EN
DE
PE
Material Type
General Plastics
Material Full Name
Polyethylene
Process Compatibility
Injection Molding, CNC Machining
Basic Properties
Property |
Parameter/Performance |
Remarks |
|---|---|---|
| Chemical Name | Polyethylene | Polymerized from ethylene monomer |
| Molecular Structure | Semi-crystalline thermoplastic | Classified as LDPE (branched), LLDPE (linear), HDPE (high crystallinity) |
| Density | 0.91~0.97 g/cm³ | LDPE: 0.91-0.93 / LLDPE: 0.92-0.94 / HDPE: 0.94-0.97 |
| Transparency | Semi-transparent (LDPE) to opaque (HDPE) | Light transmission: LDPE (75%), HDPE (<30%) |
| Mechanical Properties | ||
| – Tensile Strength | LDPE: 10-20 MPa / HDPE: 20-35 MPa | HDPE strength is 2× higher than LDPE |
| – Elongation at Break | LDPE: 300-600% / HDPE: 500-1000% | Ultra-high toughness |
| Thermal Properties | ||
| – HDT (0.45MPa) | LDPE: 40-50℃ / HDPE: 60-80℃ | Heat-resistant grades (e.g., PE-RT) withstand 90℃ |
| – Service Temperature | -50℃~80℃ (short-term 100℃) | Excellent low-temperature performance (flexible at -70℃) |
| Chemical Properties | ||
| – Chemical Resistance | Resists acids/alkalis/alcohols; weak against aromatics/halocarbons | HDPE outperforms LDPE |
| – Permeability | High gas/water vapor transmission (LDPE highest) | Requires barrier layers for food packaging |
Processing Characteristics
Thermal Stability:
- Processing temps: LDPE (160-240℃)/HDPE (180-280℃)
- Degrades above 300℃ (avoid oxidative degradation)
Flowability:
- Melt Index: 0.1-50 g/10min (190℃/2.16kg)
- Ultra-high MI (>20) for thin-wall molding.
Processing Methods:
- Blow molding (50%): Bottles/fuel tanks
- Extrusion (30%): Pipes/films
- Injection molding (20%): Consumer/industrial parts
Common Application Areas
-
Packaging: Shopping bags (LDPE), liquid packaging (HDPE)
-
Construction: Gas pipes (HDPE), underfloor heating pipes (PE-RT)
-
Medical: Disposable syringes (HDPE), artificial ligaments (UHMWPE)
ABS Modified Types
Type |
Characteristics |
Typical Applications |
|---|---|---|
| LDPE (Low Density) | High flexibility, easy processing, good clarity | Plastic bags, agricultural film |
| LLDPE (Linear Low Density) | Superior puncture/tear resistance | Stretch wrap, flexible packaging |
| HDPE (High Density) | High rigidity, low permeability | Milk bottles, pipes, storage crates |
| UHMWPE (Ultra-High MW) | Extreme wear resistance (8× nylon) | Artificial joints, ballistic armor |
| mPE (Metallocene) | Narrow MW distribution, balanced strength/clarity | Premium food packaging films |
Advantages & Disadvantages
Advantages |
Disadvantages |
|---|---|
| Best chemical resistance | Requires surface treatment for printing/adhesion (corona/flame) |
| Exceptional low-temperature toughness | Limited heat resistance (HDPE <80℃ long-term) |
| Lowest-cost commodity plastic | Prone to stress cracking (with detergents/oils) |
Other General Plastics Selection
PP Materials
ABS Materials
PMMA Materials
PVC Materials
PS Materials
FAQ Of PE Materials
Visit our FAQ center for more questions.
What's the difference between LDPE and HDPE? Which should I choose?
|
Property |
LDPE |
HDPE |
|---|---|---|
| Density | 0.91-0.93 g/cm³ | 0.94-0.97 g/cm³ |
| Transparency | Semi-transparent (75%) | Opaque (<30%) |
| Tensile Strength | 10-20 MPa | 20-35 MPa |
| Max. Temp. | 50℃ | 80℃ |
| Best For | Flexible films, bags | Rigid containers, pipes |
Selection Guide:
- Need flexibility → Choose LDPE
- Need rigidity → Choose HDPE
Why does PE have poor adhesion for printing/painting? How to improve?
Root Cause:
- Non-polar surface (surface energy <31 dynes/cm)
Solutions:
Surface Treatments:
- Corona treatment (39-42 dynes/cm)
- Flame treatment (40-44 dynes/cm)
Additives:
- Primer coatings
- Incorporate polar monomers (e.g., PE-g-MAH)