1. What's the difference between UHMWPE & HMPE
UHMWPE is short for Ultra-High-Molecular-Weight Polyethylene — a linear polyethylene with a molecular weight above 1.5 million. It was first produced industrially around 1957.
HMPE (high-modulus polyethylene) is the industry term for ropes, slings, and cables made from UHMWPE fiber. In the sling world, ISO 18264 uniformly uses the term HMPE.
Common brand names of this fiber are listed below. They are all UHMWPE/HMPE fiber, just different brands. When buying, check the standard and the certification rather than relying on the brand name.
| Brand | Producer | Typical grades |
|---|---|---|
| Dyneema® | Avient (formerly DSM) | SK75, SK78; DM20 (low-creep grade) |
| Spectra® | Honeywell | Spectra 1000, Spectra 2000 |
| Tekmilon® | Mitsui Chemicals | HM-1500, HM-2000 |
2. Why it's so light yet so strong
The strength comes from the structure: UHMWPE's molecular chains are extremely long, and high-orientation drawing builds high crystallinity — the chains are straightened and packed tightly, so they hardly slip. That is why both breaking strength and modulus are very high while density stays very low.
Light: density about 0.97 g/cm³ — one of the lowest densities among commercial fibers and the only high-performance fiber that floats on water; about two-thirds that of aramid and half that of carbon fiber. As a composite it is roughly 20% lighter than aramid and 30% lighter than carbon-fiber laminates.
Strong: its specific strength (strength per unit weight) ranks among the highest of all commercial fibers. For slings: at the same rating, an HMPE sling weighs only about 1/8 of a steel-wire rope with equal capacity.
| Property | Value |
|---|---|
| Density | 0.97–0.98 g/cm³ (floats in water) |
| Strength | 20–40 cN/dtex (among the highest of all fibers) |
| Modulus | 500–1500 cN/dtex |
| Elongation at break | 1.0–6.5% |
| Melting point | 135–145 °C (DSC peak ≈ 144 °C) |
| Max. usable temperature (fiber-level data) | 80–100 °C |
3. What these properties mean for slings
The above is about the material itself. This section is what buyers care more about: what each property gives you once it goes into a sling.
- Light & floats → easier to move around on site and less effort for operators; offshore, if a sling accidentally falls overboard it can float back up for recovery. Weight on its own is a key selection factor for offshore jobs.
- Low elongation & steady load → the lift is more controllable, the shock is smaller, and the load stays more stable.
- Impact resistance & energy absorption → handles the shock at the moment of lifting, plus the dynamic wave loading that wind turbines and vessels take at sea. High energy absorption absorbs the impact and lowers the risk of breakage.
- Chemical resistance → not easily corroded by oil, acids/alkalis or marine saltwater: after 7 days in 10% hydrochloric/nitric/sulphuric acid, strength retention is 100%; after 6 months in common media such as seawater, detergent and kerosene, strength retention is still as high as 100%.
4. Limits to know before you buy
Temperature is its biggest weakness. UHMWPE melts at about 144 °C, and the fiber-level data shows rapid strength loss as sustained temperatures approach 80–100 °C. It tolerates brief excursions above its limits, but not sustained high heat. The table below shows how strength / modulus / elongation hold up with temperature and time:
| Temperature (°C) | Time (h) | Strength retention (%) | Modulus retention (%) | Elongation (%) |
|---|---|---|---|---|
| 23 | ∞ | 100 | 100 | 100 |
| 60 | ∞ | 75 | 80 | 180 |
| 80 | 1 | 100 | 100 | 100 |
| 80 | 4 | 100 | 100 | 100 |
| 80 | ∞ | 50 | 55 | 300 |
| 100 | 1 | 100 | 100 | — |
| 100 | 4 | 100 | 100 | — |
| 100 | ∞ | 30 | 30 | <80 |
| 120 | 1 | 85 | 80 | — |
| 120 | 4 | 50 | 80 | — |
∞ means long-term.
Creep: UHMWPE elongates slowly under sustained load, but only a little — under a sustained load of 0.011 cN/dtex (about 0.1 g/den) at 35 °C, elongation is about 0.05%, 0.2% and 0.4% after 10 h, 100 h and 1000 h. Because elongation is so low and dimensional stability is good, it suits hoisting duty well; still, long-term continuous suspension is a boundary to keep in mind — unload the sling promptly once the job is done.
- Light resistance: UHMWPE is among the most light-resistant organic fibers — after 24 months of light exposure, strength retention stays above 50%. Even so, for long-term storage, keep it in the shade and out of direct sunlight and UV, to preserve its full service life.
- Bottom line: the material's limits are exactly why ISO 18264 mandates design factors, covers and inspection requirements for HMPE slings.
5. FAQs
Should I write “UHMWPE” or “HMPE” when I order?
Same material — at the fiber/raw-material end it is usually called UHMWPE, while sling product literature per ISO 18264 generally uses HMPE (e.g. HMPE eye-and-eye / endless roundslings). So don't worry about the wording. What matters is checking certification and ratings — see also Precautions for Procuring HMPE Slings.
What temperature range can an HMPE sling be used in?
HMPE slings are typically rated for use and storage at −40 °C to +70 °C. Above that range the fiber softens and loses strength, so keep slings away from heat sources such as hot pipes, welding arcs and steam lines; for jobs that must withstand higher heat, consider an alternative such as steel-wire rope. Note the distinction: the 80–100 °C figures in Table 2 describe the raw fiber, while the −40 °C to +70 °C rating applies to finished HMPE slings per ISO 18264:2022.
Further reading
- HMPE Slings: The Complete Procurement Guide for Offshore Projects
- HMPE Slings in Offshore Wind and Marine Engineering
- Precautions for Procuring HMPE Slings
- HMPE Slings for Heavy Lifting, Product Page
Data sources and disclaimer: the performance data in this article is quoted from an academic monograph for reference and buyer education only. Actual orders and use should follow the lifting plan, the sling manufacturer's certification and ISO 18264.