Glycol-modified PET and copolyesters (PETG) offer a desirable combination of properties such as clarity, toughness, and stiffness.
Typical Applications
- medical devices
- toys
- displays and lighting fixtures
- face shields
- refrigerator crisper pans
Injection molding processing conditions
- Drying
- Drying is essential for PETG prior to injection molding. The moisture level must be below 0.04%. Drying temperature is not to exceed 66°C [150°F]. Drying at approximately 65°C [149°F] for 4 hours is recommended.
- Melt Temperature
- 220°C–290°C [428°F–554°F]; the melt temperature is grade specific
- Mold Temperature
- 10°C–30°C [50°F–86°F], recommended 15°C [60°F]
- Material Injection Pressure
- 30 MPa-130 MPa
- Injection Speed
- High speeds without causing embrittlement
Chemical and Physical Properties
PETGs (or copolyesters) are glycol-modified PETs. The modification is achieved by adding a second glycol during polymerization. The resulting molecular structure is irregular and the material is clear and amorphous with a glass transition temperature of 88°C [190°F]. PETGs can be processed over a wider processing range than conventional PETs and offer a good combination of properties such as toughness, clarity, and stiffness.