What is PET Material?
PET stands for Polyethylene Terephthalate (also known as Polyester). It is the most widely used thermoplastic polyester and belongs to the family of engineering plastics.
Most people know PET through its two common forms: Polyester fiber (clothing fabric) and PET bottles (drink containers).
1. Key Properties of PET
| Property | Description |
|---|---|
| High transparency | Good gloss and light transmission, similar to glass |
| Good mechanical strength | Rigid, impact-resistant, good flex resistance (especially when biaxially oriented) |
| Chemical resistance | Resists dilute acids, oils, and most solvents; not resistant to strong alkalis or hot water |
| Moderate heat resistance | Heat deflection temperature ~70-80°C (158-176°F); long-term use below 60-70°C (140-158°F) |
| Good barrier properties | Effective barrier against oxygen, carbon dioxide, and moisture vapor |
| Recyclable | High recycling value; resin identification code 01 |
| Low moisture absorption | Must be thoroughly dried before injection molding (otherwise hydrolyzes) |
2. Main Applications
(1) Packaging Industry (Largest Use)
Water bottles, carbonated soft drink bottles, cooking oil bottles, condiment bottles
Sheet/trays: fruit containers, fresh meat trays, electronic component trays
(2) Textile Industry
Polyester fiber: clothing fabrics, home textiles, outdoor gear
Non-woven fabrics: filter media, wet wipes, etc.
(3) Electronics & Industrial
PET film: motor insulation, flexible circuit board substrates, solar backsheets, audio/video tape substrates
Reinforced PET: Glass fiber reinforced grades used for automotive parts, relay housings, connectors (significantly improved mechanical strength)
(4) Other Applications
3D printing filament (PETG)
Medical packaging (compatible with steam or ethylene oxide sterilization)
3. Common Forms of PET Compared
| Form | Characteristics | Typical Applications |
|---|---|---|
| General PET | Transparent, stiff, relatively brittle | Beverage bottles, sheets |
| Oriented PET | Biaxially oriented – greatly increased strength, higher clarity | Film, tape substrates |
| Reinforced PET | Glass/mineral filled – improved heat resistance and rigidity | Engineering structural parts, automotive components |
| PETG | Copolyester – transparent, less brittle, easier to process | Cosmetic bottles, display stands, medical devices |
4. Limitations of PET
Poor heat resistance – Cannot be used in high-temperature environments (e.g., microwave ovens)
Not resistant to strong alkalis – Hydrolyzes and degrades in strong alkaline conditions
High processing requirements – Must be thoroughly dried before molding; otherwise bubbles and surface defects (silver streaks) will occur