Thermoplastic polyurethane, often shortened to TPU material, is a flexible plastic that feels like rubber but processes like standard thermoplastics. It combines stretch, toughness, and chemical resistance, so factories mold, extrude, blow-form, or 3D-print it into shoe soles, phone cases, hoses, seals, and medical tubing. This guide explains TPU in clear language and uses tables and simple text charts for quick reference.
Innehållsförteckning
- TPU Definition and Basic Chemistry
- Benefits of Choosing TPU
- Key Properties of TPU
- Main TPU Grades and Types
- TPU Compared with Other Flexible Materials
- Processing Methods and Tips
- Design Guidelines for TPU Parts
- Typical Industrial Applications
- Återvinning och hållbarhet
- Vanliga frågor och svar
- Slutsats
TPU Definition and Basic Chemistry
TPU is a block copolymer that links hard segments (diisocyanates) with soft segments (polyols). The hard parts add strength and heat resistance, while the soft parts add stretch and low-temperature flexibility. Because the bonds are thermoplastic, you can melt and reshape TPU many times without heavy loss of performance.
Benefits of Choosing TPU
- Flexes like rubber yet processes on standard plastic machines.
- Absorbs shock and vibration without cracking.
- Resists many oils, fuels, and cleaning chemicals.
- Stays flexible down to about −40 °C for most grades.
- Offers transparent or colored options for consumer and medical parts.
Key Properties of TPU
| Fastighet | Typical Range | Why It Matters |
|---|---|---|
| Hårdhet (Shore A) | 60 – 98 | Lets you pick soft gel or firm shell |
| Draghållfasthet | 25 – 55 MPa | Withstands pull forces in straps and belts |
| Töjning vid brott | 300 – 700 % | Stretches far without tearing |
| Täthet | 1.10 – 1.25 g/cm3 | Lighter than many rubbers |
| Service Temperature | −40 °C to +90 °C | Covers winter sport gear to warm engine bays |
| Abrasion Loss | 25 – 40 mm3 (DIN) | Survives repeated wear in wheels or soles |
| Compression Set | < 40 % at 70 °C, 24 h | Keeps shape in seals and gaskets |
Hardness vs Flexibility (Text Chart)
Softer (Shore A 60) ████▌ Medium (Shore A 80) ██████████ Firm (Shore A 95) █████████████████████
Longer bars show higher hardness. Flexibility drops as hardness rises.
Main TPU Grades and Types
| Betyg | Base Chemistry | Main Benefit | Typical Use |
|---|---|---|---|
| Polyester TPU | Polyester soft segments | Oil and fuel resistance | Hydraulic hoses |
| Polyether TPU | Polyether soft segments | Better hydrolysis stability | Water-sport gear |
| Aliphatic TPU | Aliphatic diisocyanate | Non-yellowing clarity | Transparent phone cases |
| Conductive TPU | Filled with carbon or metal | Static dissipation | ESD mats and films |
| Biobased TPU | Renewable polyols | Lower carbon footprint | Sustainable fabrics |
TPU Compared with Other Flexible Materials
| Funktion | TPU | Silicone | TPE-S | Naturgummi |
|---|---|---|---|---|
| Service Temperature | −40–90 °C | −50–200 °C | −30–80 °C | −40–80 °C |
| Nötningsbeständighet | Utmärkt | Dålig | Rättvist | Bra |
| Oil Resistance | Bra | Dålig | Rättvist | Dålig |
| Kostnad | Medium | Hög | Låg | Låg |
| Processing Ease | Simple melt | Curing needed | Simple melt | Vulcanization |
Processing Methods and Tips
| Metod | Melt Temp °C | Mold or Die Temp °C | Key Tip |
|---|---|---|---|
| Formsprutning | 190–220 | 25–50 | Dry pellets below 0.05 % moisture |
| Extrudering | 180–210 | 30–50 | Use smooth screw to limit shear burn |
| Blow Molding | 180–200 | Ambient | Great for air ducts and films |
| 3D Printing (FDM) | 210–230 | Bed 40–60 | Print slow around 20 mm/s |
Design Guidelines for TPU Parts
- Add fillets of at least 0.5 mm to reduce stress.
- Keep wall thickness even to avoid sink marks.
- Add ribs or gussets if you need stiffness.
- Use a draft angle of 1–2° for easier mold release.
- For press-fit seals, aim for 3–6 % interference.
Typical Industrial Applications
| Sector | Part Example | Main Benefit |
|---|---|---|
| Footwear | Sports shoe soles | Cushioning, long wear |
| Mobile Devices | Protective cases | Shock absorption and grip |
| Fordon | CV-boots, air ducts | Oil resistance, cold-flex |
| Medicinsk | Catheter tubing | Biocompatibility, softness |
| Industri | Transportband | High abrasion life |
Market Share by End Use (Text Chart)
Footwear ██████████████ 35 % Automotive ████████ 22 % Electronics ██████ 15 % Industrial Parts █████ 13 % Medical ███ 10 % Other ██ 5 %
Återvinning och hållbarhet
TPU can be ground and reprocessed because it re-melts rather than cures. Many plants reuse 20–30 % in new parts without major loss of properties. Suppliers also offer post-industrial or bio-content grades to cut carbon impact. If recycling is not an option, controlled energy recovery by incineration is possible.
Vanliga frågor och svar
Does TPU yellow under sunlight?
Aromatic TPU can yellow over time. Aliphatic TPU stays clear but costs more.
Is TPU safe for skin contact?
Medical-grade and food-grade TPUs are skin-safe. Confirm ISO 10993 or FDA data with your supplier.
Can I glue TPU?
Yes. Clean with isopropanol and use polyurethane or cyanoacrylate adhesives.
Slutsats
TPU material blends rubber-like flexibility with plastic processing ease. It stretches, rebounds, and resists abrasion, yet injection molds or extrudes on standard equipment. Hardness choices span soft gels to firm elastomers, covering shoe soles, gadget cases, oil-resistant seals, and more. By selecting the right grade and following good design and processing practices, engineers can unlock TPU’s full potential for durable, flexible products.
