The polypropylene foam patent is for sale at a very reasonable price. Few companies in the United States have a patent for polypropylene foam, and a few are infringing on this technology.  The link below will give a complete description as listed with the United States Patent Office and offers a glimpse of the capabilities of the technology.  If you would like to purchase this patent  please contact Associated Polymer Labs:

United States Patent 6,946,495

Title: Foamable composition using recycled or offgrade polypropylene

Abstract: A polymeric composition to be used in producing foam in which the polymeric composition comprises conventional linear polypropylene, high melt strength polypropylene and a rheology modifier resin. The conventional linear polypropylene is in an amount of from about 1 to 25 weight percent of the polymeric composition. The high melt strength polypropylene is in the amount of from about 51 to 85 weight percent of the polymeric composition. The rheology modifier resin is in the amount of from 5 to about 30 weight percent of the polymeric composition. The conventional linear polypropylene may be offgrade virgin polypropylene or recycled polypropylene from post-industrial or post-consumer sources. The rheology modifier resin is a member of the group of styrene-olefin copolymers.

United States Patent Office Link:

http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=...

Costs: Make an offer, this patent is for sale.

Confidentiality: Associated Polymer Labs, Inc. respects our clients’ needs regarding business information security, and all information provided by the client shall be kept confidential.

Liability: Unless contrary to NYS law, Associated Polymer Labs, Inc. total liability shall be limited to replacement of, or refund of an amount that will not exceed the sales price of services rendered. In no case will Associated Polymer Labs, Inc. be liable for consequential or special damages even if Associated Polymer Labs, Inc. has been advised of the possibility of such damages.