Meaning
Amorphous thermoplastic polyester modified with cyclohexanedimethanol possesses high clarity, toughness and chemical resistance. In the thermoforming industry, polyethylene terephthalate glycol is widely used for medical packaging and displays because it does not crystallize during heating.
Thermoforming Window
Thermal processing of this polymer is simplified by the absence of a distinct melting point. Because polyethylene terephthalate glycol is amorphous, it has a wide thermoforming window, allowing for easy forming without the risk of whitening or hazing. This makes it an ideal choice for producing clear, rigid blister packs that require strict visual inspection.
The wide processing range also means that moulders can achieve deep draw ratios with less risk of localized thinning or webbing, which reduces scrap rates.
Moisture Sensitivity
Hygroscopic materials absorb moisture from the surrounding air, which can cause processing defects. Like most polyesters, polyethylene terephthalate glycol must be thoroughly dried before processing to prevent hydrolytic degradation. Processing undried resin leads to molecular weight loss, which reduces the impact strength of the moulded parts and causes cosmetic splay.
Regrind Economy
Reusing scrap material is essential for reducing production costs in packaging operations. Since polyethylene terephthalate glycol is thermally stable and amorphous, regrind can be blended with virgin resin without causing major changes in melt viscosity or optical clarity. This recycling capability lowers material costs while maintaining the structural integrity of the thermoformed containers.
