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PET bottles scrap

Hello, I'm a student at the Material Engineering Department and I'm writing a technical report on the following issue: " PET bottles Scrap and its potential reuse". I am trying to find answers for some of my questions regarding the use of PET bottles scrap in industry and the problems that occur while working with this material. I'd be glad if you could help me with some of the questions:

  1. What is the definite PET-structure in the bottle (crystalline or/and amorphous);
  2. Could we reuse PET bottles Scrap as 100% for new bottles production?
  3. If "not", why? What are the problems and difficulties in such use?
  4. Why PET bottles Scrap dosage does not exceed the 30% for new bottles production?
  5. What is the other PET bottles Scrap potential processing applications?
  6. What are potential dosages for PET bottles Scrap using in these applications?
  7. Why PET bottles Scrap is not used for "injection molding" processes, like in "extrusions" ones?
  8. May be the best solution for PET bottles Scrap is depolymerization process ?

I'll be very appreciative for detailed answers, Thanks in advance, Gregori Shuster

Reply to
Gregori Shuster
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The bulk of the bottle is crystalline - oriented - but the neck is not.

Not a good idea since PET could be contaminated.

Besides contamination, polymer will probably lose molecular weight.

If so, I would suspect color problem. There are dyes added to take away yellow cast but too much dye causes light transmission loss.

Textile fibers, minivan bumpers, any non-food use you can think of. Off color is potential problem.

100% nobody cares for example, what the color of their tire cord is.

It is. You don't want to brag that you use recycled polymer in your premium product.

This process has been going on for years. All kinds of crap ends up in the depolymerizers and main problem is off color so products not used in critical color uses.

Reply to
Frank Logullo

Hallo, I hope I haven't missed the time slot for this thread. Another problem with reusing PET scrap (and even with the initial processing) is degradation of the PET, in the presence of moisture, to produce acetaldehyde. This is fine if the bottles are going to contain cider or appleade, but gives defenite off-flavours in other drinks, even beer. Regards, Bill

Reply to
Bill

Any extrusion of PET resin, scrap or virgin, requires exclusion of all water. Acetaldehyde is generated by hydrolysis and pyrolysis of resultant hydroxyethyl end groups. Polymer degradation and loss of physical properties is worse result of hydrolysis. It is probably not a good idea to re-extrude scrap into food containers because of potential for contamination. Frank

Reply to
Frank Logullo

All these points are accurate BUT, pet bottles are being recycled back to food use bottles at 100% without any depolymerising in Canada and in Europe, I don't know about the USA, but approval has been gained there. However the biggest application is still fibre. Many sites on the net discuss this.

Reply to
colin

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