50 to 100% and more preferably has substantially 100% of the functional groups in free acid form.
• the cationic superabsorbent preferably has 50 to 100% and more preferably has substantially 100% of the functional groups in basic form.
• Starch and cellulose based polymers can also be used including hydroxypropyl cellulose, carboxymethyl cellulose and acrylic grafted starches.
• Particular base polymers include cross-linked polyacrylates, hydrolysed acryloni rile grafted starch, starch polyacrylates, and isobutylene maleic anhydride copolymers.
• Particularly preferred base polymers are starch polyacrylates and cross-linked polyacrylates.
• the functional groups will generally be carboxyl grou DS .
• the anionic superabsorbent may be directly synthesized in acid form by the radical polymerization of the acrylic acid monomer with a crosslinking agent, namely in the same manner as commercially available superabsorbents are synthesized.
• the cationic superabsorbent can also be a material formed from a polysaccharide based polymer as described above for the anionic superabsorbent but with cationic functional groups.
• the cationic superabsorbent may be based on a polymer of units of a monomer of formula (I) :
• cationic superabsorbents used according to the present inventions are resistant to hydrolysis at low alkaline pH and thus are not subject to the problems with release of toxic hydrolysis products referred to above in the context of the acrylamide derivatives suggested by WO 92/20735.
• suitable cationic functional groups include primary, secondary or tertiary amine groups or quaternary ammonium groups which should be present in base form. Preferably quaternary ammonium groups are used.
• Preferred base polymers include pblysaccharides and polymers based on dimethyldiallyl ammonium chloride.
• the cationic superabsorbent can be a polysaccharide superabsorbent obtained by reacting a fibrous polysaccharide such as cellulose with an excess of a quaternary ammonium compound containing at least one group capable of reacting with polysaccharide hydroxyl groups and having a degree of substitution of 0.5 to 1.1.
• the quaternary ammonium compound may have the general formula:
• n is an integer from l to 16;
• X is halogen;
• Z is an anion such as halide or hydroxyl; and
• R, R 1 , R 2 and R 3 which may be the same or different, are each hydrogen, alkyl, hydroxyalkyl, alkenyl or aryl and R 2 may additionally represent a residue of formula
• the cationic superabsorbent may be a water-swellable, water-insoluble polymer comprising units derived from a diallylic quaternary ammonium salt monomer, cross-linked by a suitable polyfunctional vinyl compound, characterised in that the polymer has been produced by cationic polymerisation in an aqueous phase using a free radical catalyst.
• a suitable polyfunctional vinyl compound characterised in that the polymer has been produced by cationic polymerisation in an aqueous phase using a free radical catalyst.
• the ratio of anionic to cationic superabsorbent is in the range 3:1 to 1:5 based on monomer units, more preferably 2:1 to 1:2, each monomer unit having one functional group therein.
• the anionic and cationic superabsorbents are used such that they have equal exchange power so that pH extremes in the bodily fluids absorbed are not reached and the optimum desalting effect is achieved.
• Cationic and anionic exchange power of the superabsorbent may be experimentally determined by, for example, titration, or in the case of synthetic polymers by a therotical calculation.
• the crosslinker solution and the radical initiator solution were added to the monomer solution, the temperature was adjusted to 60 ⁇ C by placing the flask in a thermostatic bath for four hours.
• samples A to D were put into a saline solution (1%) or solution of synthetic urine and into deionized water.

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• 1994
  • 1994-12-06 IT IT94TO000991A patent/IT1267184B1/it active IP Right Grant
• 1995
  • 1995-11-21 HU HU9800670A patent/HUT77680A/hu unknown
  • 1995-11-21 JP JP8517612A patent/JPH10509915A/ja active Pending
  • 1995-11-21 EP EP95940778A patent/EP0796144A4/de not_active Withdrawn
  • 1995-11-21 BR BR9509864A patent/BR9509864A/pt not_active Application Discontinuation
  • 1995-11-21 WO PCT/US1995/015139 patent/WO1996017681A1/en not_active Application Discontinuation
  • 1995-11-21 AU AU42417/96A patent/AU4241796A/en not_active Abandoned
  • 1995-11-21 CA CA002207081A patent/CA2207081C/en not_active Expired - Fee Related
  • 1995-11-21 CN CN95197333A patent/CN1173146A/zh active Pending
  • 1995-11-21 CZ CZ971699A patent/CZ169997A3/cs unknown
• 1997
  • 1997-06-04 NO NO972549A patent/NO972549L/no not_active Application Discontinuation
  • 1997-06-05 FI FI972385A patent/FI972385A/fi unknown

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Non-Patent Citations (1)

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