- Common Types of Plastic Packaging Materials
- PET (Polyethylene Terephthalate)
Identification: Recycling symbol number 1 ♳
Characteristics: Transparent, lightweight, resistant to grease, resistant to weak acids and alkalis, but poor heat resistance (≤70℃).
Usage: Beverage bottles (such as mineral water bottles), edible oil bottles, food trays.
Environmental friendliness: Recyclable, but repeated use may release harmful substances, avoid repeatedly filling with hot water.
- HDPE (High-Density Polyethylene)
Identification: Recycling symbol number 2 ♴
Characteristics: Corrosion-resistant, impact-resistant, opaque, good heat resistance (≤110℃).
Usage: Cleaning agent bottles, milk bottles, cosmetic containers, shopping bags.
Environmental friendliness: Recyclable and renewable, often used for making daily necessities.
- PVC (Polyvinyl Chloride)
Identification: Recycling symbol number 3 ♵
Characteristics: Flexible, strong barrier, but contains chlorine which may release toxic gases (heating).
Usage: Transparent packaging films, medicine blister packs, card packaging.
Environmental friendliness: Difficult to recycle, burning easily produces dioxins, gradually being replaced.
- LDPE (Low-Density Polyethylene)
Identification: Recycling symbol number 4 ♶
Characteristics: Soft, resistant to low temperatures, high air permeability.
Usage: plastic bags， flexible packaging.
Environmental friendliness： Recyclable， but low recycling rate， prone to causing white pollution.
- PP (Polypropylene)
Identification： Recycling symbol number 5 ♷
Characteristics： High temperature resistance (≤130℃)， resistant to chemical corrosion， high hardness.
Usage： Microwave oven trays， straws， yogurt cups， medicine bottles.
Environmental friendliness： Recyclable， stable but difficult to degrade.
- PS (Polystyrene)
Identification： Recycling symbol number 6 ♸
Characteristics： Hard and brittle or foamed (such as foam plastic)， good heat insulation， not resistant to high temperatures.
Usage： Fast food boxes， cup lids， disposable tableware.
Environmental friendliness： Difficult to recycle， burning causes significant pollution， many countries restrict its use.
- Other types (such as PLA， PVA， etc.)
PLA (Poly Lactic Acid)： Biobased degradable plastic， derived from corn starch， suitable for making food packaging， but requires industrial composting conditions for degradation.
PVA (Polyvinyl Alcohol)： Water-soluble film， used in laundry beads， etc.， environmentally friendly but costly.
- Key Points for Selecting Plastic Packaging
Functional requirements
High temperature resistance: Choose PP, HDPE.
Transparency: Choose PET, PVC.
Low cost: LDPE, PP.
High performance: PET, PC (non-food category).
III. Environmental Replacement Trend
Recyclable design: Single-material packaging enhances recycling efficiency.
Biobased plastics: Such as PLA, PBAT (requires improved degradation facilities).
Reduction: Lightweight packaging reduces plastic usage.
- Identification Methods for Plastic Packaging Materials
Check the bottom triangular mark: Numbers 1-7 correspond to materials.
Physical tests:
Combustion method: PET burns with black smoke, PP has a waxy smell, PVC is pungent.
Density method: HDPE floats on water, PVC sinks to the bottom.