Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA898733A
Inventor
Okada Takashi
Miyata Kankichi
Ishikawa Toshikatsu
Endo Tei
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Carbon Co Ltd
Original Assignee
Nippon Carbon Co Ltd
Publication date
Application grantedgrantedCritical
Publication of CA898733ApublicationCriticalpatent/CA898733A/en