EN
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PU
Material Type
Rubber
Material Full Name
Polyurethane Rubber
Process Compatibility
Injection Molding, Compression Molding
Basic Properties
Property |
Parameter/Performance |
Remarks |
|---|---|---|
| Chemical Name | Polyurethane Rubber | Contains urethane groups (-NH-CO-O-), divided into polyester (AU) and polyether (EU) types |
| Molecular Structure | Block copolymer (hard/soft segments) | Hard segments (diisocyanate) provide strength, soft segments (polyether/polyester glycol) enable elasticity |
| Density | 1.10~1.25 g/cm³ | 20-30% heavier than NR but superior volumetric performance |
| Color | Transparent to light yellow (colorable) | Medical grades require ISO 10993 compliance |
| Mechanical Properties | ||
| – Tensile Strength | 20-50 MPa (up to 80 MPa for TPU) | Highest among rubbers, nearing engineering plastics (e.g., nylon 66) |
| – Elongation at Break | 300-800% | Polyether (EU) > polyester (AU) |
| – Tear Strength | 50-100 kN/m | 3-5× higher than NR, extreme abrasion resistance (Akron wear <0.01 cm³/1.61km) |
| Thermal Properties | ||
| – Service Temperature | -30℃~80℃ (short-term 120℃) | Polyether better at low temps (-50℃), but prone to hydrolysis at high temps |
| – Thermal Conductivity | 0.2-0.3 W/(m·K) | Requires BN additives for heat dissipation (e.g., mining screens) |
| Chemical Properties | ||
| – Oil/Solvent Resistance | Resists mineral oils/fuels (polyester better) | Ester bonds vulnerable to hydrolysis (polyether resists 10× better) |
| – Weatherability | Needs UV stabilizers (e.g., carbon black/TiO₂) | 3-5 years outdoor service (shorter than NR) |
Processing Characteristics
Molding Processes:
- Casting (CPU): Prepolymer + chain extender (MOCA), cured at 80℃×24h
- Thermoplastic (TPU): Direct injection (barrel temp 180-220℃)
Key Parameters:
- NCO/OH ratio: 1.05-1.10 (controls crosslink density)
- Hardness range: Shore A 60-95 (broadest among rubbers)
Common Application Areas
-
Industrial: Conveyor belt scrapers (8× longer life than NR), slurry pump liners
-
Automotive: Suspension bumpers (dynamic modulus stability surpasses NR)
-
Medical: Artificial heart valves (polyether + anticoagulant coating)
PU Modified Types
Type |
Raw Materials |
Characteristics |
Typical Applications |
|---|---|---|---|
| Polyester (AU) | MDI + polyadipate glycol | High strength/wear resistance but hydrolytically unstable | Industrial rollers, mining screens |
| Polyether (EU) | TDI + PTMEG | Hydrolysis/low-temp resistant, dynamic performance | High-speed rail dampers, hydraulic seals |
| Thermoplastic (TPU) | – | Melt-processable (injection/extrusion) | Phone cases, sneaker soles |
| Microcellular PU | With blowing agents (e.g., water) | Density 0.2-0.6 g/cm³, high rebound | Car seats, shoe insoles |
Advantages & Disadvantages
Advantages |
Disadvantages |
|---|---|
| Highest mechanical strength in rubbers | Prone to hydrolysis at high temps (especially polyester) |
| Unmatched abrasion resistance (10× NR) | Poor weatherability (needs additives) |
| Widest hardness adjustability | High density (25% heavier than NR) |
Other Elastomer & Rubber Material Selection
NR Rubber
CR Rubber
IIR Rubber
FKM Rubber
TPU Rubber
FAQ Of PU Materials
Visit our FAQ center for more questions.
What distinguishes PU from conventional rubbers?
PU combines rubber elasticity with plastic strength:
• 10x more wear-resistant than NR (Akron abrasion <0.03cm³/1.61km)
• Ultra-wide hardness range (A20-D80, customizable)
• Load-bearing up to 50MPa (5x NBR) but poorer hydrothermal aging
Why must mining screens use Cast PU (CPU)?
CPU’s advantages in harsh conditions:
- Dynamic tear resistance >80kN/m (ISO 34-1 Method B)
- Withstands ore impact (remains flexible at -30℃)
- 3x service life vs metal screens (>18 months)
How to choose between TPU and thermoset PU?
Selection by production needs:
• TPU: Ideal for injection molding (cycle time <60s), recyclable
• Thermoset PU: Suits large parts (e.g., roller coatings), 10-20℃ higher heat resistance
• Key comparison: TPU has better elongation at break (>500%), thermoset PU offers lower compression set (<15%)