Process for the manufacture of fine-crystalline fluorescent brighteners of the bis-triazinylaminostilbene series in the .beta.-crystal form

Granted: Apr 27, 1982 Filed: Jul 13, 1979

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.