Very few readers of this issue can remember, or even imagine, what it was like when an injection molding machine did not have a screw, but only a smooth-bore plunger.

Very few readers of this issue can remember, or even imagine, what it was like when an injection molding machine did not have a screw, but only a smooth-bore plunger. Very few can remember a time when there were no twin-screw extruders; no multi-layer film, sheet, or bottles; no accumulator-head or injection blow molders; no polypropylene, HDPE, or polycarbonate; and no such thing as RIM or rotomolding or structural foam—or even a melt indexer. How and when these technologies got started are just some of the little-known stories that are told in the following pages. Fifty stories, in fact—one for each year this magazine has been reporting on the latest ways to manufacture with plastics.

So many essential technologies surfaced in the last half-century that it was perplexingly difficult to select just 50 to celebrate here. We invited long-time industry experts in all areas of plastics to help us make those choices. Turn the page to see who they are.

Even with the help of nearly 2000 years of collective plastics experience, our editors had to make some tough calls. For example, we ruled out microprocessor controls because the computer revolution has had a universal impact, and plastics rode the wave along with every other industry. Likewise, we left out printing and decorating technologies because they had prior history with other materials. We also had to skip worthy candidates in some fields so as to broaden our coverage to all areas of plastics. Please note that we have not presented these 50 innovations in any particular order, except for the first four, which did pull the most votes.

Some readers may disagree with our choices, and some may argue over who deserves pioneering credit in a particular field. Our editors found it much harder than expected to retrace the history of these 50 innovations. So few eyewitnesses to this history are still accessible for interviews. Relatively little has been published on this field of technological history. And many records were lost or discarded in the myriad corporate mergers over the decades. So we often had to rely on individuals’ memories of past decades. And we had to resolve inevitable disagreements over some dates and facts.

You’ll see that it was worth it. These are important stories. They reveal the origins of so much that we take for granted—in brilliant intuition, hard work, or plain good luck.

 

Top 50 Innovations

  1. Reciprocating Screw Injection
  2. Polypropylene
  3. HDPE
  4. Polycarbonate
  5. Twin-Screw Extrusion
  6. LLDPE
  7. Sheet Molding Compound
  8. Ultrasonic Welding
  9. Stretch-Blow Molding
  10. Desiccant Dryers
  11. ABS Resins
  12. Parison Programming
  13. Structural Foam
  14. Barrier Screws
  15. Accumulator-Head Blow Molding
  16. Super-High-Heat Thermoplastics
  17. Melt Indexers
  18. Carbon Fiber
  19. Injection Molding Simulation
  20. Thermoplastic Elastomers
  21. Hot Runners
  22. Takeout Robots
  23. Pressure Forming
  24. Rotary Thermoforming
  25. Halogenated Flame Retardants
  26. PET and PBT
  27. Film/Sheet Coextrusion
  28. Multi-Material Injection
  29. Multi-Layer Blow Molding
  30. Hindered Phenolic Antioxidants
  31. HALS UV Stabilizers
  32. All-Electric Injection Presses
  33. Rotational Molding
  34. Gas-Assist Molding
  35. In-Mold Decorating & Labeling
  36. Cavity-Pressure Sensing
  37. Spray-Up Composites
  38. Injection Blow Molding
  39. Pur Thermal Insulation
  40. RIM
  41. Foam Extrusion
  42. Underwater Pelletizing
  43. Chemical Blowing Agents
  44. Spiral Dies for Pipe & Blown Film
  45. Auto Gauge Control for Blown Film
  46. Auto Gauge Control for Flat Dies
  47. Biaxial Film Orientation
  48. Film/Sheet Thickness Sensors
  49. Density Separation of Mixed Waste
  50. Computerized Color Matching