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US3621764A Expired / Lapsed US ⏱️ 0.0 years remaining

Method for making filtering material for tobacco products

Assignee: Individual
•
Filing: 1970-04-28
•
Granted: 1971-11-23
•
Expires: 1990-04-28
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Abstract

Abstract Method for treating paper to render it particularly adapted to be gathered and enclosed in a wrapper to make a filter cord subdividable into efficient cigarette filters. The paper is first moistened with a volatile, impregnating agent to prevent undue tearing in a longitudinal grooving and lateral stretching treatment which loosens and exposes fibers by passage through the nip between heated meshing rollers having alternating circumferential ribs and grooves. The impregnating agent has a boiling point and heat of evaporation less than those of water to reduce drying time. Coating materials, e.g. cellulose triacetate, cellulose acrylic acetate, may be dissolved in the impregnating agent so that the fibers of the paper will be coated with the material on evaporation of the impregnating agent.

Inventors

  • 👤 Paul A Muller
  • 👤 Hans Muster

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-03 13:03
CPC Classifications
A; A24; A24D; A24D3/00; A24D3/02; A24D3/0204; Y; Y10; Y10T; Y10T156/00; Y10T156/10; Y10T156/1002; Y10T156/1007; Y10T156/1016

Claims Analysis

Total Claims: 0
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References Cited (Backward Citations)

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USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1974-11-22 1975-05-24 1975-11-23 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1978-11-22 1979-05-24 1979-11-23 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1982-11-22 1983-05-24 1983-11-23 $7700.00 Window Closed / Lapsed

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