Blow Moulding Process & Barrier Containers Part 2 Equipment

1. Blow Moulding Process & Barrier Containers Part 2 Equipment

2. Major process stages • Feeding system for the granules, regrind and masterbatches • Melting and homogenizing of the plastic in a single screw extruder • blowing of the bottle • cooling of the bottle • calibration and de-flashing • leak proof testing

3. Blow moulding techniques • Extrusion blow moulding • continuous extrusion • intermittent extrusion • Injection blow moulding • Injection stretch blow moulding

4. Extrusion Blow Moulding – Wheel Machines

5. Continuous extrusion blow moulding 1 Line with double station for Max. 24 cavities

6. Blow Moulding Machine

7. Blow Moulding Line Equipment elements • Feeding system (volumetric, gravimetric, mixing), hopper • Extruder: screw, barrel, adaptor • (Filter screen-pack, filter changer) • Head, parison control, die: mandrel, bushing • Parison cutter • Blow unit • Mould(s) • De-flashing unit • On-line test unit (holes, top-load) • Labelling (glueing, IML), printing (flaming, Corona)

8. Equipment set-up Die centeringadjustment bolts Die Blow pin Hot knife cutter Parison Mould

9. Equipment set-up

10. Dosing and mixing units

11. Dosing and mixing units

12. Blow Moulding Line – Extruder

13. Blow Moulding Line – Extruder • Functions of the extruder: • - Convey the granules in the screw flight • Compress the solid granule and remove the air • Melt the granules • Mix the melt, to make it as homogeneous as possible • Produce the desired melt temperature • Produce the desired pressure to have the melt flowing

14. Blow Moulding Line – Extruder • Typical extruder for blow moulding lines • Normally with grooved barrel • 3 zone screw or barrier screw with or without mixing elements

15. L Metering zone Feeding zone zone Compression zone Connection to the motor D q F P H D Screw diameter L Screw length q Flight angle (17.65) P Pitch F Feeding zone depth H Metering zone depth A Feeding zone length/D C Compression z. depth/D M Metering z. length/D N Screw speed, rpm Screw

16. Screw • Typical 3-zone screw: • D= 90 mm L/D= 25 Compression ratio: 2.0 to 2.5 • Length feed section: 10D • Length compression section: 6D • Length metering section: 9D • Typical barrier screw with mixing head: • L/D: 20

17. Screw 3 Multi-Purpose Barrier Screw for Grooved Barrels

18. Mixing elements 2 Shear & mixing elements

19. Screw 3 Multi-Purpose Barrier Screw for Grooved Barrels

20. DISTRIBUTIVE (ananas, Saxton, Dulmage) Theydivideandrecombineflowstreams DISPERSIVE (UCC; cavity transfer mix, static mixer) Cutting strains generate the reduction of particles of immiscible components

21. Mixing elements

22. Mixing elements 3

23. Grooved barrel Grooved zone Cooling

24. Filters – Screen pack – Filter Changer old filter new filter

25. Types of dies • Spiders (PVC) • Mandrel • Spyral

26. Mandrel die • Low cost • Reduced external dimensions • High precision with annular die gap • Difficult centering • Long time needed for color change • Output depending

27. Standard die

28. Multiple die

29. Die design and polymer swell

30. Die design and polymer swell

31. Coextrusion dies for 3 layers

32. Coextrusion die for 6 layers and wall structure

33. State-of-the-art structure of multilayer bottles 2 layers PE-LD/PE-HD 3 layers PET/PET/PET PET/PA/PET PE-HD/R PE-HD /PE-HD PE-HD/Adhesive/PA PE-HD/Adhesive/EVOH 4 layers PE-HD/R PE-HD/Adhesive/PA or EVOH

34. State-of-the-art structure of multilayer bottles 5 layers PE-HD/adhesive/EVOH/adhesive/PE-HD PE-HD r PP EVOH or PA 6 layers PE-HD/R PE-HD/adhesive/EVOH/adhesive/PE-HD PE-HD or PP EVOH or PA

35. Radial flow head – Heart shaped melt flow channels

36. Radial flow head – Heart shaped melt flow channels • Distance to exit on the back side of the mandrel • is shorter than the one of the extruder side = lower • pressure drop • - Reduces parison bending • Melt parted in two (180°) for optimized distribution • of thickness • - Fusion lines on the opposite part of entry

37. Die centering Die mandrel can be centered by means of adjustment bolds. Poor centering leads to uneven wall thickness distribution,resulting in poor bottle stiffness.

38. Die deformation • No flexibility • Used for containers with • special form (strong oval shape, • square)

39. Die deformation/Partial thickness control (PWDS)

40. Parison thickness control • Programming parison thickness • through electronic system to optimize • container wall thickness and • performance

41. Parison thickness control Vertical mandrel movements modify the die gap thus the parison thickness (and its swell)

42. Blowing systems • - Blowing is done aside of the die • Blowing pin descends in to the neck opening (continuous extrusion • lines, with or without neck calibration)

43. Blowing systems • Blowing pin is part of the mandrel (Uniloy equipments) intermittent, with neck calibration • Blowing pin replaced by a needle (carousel lines for aseptic containers or toys)

44. Blowing systems • Two blowing pins moving aside, used for flat articles with high widening • ratio. One of the pin is the blowing pin.

45. Blowing systems • Blowing air needs high pressure • Too high air pressure causes protrusions closed to the partition lines of • the mold • Too low pressure causes air trapping, rough surface and partition lines • not homogeneous • Pre-cooled air or liquid nitrogen can help reducing cycle time and • increasing production

46. Blowing systems • Pre-blowing with open parison • - avoids parison collapse • Pre-blowing with closed parison • - reduces parison elongation • - optimize mold filling • - improve formation of partition lines • (by reducing accumulation at the end • of the lines contributes to control • parison/container thickness • - reduce blowing time for large containers

47. Parison cut • Cold knives for HDPE (hot for PP) • Tear through head movements • (Uniloy lines and large containers) • Tear through mold movements

48. Moulds • Manufactured using aluminum alloys with high heat transfer • Inserts for de-flashing made of steel with low abrasion coefficient

49. Moulds 2 – Mould glossary

50. Moulds 3 • Mould movements • normally the mould moves aside of the die to avoid the descending • parison stitching on the mould