Ever notice those little triangles with numbers on plastic packaging? They’re more than just symbols—they tell you what kind of plastic you’re dealing with. As a custom food packaging supplier, we think it’s super important to understand these Plastic Resin Identification Codes. Whether you’re packaging salad, snacks, or smoothies, knowing the difference between PET, HDPE, and the rest helps you make smarter choices for safety, sustainability, and recycling.
1. Overview of Plastic Resin Identification Codes
| Code | Abbreviation | Material | Common Uses |
| 1 | PET or PETE | Polyethylene Terephthalate | Bottles, jars |
| 2 | HDPE | High-Density Polyethylene | Milk jugs, detergent bottles |
| 3 | PVC | Polyvinyl Chloride | Cling film, pipes (less food-safe) |
| 4 | LDPE | Low-Density Polyethylene | Bread bags, frozen food bags |
| 5 | PP | Polypropylene | Yogurt containers, caps |
| 6 | PS | Polystyrene | Foam trays, disposable cutlery |
| 7 | OTHER | Other plastics (e.g., PLA, BPA) | Multilayer materials |
2. 1 – PET or PETE (Polyethylene Terephthalate)
Description: A clear, lightweight, strong plastic with good gas and moisture barrier properties.
Common Uses:
- Water and soft drink bottles
- Salad dressing and oil bottles
- Peanut butter jars
- Food trays (oven-ready)
Properties:
- Transparent and shatter-resistant
- Impermeable to CO₂, hence good for fizzy drinks
- Lightweight and inexpensive
Safety:
- Generally considered safe for single use.
- Not ideal for reuse due to potential bacterial growth and degradation.
Recyclability:
- Widely accepted in curbside recycling
- Recycled into: polyester fibers (clothing, carpets), containers, strapping
3. 2 – HDPE (High-Density Polyethylene)
Description: A stiff, strong plastic with high resistance to chemicals and moisture.
Common Uses:
- Milk and juice jugs
- Detergent and shampoo bottles
- Cereal box liners
- Ice cream tubs
Properties:
- Opaque and robust
- Strong resistance to impact and chemicals
- Withstands lower temperatures
Safety:
- Very safe for repeated food contact
- No known leaching problems
Recyclability:
- Widely recyclable
- Recycled into: piping, plastic lumber, picnic tables, new bottles
4. 3 – PVC (Polyvinyl Chloride)
Description: A versatile plastic, used both rigid and flexible, but has health and environmental concerns.
Common Uses:
- Cling film and food wrap (less common now)
- Cooking oil bottles
- Blister packaging (e.g., pills)
- Pipes and window frames
Properties:
- Strong and durable
- Excellent chemical and oil barrier
- Often plasticized for flexibility (can leach chemicals)
Safety:
- Health concerns due to chlorine content and additives like phthalates
- Can release dioxins when incinerated
Recyclability:
- Difficult to recycle
- Few facilities accept it
- Not recommended for food contact anymore in many regions
5. 4 – LDPE (Low-Density Polyethylene)
Description: A flexible, tough plastic commonly used in thin-film applications.
Common Uses:
- Bread bags
- Frozen food packaging
- Squeeze bottles (e.g., honey, mustard)
- Stretch wrap
Properties:
- Flexible and soft
- Good moisture barrier
- Low melting point
Safety:
- Considered safe for food
- Often used in direct food contact items
Recyclability:
- Limited recyclability
- Not always accepted in curbside bins
- Recycled into: garbage can liners, floor tiles, shipping envelopes
6. 5 – PP (Polypropylene)
Description: A durable plastic resistant to high temperatures.
Common Uses:
- Yogurt and margarine tubs
- Microwaveable containers
- Take-out food containers
- Straws, bottle caps
Properties:
- Strong and fatigue-resistant
- Withstands high heat (microwave- and dishwasher-safe)
- Excellent chemical resistance
Safety:
- Very safe for hot food and liquids
- Stable and unlikely to leach
Recyclability:
- Growing recyclability
- Often recycled into: signal lights, battery cables, brooms
7. 6 – PS (Polystyrene)
Description: A rigid or foam plastic that’s light and insulating, but controversial.
Common Uses:
- Foam cups and plates
- Takeaway food containers
- Egg cartons
- Meat trays
Properties:
- Lightweight and insulating
- Can be rigid or foamed (Styrofoam)
- Brittle and easily breaks
Safety:
- Can leach styrene, a possible carcinogen, especially when heated
- Not recommended for hot food
Recyclability:
- Rarely recycled
- Difficult and uneconomical
- Often ends up in landfills or oceans
8. 7 – Other (Mixed/Unknown Plastics)
Description: A catch-all for plastics not in groups 1–6, including both synthetic and bio-based materials.
Common Uses:
- Large water jugs (5-gallon)
- Baby bottles (older models)
- Food containers with multi-layer materials
- PLA (polylactic acid – biodegradable plastic)
Properties:
- Varies widely
- Can be clear, colored, flexible, or rigid
- Includes newer bioplastics and composites
Safety:
- Some contain BPA (bisphenol-A), a chemical with potential health risks
- Bio-based plastics like PLA are safer but only industrially compostable
Recyclability:
- Rarely recycled
- Typically not accepted in curbside programs
- Bio-based plastics often require special composting facilities
Conclusion
At the end of the day, those numbers on your packaging matter. They help you choose the right plastic for the job—and make it easier to recycle or reuse. At TrustPrints, we’re here to help you pick materials that not only work great but also do better for the environment. A little knowledge goes a long way when it comes to packaging!