Qingdi™ series: slip-resistant, abrasion-resistant TPU outsoles at 60–65 Shore A
Rubber grips but wears and cannot be recycled. Conventional TPU wears well but slips. The Qingdi™ series is built to break that trade-off for safety and outdoor footwear outsoles — 60–65 Shore A, wet and dry grip comparable to rubber, fully recyclable.
The outsole trade-off
Outsole material selection has always been a compromise. Rubber delivers grip — particularly on wet tile and oily workshop floors — but it wears, it is heavy, and as a thermoset it cannot be recycled back into new soles. TPU delivers abrasion resistance, low density and full recyclability, but a standard TPU outsole is harder to make genuinely non-slip, especially wet.
The usual fix is to blend, or to accept a wear penalty for grip. The Qingdi™ series takes a different route: grades designed at the soft end of the TPU range specifically for outsole duty, so that grip, wear and softness come from one material rather than from a compromise between two.
What the series delivers
| Property | Qingdi™ series |
|---|---|
| Hardness | 60 – 65 Shore A, customisable within the band |
| Colour | Transparent and opaque versions, dyeable |
| Slip resistance | Very high / high / good by grade, in both wet and dry conditions |
| Abrasion | Superior to rubber in comparative testing |
| Processing | Injection moulding, extrusion, supercritical foaming |
| End of life | Thermoplastic — fully recyclable |
Why 60–65 Shore A
The hardness band is the design decision, not a range that happened to be convenient. Softer than about 60A and the outsole deforms under load, which costs structural stability and accelerates wear at the edges. Harder than about 65A and the material stops conforming to floor micro-texture, which is exactly where wet grip comes from.
60–65A is the window where a sole still feels comfortable after a full shift, holds its geometry under a heavy wearer, and keeps enough contact area on a wet surface to generate friction.
What slip resistance actually depends on
Slip resistance is not a single material number. It comes from the friction pair — sole compound against floor — plus tread pattern, contact pressure, contamination and temperature. A material can be excellent on dry concrete and poor on wet steel.
That is why the series is offered in tiers rather than as one grade: a workshop safety shoe on oily steel, a hiking boot on wet rock and a casual shoe on wet pavement are three different friction problems, and they should not be specified with the same compound.
Where the claim stops
The wet and dry grip comparison to rubber is measured in the supplier's own comparative testing on the compound itself. It is not a certificate for a finished shoe.
Finished-footwear slip resistance has to be certified at the shoe level — EN ISO 20345 for safety footwear, or the relevant SATRA / ASTM method for the market — because tread design, sole thickness and bonding all change the result. Treat the material data as a reason to trial a compound, not as evidence for a labelling claim.
Processing and sustainability
The grades run on injection moulding for direct-soled designs, on extrusion for sheet and slab, and through supercritical foaming where a lighter midsole-adjacent construction is wanted. Being thermoplastic, scrap and end-of-life soles can go back into the process rather than to landfill — which is the one advantage rubber structurally cannot match.