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US3770669A Expired / Lapsed US ⏱️ 0.0 years remaining

Process for the manufacture of cellular plastics from polyamides

Assignee: Hoechst AG
•
Filing: 1972-04-14
•
Granted: 1973-11-06
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Expires: 1992-04-14
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Abstract

Abstract THERE IS DISCLOSED AND CLAIMED A PROCESS FOR THE PRODUCTION OF CELLULAR PLASTICS FROM POLYAMIDES, WHICH EXHIBIT MELTING RANGES NEAR TO OR ABOVE THEIR DECOMPOSITION TEMPERATURES OR POOR OR NO SOLUBILITY AT ALL IN SOLVENTS OR WHICH EXHIBIT BOTH OF THESE PROPERTIES AT THE SAME TIME, THE PROCESS WHICH COMPRISES PROCESSING POLYAMIDES CARRYING SUBSTITUENTS AT THE AMIDE NITROGEN, FROM THE MELT OR FROM THE SOLUTION AND SPLITTING-OFF PARTIALLY OR TOTALLY THE N-SUBSTITUENTS TO YIELD CELLULAR PLASTICS BY THE FOAMING ACTION OF THE UNSATURATED COMPOUNDS WHICH ORIGINATE FROM THE N-SUBSTITUENTS DURING THE SPLITTING-OFF PROCESS. THIS FOAMING ACTION IS AUGMENTED BY ADDITIONALLY USING FOAMING OR EXPANDING AGENTS AND/OR REDUCING THE PRESSURE DURING THE SPLITTING-OFF PROCESS.

Inventors

  • 👤 L Brinkmann
  • 👤 W Herwig
  • 👤 E Reske
  • 👤 H Cherdron

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-03 19:31
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/04; C08G; C08G69/00; C08G69/48; C08J9/02; C08J2377/00

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) 1976-11-05 1977-05-07 1977-11-06 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1980-11-05 1981-05-07 1981-11-06 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1984-11-05 1985-05-07 1985-11-06 $7700.00 Window Closed / Lapsed

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