Method of applying an impact resistant moisture impermeable resinous coating

{
  "publication_number": "US4752497A",
  "country": "US",
  "kind": "A",
  "title": "Method of applying an impact resistant moisture impermeable resinous coating",
  "abstract": "A method of forming an impact-resistant, moisture impermeable coating on the surface of an object, such as a pipe, comprises heating the object to a temperature above which a thermosetting resin applied to the heated surface will fuse, so that the resin forms a continuous layer. Before the layer of resin has gelled, a second layer consisting of a finely divided particulate mixture of the resin and a solid such as glass fiber or mica is applied over the first layer. The two layers are fused together to form a homogeneous resin covering with one layer reinforced by the above solid. The resin coating is then cured and the object allowed to cool. An apparatus for carrying out the method is also described.",
  "claims": [
    "1. A method of forming an impact resistant moisture impermeable resinous coating on the surface of a metallic object which comprises applying a thermosetting resin onto said surface, the surface having been heated to a temperature above the fusion temperature of the resin, the resin being fused thereon to form a first continuous layer, applying onto said layer before it has gelled a finely divided mixture consisting of said resin and a particulate inorganic solid selected from the group consisting of glass fibres and mica flakes to form a second continuous layer covering the first layer, the layers fusing together to form a homogeneous resin covering with the particulate solid reinforcing the second layer, and cooling and curing the applied resin.",
    "2. A method according to claim 1, wherein the resin of said first and second layers is applied in powdered form.",
    "3. A method according to claim 2, wherein the resin of said first layer and said finely divided mixture are applied by electrostatic spraying.",
    "4. A method according to claim 1, wherein the metallic object is a cylindrical pipe, the pipe being rotated continuously about its axis during said application, cooling and curing steps.",
    "5. A method according to claim 1, wherein the resin is an epoxy resin."
  ],
  "description_excerpt": "This invention relates to the coating of metal objects with powdered resinous materials. More particularly, it relates to the coating of steel pipes and pipe sections with powdered thermosetting resins, such as epoxy resins, although it is to be understood that the invention is applicable also to the coating of other metallic objects such as reinforcing bars to be used in concrete reinforcement.\n\nThe provision of thermally and/or electrically insulating coatings of epoxy resins on steel pipe sections, for example, which are intended to be used to form fluid conducting pipelines, either above or below the ground, is known. Customarily, the process involves the spraying of the epoxy resin in powder form onto steel pipe electrostatically. After abrasive cleaning of the pipe surface, e.g. by shot blasting, the metal pipe is heated, given an electrical charge, and epoxy resin powder charged oppositely to the pipe is applied to the pipe by spraying, so that the powder adheres electrostatically to the pipe surface. The coating cures on the hot pipe thereon. The epoxy resin powder which does not adhere to the pipe surface after spraying is collected and returned to the epoxy powder storage hopper to be recycled. One electrostatic powder coating process of this type is described in U.S. Pat. No. 3,904,346 dated Sept. 9, 1975.",
  "cpc": [
    "B05D 7/146",
    "B05D 1/00",
    "B05D 5/02",
    "F16L 58/1072"
  ],
  "ipc": [
    "B05D 5/00",
    "B05D 5/02",
    "B05D 7/14",
    "F16L 58/10"
  ],
  "assignees": [
    "Shawcor Ltd"
  ],
  "inventors": [
    "Stephen E. McConkey",
    "Gordon G. Macphail"
  ],
  "filing_date": "1986-05-29",
  "publication_date": "1988-06-21",
  "grant_date": "1988-06-21",
  "priority_date": "1983-08-25",
  "application_number": "US-86805686-A",
  "family_id": "10547858",
  "cited_by_count": 39,
  "citations": [
    "US3177902A",
    "US3208868A",
    "US3490934A",
    "US3708321A",
    "US3904346A",
    "SU502660A1",
    "US4142555A",
    "US4138516A",
    "US4158371A",
    "US4405727A"
  ]
}