There may be information in the PA State Incorporation Divison of their incorporation.
You might also post in the AskPIP forums of SPE at http://www.askpip.org
You could post in both the theroset forum and the molders forum. You might also contact the Local SPE Section that includes Scranton,PA in their area.
Another source is the archive files of the Scranton newspaper. They may be available on line.
If they were a public company then Dun and Bradstreet (SP?) may have information on the sale or closure.
Contact the Plastics Pioneers they may know.
"If you want to soar with the Eagles in the morning.......
You can't hoot with us Owls all night"