Method for the pneumatic delivery of superabsorbent particles

{
  "publication_number": "US11859059B2",
  "country": "US",
  "kind": "B2",
  "title": "Method for the pneumatic delivery of superabsorbent particles",
  "abstract": "A method of pneumatically conveying superabsorbent particles, wherein the superabsorbent particles have been admixed with an aqueous wax dispersion prior to the pneumatic conveying, the wax has a glass transition temperature of at least 65° C. and, based on the untreated superabsorbent particles, from 0.020% to 0.20% by weight of wax has been used.",
  "claims": [
    "1. A method of pneumatically conveying superabsorbent particles comprising admixing the superabsorbent particles with an aqueous wax dispersion prior to pneumatic conveying, wherein the wax has a glass transition temperature of at least 65° C. and, based on the untreated superabsorbent particles, from 0.020% to 0.20% by weight of wax is admixed.",
    "2. The method according to claim 1, wherein the wax has a glass transition temperature of at least 80° C.",
    "3. The method according to claim 1, wherein, based on the superabsorbent particles, from 0.035% to 0.08% by weight of wax is admixed.",
    "4. The method according to claim 1, wherein the wax is a copolymer of 70 to 95 mol % of at least one ethylenically unsaturated hydrocarbon and 5 to 30 mol % of at least one ethylenically unsaturated carboxylic acid.",
    "5. The method according to claim 1, wherein the superabsorbent particles have an average particle size of 250 to 500 μm.",
    "6. The method according to claim 1, wherein the superabsorbent particles have an average sphericity (ASPHT) of greater than 0.72.",
    "7. The method according to claim 1, wherein a temperature of the superabsorbent particles during the pneumatic conveying is at least 40° C., and at least 20° C. less than the glass transition temperature of the wax.",
    "8. The method according to claim 1, wherein an initial gas velocity in the pneumatic conveying corresponds to a Froude number of 2 to 40.",
    "9. The method according to claim 1, wherein a conveying material load in the pneumatic conveying is from 1 to 30 kg/kg and the conveying material load is the quotient of conveying material mass flow rate and gas mass flow rate.",
    "10. A composition comprising superabsorbent particles and wax particles, wherein the wax particles are on the surface of the superabsorbent particles, the wax particles are dispersible in water and have a glass transition temperature of at least 65° C., a proportion of the wax particles based on the superabsorbent particles is from 0.02% to 0.2% by weight, and the composition has an absorption under a pressure of 4.83 kPa (AUL0.7 psi) of at least 10 g/g.",
    "11. The composition according to claim 10, wherein the wax has a glass transition temperature of at least 80° C.",
    "12. The composition according to claim 10, wherein, based on the superabsorbent particles, the proportion of wax particles is from 0.035% to 0.08% by weight of wax.",
    "13. The composition according to claim 10, wherein the wax is a copolymer of 5 to 30 mol % of at least one ethylenically unsaturated carboxylic acid and 70 to 95 mol % of at least one ethylenically unsaturated hydrocarbon.",
    "14. The composition according to claim 10, wherein the superabsorbent particles have an average particle size of 250 to 500 μm.",
    "15. The composition according to claim 10, wherein the superabsorbent particles have an average sphericity (ASPHT) of greater than 0.72."
  ],
  "description_excerpt": "The present invention relates to a method of pneumatically conveying superabsorbent particles, wherein the superabsorbent particles have been admixed with an aqueous wax dispersion prior to the pneumatic conveying, the wax has a glass transition temperature of at least 65° C. and, based on the untreated superabsorbent particles, from 0.020% to 0.20% by weight of wax has been used.\n\nSuperabsorbents are used to produce diapers, tampons, sanitary napkins and other hygiene articles, but also as water-retaining agents in market gardening. Superabsorbents are also referred to as water-absorbing polymers.\n\nThe production of superabsorbents is described in the monograph “Modern Superabsorbent Polymer Technology”, F. L. Buchholz and A. T. Graham, Wiley-VCH, 1998, pages 71 to 103.\n\nThe coating of superabsorbents with waxes is described, for example, in EP 0 755 964 A2 and WO 2008/077779 A1.\n\nIt was an object of the present invention to provide improved superabsorbents, especially superabsorbents having improved transport properties in the case of pneumatic conveying.\n\nThe object was achieved by a method of pneumatically conveying superabsorbent particles, wherein the superabsorbent particles have been admixed with an aqueous wax dispersion prior to the pneumatic conveying, the wax has a glass transition temperature of at least 65° C. and, based on the untreated superabsorbent particles, from 0.020% to 0.20% by weight of wax has been used.\n\nIn principle, there are three distinct types of pneumatic conveying:",
  "cpc": [
    "C08J 3/124",
    "A61L 15/60",
    "B65G 2201/042",
    "B65G 2812/1641",
    "B65G 53/04",
    "B65G 53/10",
    "C08J 2391/06",
    "C08J 3/126",
    "C08L 23/0869"
  ],
  "ipc": [
    "A61L 15/60",
    "B65G 53/10",
    "C08J 3/12",
    "C08L 23/08"
  ],
  "assignees": [
    "BASF SE"
  ],
  "inventors": [
    "Stephan Bauer",
    "Katrin Baumann",
    "Markus Toennessen",
    "Thomas Daniel",
    "Hanno Rüdiger Wolf"
  ],
  "filing_date": "2019-01-28",
  "publication_date": "2024-01-02",
  "grant_date": "2024-01-02",
  "priority_date": "2018-02-06",
  "application_number": "US-201916962659-A",
  "family_id": "61167981",
  "cited_by_count": 1,
  "citations": [
    "EP0755964A2",
    "US5840321A",
    "WO2006069732A1",
    "WO2008077779A1"
  ]
}