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US 12,649,115 B2Granted
Reducing surface and bulk contamination in plastic
AssigneeThe Procter & Gamble Company
InventorsNorman Scott Broyles, Dimitris Ioannis Collias, Anthony Frederick Cappel
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Abstract
The present invention generally relates to a method of reducing contamination from plastics. The resulting purer plastic can be used in demanding applications.
Claims14
A method to extract contaminates from a first plastic to produce a purer plastic comprising:
- a. providing a first plastic comprising individual contaminants, each individual contaminant having a concentration;
- b. extracting said individual contaminates from said first plastic at a temperature and a pressure, using a solvent that comprises an organic solvent or mixture of organic solvents, in extraction stages, wherein the total extraction time is less than about 6 hours, to produce a purer plastic comprising individual contaminates, each having a concentration;
- wherein said extraction stages are conducted at a solvent to first plastic mass ratio;
- wherein said solvent to first plastic mass ratio per stage at any time is less than 100:1;
- wherein said pressure is less than about 1,000 atm;
- wherein said first plastic individual contaminants comprise at least one of 4-tertpentylphenol, bisphenol A, OCDD, PCB 118, and 2-ethylhexyl phthalate;
- wherein at least one of the individual contaminants concentration in said purer plastic is reduced compared to its concentration in said first plastic by at least about 55% or LOQ;
- and
- wherein the solvent should not significantly dissolve the first plastic at the temperature and pressure of the process;
- and
- wherein the first plastic is a polyolefin.
8 more elements
Dependencies are inferred from the claim text.