TPU Supplier China | Polyester & Polyether TPU Grades

When stepping up to TPU pays for itself

TPU costs more per kilo than either polyolefin elastomer and it has to be dried before processing, so the switch has to be earned. It earns its place in four situations:

The part wears. Wheels, soles, cabling, belting and seals that lose material against grit or steel.
The part carries load and must spring back. Where compression set, not softness alone, decides service life.
The part flexes in the cold. Outdoor, cold-chain and winter sports goods judged on low-temperature flexibility.
The part meets oil, grease or fuel. Resistance olefins do not offer.

If none of those apply, stay down the ladder: a TPE compound will normally give the required soft touch for less, and a POE will do its job inside somebody else's compound.

Choosing between polyester, polyether and polycaprolactone

The branch, not the hardness number, decides whether the part survives. Every RFQ should name one.

Branch	Strengths	Watch out for	Duty it suits
Polyester (ester-based)	Abrasion, tear strength, load bearing, oil and fuel contact	Hydrolytic attack in warm wet service; must be dried before processing	Soles, wheels, hoses, cable jacketing, industrial belting
Polyether (ether-based)	Hydrolysis and microbial resistance, retained low-temperature flexibility	Lower abrasion and oil performance than ester; availability varies by producer	Marine, outdoor, cold-chain, breathable film, medical contact
Polycaprolactone (PCL)	Toughness closer to ester with hydrolytic stability nearer ether	Not a stock item at every compounder — confirm availability and lot size before designing in	Seals, gaskets and soft-touch parts needing both

Two suppliers quoting "TPU" at the same hardness may be quoting different branches. Make them state the branch on both the quotation and the packing label.

Drying and hydrolysis: the failure nobody prints on the datasheet

Ester-based TPU absorbs moisture from the air. Process it damp and the molecular chain is cut during melting — the part looks acceptable but has lost strength, and the damage cannot be undone. In service, hot and humid conditions attack the same chain over months rather than minutes.

Have the supplier state the drying schedule — time, temperature and dew point — on the TDS, not in an email.
Ask how the material is shipped and sealed: moisture-barrier liner and intact bag seals matter more than pallet wrapping.
Re-dry regrind separately. Sprue and scrap take up more moisture than virgin pellets.
Do not let melt sit hot. Ask for the maximum residence time at processing temperature.
For wet or tropical service, start the conversation on ether grades and ask for hydrolysis test evidence on the exact grade.

What to write in the RFQ and ask to see

Branch and grade code — ester, ether or PCL, fully identified
Hardness and test standard — your Shore requirement and which scale you measured it on
Abrasion result — the test method used, plus the load and wheel specification
Tensile set and rebound — at your service temperature, not at room temperature
Compression set — time and temperature of the test, matching your service conditions
Hydrolysis and UV evidence — for outdoor, marine or heated wet duty
Drying schedule and residence limit — so your moulder costs the job correctly
Documents — lot COA with measured values, TDS, SDS, REACH SVHC and RoHS statements, EU 10/2011 or FDA 21 CFR declaration for food contact, and an IMDS entry for automotive supply

Where TPU sourcing goes wrong

Buying on hardness alone. Hardness says nothing about rebound, wear life or compression set.
Letting an ester grade into a wet, warm application. Specify the branch, or ask both suppliers to quote both branches and compare.
Assuming a polyolefin drying routine is enough. TPU generally needs desiccant drying and a shorter hot holding time — confirm with the grade owner.
Changing branch without re-qualifying the process. Ether and ester grades do not share the same drying or melt window; re-qualify the moulding job when the branch changes.
Expecting TPU to toughen another resin. That is a compounding job for a modifier; start from POE.
Assuming soft-touch overmoulding works on any substrate. Bonding is substrate-specific; see the TPE page for the bonding question, and insist on trials on your own substrate.
Re-running regrind without a written ceiling. Agree a regrind ratio per part and hold it — see the regrind control guide.

Frequently Asked Questions

When should I stay with TPE instead?

When soft touch is the whole requirement — grips, handles, overmoulded pads — and abrasion is not the failure mode. TPE is easier to process and generally cheaper; choose it until the duty proves it out. Compare routes on the TPE page.

When is TPU simply the wrong answer?

When you need a modifier inside another resin rather than a finished elastomer part. Impact modification of PP or PE is a compounding specification for POE, not a TPU purchase.

Do I need to understand TPU versus TPEE?

For continuous heat, fatigue cycling or hydrolytic service, yes — the two are not interchangeable. That comparison is written up separately in TPU vs TPEE: heat, fatigue and hydrolysis.

How is the choice between TPE and TPU decided?

On wear and load, then on cost. The full soft-touch versus wear-resistant decision tree is in TPE vs TPU: choosing between soft-touch and wear-resistant moulding.

Will TPU bond to my substrate?

Sometimes, and only after trials. Bond strength depends on the substrate, the melt temperature and the shot timing. Ask each supplier to run bonding trials on your actual substrate before quoting a production price.