METHOD FOR TREATING RECYCLED POLYETHYLENE TEREPHTHALATE FOR ACCELERATED PROCESSING

Abstract

A process for preparing a PET composition is provided. The process includes the steps of: providing an early stage VPET and an RPET; comminuting the RPET; and blending the RPET and the early stage VPET to form a VPET/RPET blend, wherein the blending occurs prior to a polycondensation reaction. A process is also described that includes the step of: adding the comminuted RPET to the early stage VPET before a polycondensation reaction process, wherein contaminants are caused to diffuse out of the comminuted RPET. In a further process, the comminuted RPET is decontaminated in a step separate from the blending to form the VPET/RPET blend.

Description

Claims

1. A process for preparing a PET composition, comprising the steps of: providing an early stage VPET;providing an RPET;comminuting the RPET; andblending the RPET and the early stage VPET to form a VPET/RPET blend, wherein the blending occurs prior to a polycondensation reaction.

2. The process of claim 1, further comprising the step of: solid-stating the VPET/RPET blend to form the PET composition having an intrinsic viscosity suitable for production of a PET article.

3. The process of claim 2, wherein the step of solid-stating the VPET/RPET blend includes: heating the VPET/RPET blend to a temperature below a melting point of the VPET/REPT blend, wherein a transesterification of the VPET/RPET blend occurs.

4. The process of claim 2, wherein the intrinsic viscosity of the PET composition following solid-stating is between about 0.72 dg/L and about 0.84 dg/L.

5. The process of claim 1, wherein the early stage VPET is provided by esterification of an ethylene glycol and a purified terepthalic acid.

6. The process of claim 1, wherein the early stage VPET has an intrinsic viscosity between about 0.01 dg/L and about 0.03 dg/L.

7. The process of claim 1, wherein the RPET is provided as RPET flakes.

8. The process of claim 1, wherein the comminuted RPET includes particles having an average particle size between about 0.01 mm and about 2.5 mm in diameter.

9. The process of claim 1, wherein the RPET has an intrinsic viscosity greater than about 0.8 dg/L.

10. The process of claim 8, wherein the RPET has an intrinsic viscosity between about 0.8 dg/L and about 0.95 dg/L.

11. The process of claim 1, wherein the VPET/RPET blend has a greater intrinsic viscosity than the early stage VPET.

12. The process of claim 1, further comprising the step of: decontaminating the comminuted RPET, wherein contaminants are caused to diffuse out of the RPET.

13. The process of claim 12, wherein the step of decontaminating the comminuted RPET includes heating the comminuted RPET, wherein a diffusion of the contaminants from the RPET is accelerated.

14. The process of claim 12, wherein the step of decontaminating the comminuted RPET includes introducing the comminuted RPET into the early stage VPET.

15. The process of claim 1, further comprising the step of: melting the comminuted RPET.

16. The process of claim 15, wherein the step of melting the comminuted RPET includes extrusion.

17. The process of claim 1, further comprising the step of: conducting at least one polycondensation reaction adapted to increase an intrinsic viscosity of the VPET/RPET blend.

18. The process of claim 1, further comprising the step of: filtering the VPET/RPET blend.

19. A process for preparing a PET composition, comprising the steps of: comminuting a quantity of RPET flakes to form RPET particles having an average particle size between about 0.01 mm and about 2.5 mm in diameter;adding the comminuted RPET to an early stage VPET before a polycondensation reaction process, wherein contaminants are caused to diffuse out of the comminuted RPET; andsolid-stating the VPET/RPET blend, thereby forming the PET composition.

20. A process for preparing a PET composition, comprising the steps of: providing an early stage VPET having an intrinsic viscosity between about 0.01 and about 0.03;providing an RPET having an intrinsic viscosity between about 0.8 and about 0.95;comminuting the RPET to form RPET particles having an average particle size between about 0.01 mm and about 2.5 mm in diameter;decontaminating the RPET particles;melting the decontaminated RPET particles to form an RPET melt;blending the RPET melt and the early stage VPET to form the VPET/RPET blend, wherein the intrinsic viscosity of the VPET/RPET blend is greater than the intrinsic viscosity of the early stage VPET;conducting at least one polycondensation reaction adapted to increase the intrinsic viscosity of the VPET/RPET blend; andsolid-stating the VPET/RPET blend to form the PET composition having an intrinsic viscosity between about 0.72 dg/L and about 0.84 dg/L.