Detailed Description
TPU vs PUR — The Chemistry Behind the Performance
TPU (thermoplastic polyurethane) and PUR (cross-linked polyurethane / TMPU) are chemically related — both are polyurethane polymers. The critical difference is in the polymer structure:
- TPU is thermoplastic: The polymer chains are linear with reversible hydrogen bonds between them. TPU can be melted, extruded, and remelted — like any thermoplastic. This thermal processability allows tighter control over extrusion parameters, producing a more uniform jacket with fewer surface defects
- PUR is thermoset: The polymer chains are chemically cross-linked (cured). Once formed, PUR cannot be remelted. Cross-linking provides excellent chemical and heat resistance but limits process control during extrusion
1. Superior Surface Quality
TPU's controlled melt rheology during extrusion produces an exceptionally smooth, defect-free jacket surface with a friction coefficient ≤0.20. This matters on reeling drums where jacket-to-jacket contact during spooling can cause sticking, uneven layering, and abrasion. A smoother surface = more consistent spooling = fewer reeling defects.
2. Better Abrasion Resistance
TPU achieves Taber ≤3 mg at Shore 85–92 A. Standard PUR achieves Taber ≤5 mg at Shore 85–90 A. The 40% improvement comes from TPU's ability to form a more ordered hard-segment crystalline structure during controlled extrusion cooling — creating microscopic abrasion-resistant domains in the jacket surface.
3. Superior Low-Temperature Impact Resistance
At -50°C, TPU retains elastic behavior — it can be struck, bent, and compressed without cracking. Standard PUR becomes brittle at approximately -40°C to -45°C. For reeling applications in Arctic, high-altitude, or cold-storage environments, this is the critical differentiator.
When TPU Justifies Its Premium
| Application Requirement | PUR Sufficient? | TPU Justified? |
|---|---|---|
| Standard reeling (< 300 000 cycles) | ✅ | ❌ Over-specified |
| High-cycle reeling (> 300 000 cycles) | ⚠️ Borderline — approaching PUR life limit | ✅ 500 000+ cycle life |
| Cold-climate operation (< -40°C) | ❌ PUR brittle limit | ✅ Flexible at -50°C |
| Abrasive environment (mining, steel) | ⚠️ PUR wears faster | ✅ 40% better abrasion |
| Impact-prone reel flanges | ⚠️ PUR can tear | ✅ Superior impact resistance |
| Cost-sensitive application | ✅ Better value | ❌ TPU is 15–25% premium |
| Marine/salt spray | ✅ PUR adequate | ⚠️ TPU comparable — not better |
TPU Abrasion — Why It Matters on Reels
Reeling abrasion is different from drag chain abrasion. In a drag chain, the cable slides against the carrier floor — one contact surface, smooth plastic or metal. In a reel, the cable slides against itself — adjacent turns in contact, multiple layers deep.
TPU's advantage for reeling:
- Self-to-self abrasion: TPU-on-TPU contact has lower friction than PUR-on-PUR. Each turn slides past adjacent turns with less resistance during spooling and unspooling
- Layer compression abrasion: On deep-drum reels, the inner layers are under sustained compressive load from the layers above them. TPU's higher hardness (92 A achievable) resists the slow abrasive deformation that occurs when compressed surfaces micro-move against each other
- Edge abrasion: Cable contact with drum flanges during spooling can cut into the jacket. TPU's superior tear strength (≥80 N/mm) resists flange-edge cutting better than PUR (≥60 N/mm)
Environmental Advantage — TPU Is Recyclable
Cross-linked PUR cannot be remelted — at end of life, the only disposal options are landfill or incineration. TPU, being thermoplastic, can be reground and reprocessed into new TPU products. While the copper conductor is the primary recycling value in any cable, choosing TPU eliminates the cross-linked PUR jacket as a non-recyclable waste stream.
This matters for:
- EU machinery exports under the Circular Economy Action Plan
- Corporate sustainability programs with end-of-life product responsibility
- Tender specifications requiring recyclable cable materials
Why Choose Yichi Cable TPU Reeling?
- Optimized TPU grade for reeling: Our TPU compound is specifically formulated for reeling applications — not a general-purpose TPU used for injection-molded parts. The abrasion resistance and surface finish are optimized for drum winding
- Hydrolysis-stabilized polyester TPU: Standard polyester TPU degrades in wet environments through hydrolysis. Our TPU contains a hydrolysis stabilizer package that extends wet-environment service life
- Verified reeling life: >500 000 cycle rating is based on actual drum reeling tests at 15:1 D/d in our CNAS-accredited lab — not extrapolated from material data sheets
- Cold-impact certification: Impact resistance at -50°C is verified per ASTM D256 / ISO 180 Izod impact test — critical for Arctic and cold-climate applications
- Recyclability documentation: We provide material composition documentation enabling end-of-life TPU jacket recycling — supporting your environmental compliance requirements