US Patent 7452592 - Biopolymer nanoparticle oxygen barrier

http://www.freepatentsonline.com/7452592.html

This patent from Innovia Films teaches food packaging serving as an oxygen barrier which can be made cheaper and more ecologically efficient via the use of biopolymer nanoparticles. Claim 1 reads:

1. A substantially planar self-supporting sheet comprising on at least one side thereof a substantially continuous adherent coating thereon to create a barrier to oxygen, the coating comprising biopolymer nanoparticles in an amount of at least 20% by dry weight of the coating, forming a substantially continuous phase on the sheet, said biopolymer nanoparticles obtained from a mechanical thermoplastic process comprising a cross-linking step using a cross-linking agent.