Particulate thickening agent

{
  "publication_number": "US4097405A",
  "country": "US",
  "kind": "A",
  "title": "Particulate thickening agent",
  "abstract": "An effective thickening agent comprises particulate matter of less than 425 microns when said particulate matter comprises silica particles bonded to an acrylic polymer capable of hydrogen bonding.",
  "claims": [
    "1. A thickener comprising particulate matter of less than 425 microns, said particulate matter comprising silica particles of from 7 × 10 -3 to 6 μ bonded to an acrylic polymeric material comprising on a dry basis, from 14 to 40% by weight of said particulate matter and capable of hydrogen bonding and being sufficiently hydrophilic to be dispersible in water or other aqueous liquids, said silica having a large surface area and being capable of aggregating because of hydrogen bonding when dispersed in water.",
    "2. The thickener of claim 1 which is further characterized by being a dry powder with less than 16% by weight water content.",
    "3. A thickener comprising particulate matter of less than 425 microns, said particulate matter comprising silica particles of from 7 × 10 -3 to 6 μ bonded to an acrylic polymeric material which (1) comprises on a dry basis, from 14 to 40% by weight of said particulate matter, (2) is capable of hydrogen bonding, and (3) being sufficiently hydrophilic to be dispersible in water, said silica having a large surface area and being capable of aggregating because of hydrogen bonding when dispersed in water, said acrylic polymeric material comprising a copolymer of at least one acid selected from the group consisting of acrylic and methacrylic acid with at least one comonomer selected from the group consisting of lower alkyl acrylates and lower alkyl methacrylates.",
    "4. The thickener of claim 3 wherein said lower alkyl acrylates and methacrylates are selected from the group consisting of methyl and ethyl acrylates and methacrylates.",
    "5. The thickener of claim 3 which is further characterized by being a dry powder with less than 16% by weight water content.",
    "6. The thickener of claim 4 which is further characterized by being a dry powder with less than 16% by weight water content.",
    "7. The thickener of claim 3 in which the average particle size of said particulate matter is less than 150 microns.",
    "8. The thickener of claim 4 in which the average particle size of said particulate matter is less than 150 microns.",
    "9. The thickener of claim 3 in which said silica particles and said acrylic polymeric material were codried, said acrylic polymeric material being derived from an aqueous latex.",
    "10. The thickener of claim 4 in which said silica particles and said acrylic polymeric material were codried, said acrylic polymeric material being derived from an aqueous latex."
  ],
  "description_excerpt": "This invention relates to thickeners and in particular thickeners which can be provided in a dry solid form and which will readily disperse in liquids such as aqueous or polar liquids, to thicken them particularly when the liquids have neutral or alkaline pH values.\n\nMany thickeners are known for addition to aqueous liquids but they have various disadvantages, particularly in that some cannot readily be dispersed in aqueous liquids and others cannot readily be supplied in a dry powder form for later dispersion into an aqueous liquid.\n\nAccording to the invention there is provided a finely divided dry powder thickener comprising a finely divided silica which has a large surface area and which is itself capable of aggregating because of hydrogen bonding when dispersed in a liquid, and bonded to the silica a dried aqueous acrylic polymer latex, the acrylic polymer itself being capable of thickening and having some hydrophilic groups and other groups which are capable of forming hydrogen bonds with the silica, and the polymer being in a form which is readily dispersible in water or other aqueous liquids.\n\nSuch a thickener will very effectively thicken polar liquid compositions, e.g. water-based compositions, and has the important advantage that, after it has been dried and powdered, it can readily be dispersed in water-based compositions to thicken them. The thickners of the invention can therefore usefully be incorporated into dry solids powder compositions which have later to be dispersed or dissolved in water or other polar solvents. They can, for example, usefully be incorporated into hair bleaching compositions.",
  "cpc": [
    "A61Q 5/08",
    "A61K 47/32",
    "A61K 8/25",
    "A61K 8/8152",
    "C08K 3/36",
    "Y10T 428/2993"
  ],
  "ipc": [
    "A61K 47/32",
    "A61K 8/25",
    "A61K 8/81",
    "A61Q 5/08",
    "C08K 3/36"
  ],
  "assignees": [
    "Minnesota Mining and Manufacturing Co"
  ],
  "inventors": [
    "Ronald E. Watts"
  ],
  "filing_date": "1976-07-08",
  "publication_date": "1978-06-27",
  "grant_date": "1978-06-27",
  "priority_date": "1975-07-14",
  "application_number": "US-70336376-A",
  "family_id": "10292376",
  "cited_by_count": 22,
  "citations": [
    "US3061577A",
    "US3287290A",
    "US3131148A",
    "US3679382A",
    "US3962267A"
  ]
}