Polyvinyl chloride-polyethylene terephthalate separation process and product
OwnerRonald W. Koblerinventor
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Abstract
A hydrophobic polyvinyl chloride chip composition is described which has a preferred affinity for air when in water. The chip is supernatant in water after contact with air and has a skin layer containing a surface conditioning agent. A method for separating a PET/PVC chip admixture is also disclosed. The chip admixture is contacted with a surface conditioning agent to produce relatively hydrophobic polyvinyl chloride chips which can be floated in an aerated aqueous medium. The polyethylene terephthalate chips are recovered from the bottom of the aqueous medium. The flotation can be conducted in pure water without frothing or densifying agents.
Claims10
A process for separating polyvinyl chloride chips from polyethylene terephthalate chips, which comprises:
- conditioning a chip admixture constituted by polyethylene terephthalate chips and polyvinyl chloride chips having polyvinyl chloride polymer matrices that define external surfaces, with a surface conditioning agent that is selectively soluble in the polyvinyl chloride polymer matrices and renders the surfaces of the contacted polyvinyl chloride chips relatively more hydrophobic, said surface conditioning agent comprises one agent selected from the group consisting of diesters of aliphatic dicarboxylic acids, diesters of aromatic dicarboxylic acids, polyol polybenzoates, and trialkyl phosphate, said contacting being continued for a time period sufficient to cause the conditioning agent to penetrate the polyvinyl chloride chips and to produce a treated chip admixture;
- aerating the conditioned chip admixture while the conditioned chip admixture is in an aqueous medium having a surface tension not less than that of water, so as to contact air bubbles with the treated chip admixture;
- said air bubbles being of sufficient size to impart buoyancy to the air bubble contact polyvinyl chloride chips;
- and
- thereafter recovering polyvinyl chloride chips from the surface of the aqueous medium.
Dependencies are inferred from the claim text.