It's probably a long shot but you could try reaching out to composite decking manufacturers to see what kind of plastics they are using. A lot of plumbing is done with plastics these days as well. Rope is made of plastic as well.

You might check your suppliers as too. You know they use polycarbonate, acrylic and so on for their manufacturing process.



The basic idea would be to locate someone that uses your kind of plastic as feed stock for their manufacturing process. Maybe try to work a deal where it goes directly from your company to theirs. You don't have to handle it ... just get a one or two percent cut on the deal as a facilitator's commission.