## Recycled TPU Elastomer Footwear Grade: Sole Manufacturing Process and Durability
### Introduction
Thermoplastic polyurethane (TPU) recycled from industrial scrap and post-consumer products offers excellent properties for footwear sole applications. This article covers manufacturing processes and durability performance.
### Material Properties
**Mechanical**:
– Hardness: 80-95 Shore A
– Tensile strength: ≥25 MPa
– Tear strength: ≥50 kN/m
– Abrasion resistance: <100 mm³ (DIN 53516)
**Processing**:
- Injection temperature: 180-210°C
- Mold temperature: 40-60°C
- Cycle time: 30-60 seconds
### Recycling Sources
**Industrial Scrap**:
- Extrusion edge trim
- Injection molding sprues and runners
- Off-specification batches
**Post-Consumer**:
- Used footwear soles
- Industrial belts and hoses
- Automotive interior components
### Manufacturing Process
**Reprocessing**:
1. Size reduction (5-10mm flakes)
2. Washing and drying
3. Melt extrusion with additive package
4. Pelletizing
5. Quality testing
**Sole Production**:
1. TPU pellet drying (80°C, 2-4 hours)
2. Injection molding into sole molds
3. Cooling and demolding
4. Surface treatment (if required)
5. Assembly with upper
### Durability Testing
**Abrasion**: DIN 53516 rotating drum test
**Flex Resistance**: Ross flexing (300,000 cycles)
**Compression Set**: 22 hours at 70°C
**Hydrolysis Resistance**: 85°C/85% RH aging
### Brands Using Recycled TPU
- Adidas (Parley collection)
- Nike (Space Hippie)
- Allbirds (Dasher series)
- Veja (Campo Chrome Free)
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**Keywords**: recycled TPU elastomer, footwear sole, TPU manufacturing, recycled rubber sole,durability testing