Hollow monofilament of high-loading capacity and method of making same

{
  "publication_number": "US3630824A",
  "country": "US",
  "kind": "A",
  "title": "Hollow monofilament of high-loading capacity and method of making same",
  "abstract": "Process for producing an industrial monofilament of a fiberforming thermoplastic polymer in which the polymer is melt spun as a hollow filament into an aqueous bath and withdrawn therefrom through a hot air zone while stretching in both the bath and the hot air zone to reduce the hollow cross section to less than 15 percent and especially less than 3 percent of the total cross section. The resulting monofilaments with a relatively fine hollow channel and outer diameters between about 0.8 and 8 mm. are useful for making nets, ropes, fishing lines and the like.",
  "claims": [
    "2. A monofilament as claimed in claim 1 wherein said hollow cross section occupies about 0.5 to 10 percent of the total cross section of the monofilament.",
    "3. A monofilament as claimed in claim 1 wherein said hollow cross section occupies less than 3 percent of the total cross section of the monofilament.",
    "4. A monofilament as claimed in claim 1 composed of polypropylene.",
    "5. A monofilament as claimed in claim 1 composed of nylon.",
    "6. A monofilament as claimed in claim 1 having a substantially circular cross section.",
    "7. A process for the production of an industrial monofilament of a synthetic, fiber-forming, linear thermoplastic polymer which comprises: melt-spinning a hollow monofilament of said polymer by extrusion through an annular opening around one end of a coaxial and concentric small hollow tube which is in fluid communication with the outside atmosphere at its opposite end; withdrawing the spun hollow monofilament through an aqueous cooling bath for solidification of the polymer while imparting a first stretch sufficient to partly reduce the inner and outer diameter of the monofilament; and further withdrawing the solidified and partly stretched monofilament through a hot air zone while imparting a second stretch, the size of the initially spun monofilament and the amount of stretching imparted thereto being sufficient to reduce the outer diameter to about 0.8 to 8 mm. and the inner diameter to a value of about 0.1 to 15 percent of the outer diameter.",
    "8. A process as claimed in claim 7 wherein the spun hollow monofilament is stretched sufficiently to reduce the inner diameter to a value of less than 3 percent of the outer diameter.",
    "9. A process as claimed in claim 7 wherein the thermoplastic polymer is polypropylene.",
    "10. A process as claimed in claim 7 wherein the thermoplastic polymer is nylon."
  ],
  "cpc": [
    "D01D 5/24",
    "Y10T 428/2975",
    "Y10T 428/31739",
    "Y10T 428/31938"
  ],
  "assignees": [
    "BARMAG BARMER MASCHF"
  ],
  "filing_date": "1969-05-19",
  "publication_date": "1971-12-28",
  "grant_date": "1971-12-28",
  "priority_date": "1968-05-22",
  "application_number": "US-3630824D-A",
  "family_id": "5696101",
  "citations": [
    "US3095258A",
    "US3160193A",
    "US3389548A",
    "US3452130A",
    "US3507948A"
  ]
}