Method for preparing extremely small particles of recycled polyethylene terephthalate
AssigneePhoenix Technologies International, LLC
InventorsDonald W. Hayward, Daniel L. Witham
Life of this patent
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Abstract
A process for preparing extremely small RPET particles comprises proving a quantity of RPET flakes, increasing the crystallinity of the RPET flakes, separating a portion of the RPET flakes having the lowest particle density from the remainder of the RPET flakes, and comminuting the remaining RPET flakes, to prepare RPET particles having an average mean particle size less than 500 microns.
Claims14
A process for preparing extremely small RPET particles, comprising the steps of:
- providing a quantity of RPET flakes;
- increasing the crystallinity of the RPET flakes;
- separating a portion of the RPET flakes having a lower particle density from the remainder of the RPET flakes;
- and
- comminuting the remaining RPET flakes, to prepare RPET particles having an average mean particle size less than about 500 microns.
A process for preparing extremely small RPET particles, comprising the steps of:
- providing a quantity of RPET flakes, comprising chunks, spheres, pellets, or mixtures thereof, having particle sizes from about ¼ inch to about ½ inch;
- increasing the crystallinity of the RPET flakes, by heating the RPET flakes to a temperature above the glass transition temperature of the polyethylene terephthalate from which the RPET flakes were derived;
- separating, by air elutriation, a portion of the RPET flakes having a lower particle density from the remainder of the RPET flakes;
- and
- comminuting, by impact fracturing, the remaining RPET flakes, to prepare RPET particles having an average mean particle size less than about 500 microns.
A process for preparing extremely small RPET particles, comprising the steps of:
- providing a quantity of RPET flakes, comprising chunks, spheres, pellets, or mixtures thereof, having particle sizes from about ¼ inch to about ½ inch;
- increasing the crystallinity of the RPET flakes, by heating the RPET flakes to a temperature greater than about 150° Celsius and maintaining the elevated temperature for a period of time ranging from about ten minutes to about twenty-four hours;
- separating, by air elutriation, a portion of the RPET flakes having a lower particle density from the-remainder of the RPET flakes;
- and
- comminuting, by impact fracturing, the remaining RPET flakes, to prepare RPET particles having an average mean particle size less than about 300 microns.
Dependencies are inferred from the claim text.