A single sample of rPET can look excellent on paper. What manufacturers need is harder to deliver: material that looks and behaves the same way delivery after delivery, so that production lines do not have to be adjusted every time a new batch arrives.
Why it matters on the production line
Preform and bottle makers tune their machines to the material they run. When the material changes, the settings stop fitting. Bottles can come out hazy or weak, wall thickness can vary, and more parts end up rejected. Inconsistent rPET costs not only quality but also time and output.
The properties that matter most
Intrinsic viscosity (IV)
IV reflects the length of the polymer chains. It affects how the material flows and stretches during moulding, and how strong the finished bottle is. A narrow, predictable IV range keeps processing settings stable.
Colour
Colour is measured as L, a and b values: lightness, the red to green axis and the yellow to blue axis. For clear packaging, customers expect a bright, neutral colour without a yellow tint.
Acetaldehyde (AA)
Acetaldehyde forms when PET is heated during processing. Even small amounts can affect the taste of sensitive products such as water, so it is kept low and checked regularly.
Where consistency comes from
Consistent rPET is not achieved at the end of the line. It is built in at every stage:
- Careful sorting, so the material entering the process is as uniform as possible.
- Close process control, monitoring each stage and correcting deviations before they reach the product.
- Regular testing, so every batch is checked against the same specification.
For manufacturers, the result is simple: predictable settings, less waste and the confidence to commit to recycled content. That is why consistency, more than any single test result, is the real measure of rPET quality.