1. Post consumed Amosorb recycling work update
CME has acquired the facilities to run full in-house recycling protocols mimicking Petcore conditions (not washing)
Twin screw extruder
SSP unit
Standard Amosorb 4020 at 2% LDR would pass the Petcore protocol at 10% additive flake level
CME has consulted Professor Norman Allen for advice on ways of reducing discoloration of polyester resins
A number of different antioxidant chemistries were proposed to CME and are being investigated
Amosorb 100 at 2% ( version with a primary phenolic antioxidant) passes Petcore protocol at their required 12.5% level
We expect to further succeed in reducing PET discoloration with other antioxidants

2. Petcore Protocol

3. Thermal PET histories during recycling
Polymers exposed to high temperatures are prone to discoloration due to thermooxidative reactions in the presence of oxygen leading to discoloration
Thermal histories of PET during recycling:
PET dried for approximately 4-6 hours at 160 °C to remove moisture
First melt injection moulding into preforms at ° C
PET flakes are dried at 160 ° C for 4-6 hours prior to extrusion
PET melt extrusion into pellets at 280 ° C
Solid state polycondensation of PET pellets under nitrogen at ° C to increase molecular weight
Second melt injection moulding at 280 ° C into plaques

4. Polymer autoxidation Cycle

5. Inhibited Autoxidation Cycle

6. Mechanism of activity: Phenolic antioxidant as radical scavengers

7. Phenolic antioxidants: Stabilisation via free radicals scavenging

8. Termination of Phenolic antioxidants

9. Mechanism of activity: Phosphites as hydroperoxide decomposer

10. Decomposition of hydroperoxides
Co (ll)

11. Oxidation of Phosphites to phosphates

12. Mechanism of activity: Hindered Amines (free radical scavengers)

13. Hindered amines: Stabilisation via free radical scavenging mechanism

14. Other yellowing quenchers
UV stabiliser
Vitamins B,E,C
Lactones
Arylamines as primary antioxidants

15. Recyclability of Amosorb 100 versus Amosorb 4020 according to Petcore protocol
Amosorb 100 contains a primary phenolic antioxidant
Amosorb 100 would just pass the Petcore protocol colour specifications at a loading of 12.5%
The standard Amosorb 4020 grade will pass at 10 % loading

16. Further work to improve Amosorb recyclability
Evaluate other Phenolic primary antioxidants (Cycle 1)
Investigate beneficial effect of hydroperoxide scavengers such as Phosphites-HALS (Cycle 2)
Try synergistic mixtures of the above suggested by Norman Allen
Try other materials with known benefit on colour:
Vitamin B, E
UV absorbers
Others

17. Autoxidation of Polymers: Main sites for hydrogen abstractions