When working in the Assembly environment (*.iam), the File Properties command from PowerPack for Inventor allows you to export the properties as a *.txt file and edit / process them further (import in ERP, etc.).
The command can be found in the Toolbox panel.

File Properties command
After you have executed the command, a text file *.txt is automatically saved under: %localappdata%/Temp/Graitec and opened at the same time; the text file contains all properties of the opened Inventor file.
For the information structure, note that each property consists of three pieces of information separated by a hyphen:
Property (English) – Property (Inventor language) – Property value.
If a property is not filled in, there is no information under Value either, i.e. it is empty.