Identification of Recycled Polyester

Identification of Recycled Polyester

Test to recognise recycled polyester to check the presence of other textile materials inside.


An increasingly important request for the assessment of textile sustainability is linked to tests to identify recycled polyester, aimed at ascertaining the presence and amount of rPET inside materials.

These analytical tests are based on the identification of isophthalic acid (IPA), used in the polyester production process for making plastic bottles (bottle to fibre process). Over 95% of the polyester recycled for the production of recycled fabric comes from the mechanical recycling of polyester from bottles and therefore, quantification of IPA content is an index of the percentage of recycled material.

Another technique for this process is the qualification of recycled polyester based on analysis of the differential scanning calorimetry (DSC): the differences in the profiles (thermograms) that can be observed in recycled polyester (whether mechanically recycled [from bottles] or chemically recycled [from textiles]), may be used to identify polyester materials prevalently from chemical recycling in the near future.