Granted Patent
Utility
US 5,204,039 · App. 07/797,056
Extrusion method and extruder used for obtaining phenolic resin pipe
Inventors:
Takeshi Miyasaka, Kunio Hanaue
Patented Case
View Patent ↗
Granted: Apr 20, 1993
Filed: Nov 25, 1991
Inventors
Takeshi Miyasaka
Kunio Hanaue
Assignee (at issue)
Mitsui Toatsu Chemicals, Incorporated
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.