The function of the silk mill was to spool silk thread. Very few full spools were left behind when the factory closed. I am not sure if the thread seen here is silk or synthetic. I've read that during the last years of production some synthetic threads was spooled.
The lot numbers and notes on this rack is intriguing. Equally interesting to me is the mystery of the manufacturing process of that occurred here. Beyond the rows and rows of machines used to spool the thread are drying chambers, large spinning tubs and documents describing material treatment recipes. Apparently the thread was treated with various chemicals by soaking for specified time and temperature as part of the manufacturing process.