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Process of etching metal with ammonium persulfate with recovery and recycling

US 3,671,344 A · Inventors: CHIANG JOHN S C et al.

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Listed from its USPTO record in Patent Yard's full-term archive. Its claims, description and drawings are in the USPTO PDF and on Google Patents, and the Claude kit works from them.

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Why it's free to use

  • Granted June 20, 1972. A patent granted before 1976 lasted at most 17 years from grant, so its term ended by June 20, 1989.
  • We check US rights only. Old patents can still inspire new ones: improvements may be patentable.
FiledDecember 4, 1970
GrantedJune 20, 1972
Term endedJune 20, 1989
Application number—
Classification (CPC)C23F1/18
Length4 pages

Timeline

Timeline From USPTO dates

1971197319751977197919811983198519871989Application filedDec 4, 1970Patent grantedJune 20, 1972Term endedJune 20, 1989

Sources & verification

Official USPTO records

Full published documentText and every drawing sheet as a PDF.USPTOFile historyStatus, office actions, notices, fee records and petitions.USPTO Patent CenterPatent Public Search recordSearchable full text and bibliographic data.USPTO

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