UHMWPE yarn is truly a cut above. UHMWPE is an acronym for ultra-high molecular weight polyethylene, which is often known by the brand names “Dyneema” and “Spectra”. It is different to the similarly named HDPE (high density polyethylene). UHMWPE is so called because it has very long chains of repeating monomers, with over 200,000 carbon atoms in a chain forming a single macromolecule (a very large molecule).
Benefits of UHMWPE Yarn
UHMWPE yarn has particularly high tensile strength, abrasion resistance and chemical resistance. In addition to excellent abrasion resistance, UHMWPE yarn has an exceptionally low coefficient of friction, meaning that it slides over surfaces far easier than other comparable yarns. They also have significant strength/weight ratio benefits over steel wire.
UHMWPE Yarn Recycling
UHMWPE is also highly recyclable; two methods of recycling are available for UHMWPE yarns. The first is the standard recycling process for such thermoplastic yarns, which involves melting down the yarn into pellets which can be reheated and re-extruded. The second is for the UHMWPE yarn to undergo the recycling process like that used by Tay for its innovative stretch broken spun yarns, producing a unique type of yarn which is soft to the touch like a natural fibre which can have higher abrasion resistance than the continuous filament yarn.
Some Caveats to Consider
While UHMWPE yarn has many upsides, there are some caveats to consider. The first is that UHMWPE is not well suited to high temperature applications; the melting point is around 150°C, with degradation in performance occurring beyond 70°C, so it is not recommended for use at such temperatures. The other is that gram-for-gram, UHMWPE can be more expensive, although this has to be weighed up against its higher strength at a given weight relative to many other types yarns, meaning less is required to achieve a similar tensile strength to another yarn.
Examples of UHMWPE Yarn Uses
Ultra-high molecular weight polyethylene yarns are used across many industrial and leisure activities owing to their highly sought-after properties. UHMWPE is a popular choice for climbing ropes, as the ropes themselves have significant weight savings over traditional used nylon and polyester ropes. These weight savings are highly appreciated by any climber, but they do also have other benefits over other climbing ropes. The high abrasion resistance means that ropes made with UHMWPE can be used for longer, as the friction between the ropes and the attachment points and rock surfaces do not wear out the rope so quickly.
UHMWPE is similarly sought after for use in sailing; the high abrasion resistance, water-repellence, and enviable tensile strength mean that they are well suited to the harsh treatment that sailors put their boats through. They are a popular choice form the smallest sailing yachts to the largest industrial ships. UHMWPE rope is also resistant to any oils that may be used on a boat, meaning that an unfortunate spill of a lubricating oil, for example, will not cause unseen and dangerous damage to the rope.