| Materials | Nylon 6-6 | Polyester | Kevlar | Dyneema |
| Melting Point | °C | °C | °C | °C |
| Mass Density | 1.15 g/cm³ | 1.37 g/cm³ | 1.44 g/cm³ | 0.97 g/cm³ |
| Friction Resistance | Good | OK | Excellent | Self lubricating |
| Stretch | High | Low | Very Low | Creeps |
| Colorfastness | Superior | Great | Not | Not |
| Chemical Resistance | Not good | Excellent | Good | Excellent |
| Arresting Force | Excellent | Good | Not good | Not good |
| UV | Fades easily | OK | Will damage | Excellent |
| Arctic Conditions (sub -46 degrees C) | Poor when wet | OK | Excellent | Not good |
| Cut Resistance | Good | OK | Excellent | Not good |
| Strength | Good | Good | Excellent | Superior |
| Misc | Excellent for use | Most common | Rough and tough | Amazing product |
Materials are a funny thing, in our industry we use man made fibers and the two most common are Nylon (comes from NY-London in a time it was going to replace Silk and is a trademark of Dupont) and Polyester. Nylon is a extruded from polyamide and polyester is well a polyester.
Yarn for yarn Nylon feels soft and silky, Polyester is more rough both do a great job as products in the climbing industry and only a few will notice the differences but different they are. Especially in durability and stretchability. Nylon is much more durable and it stretches when using it so Nylon it is, right? Nope Polyester doesn’t absorb water, UV, availability, etc. It also has lots of good characteristics that the shift from Nylon, with its higher price, to Polyester has been happening for the last 10 years and with good reasons.
Kevlar® is a product from Dupont and places itself in the Aramid family just like Nylon. It does not need an introduction as many of us know it from bullet proof vests and fire rated equipment. Especially for the last application it is the go to product for harnesses and lanyard. Although though to work with, try cutting it for instance, it is an excellent product we have used for special projects such as the Devil’s gate harness.
Kevlar® is chemically stable under a wide variety of exposure conditions; however, certain strong aqueous acids, bases and sodium hypochlorite can cause degradation. For the full list go to this site.
Dyneema is a tradename and a product from Aviant (formerly DSM). Dyneema is the first and closest we as human have come to the spider fibre like materials and it keeps on being developed. Where it was impossible to die the white fibers, hence the reason why the Dyneema slings are mainly white, although DSM is constantly tinkering around with the product we now even have colour options, although not perfect it is a good first attempt.
Dyneema is produced from ultrahigh-molecular weight polyethylene and is super strong. Therefore it allows designers to create thin slings but you do have to ask yourselves what will happen during a fall as Dyneema is bad for absorbing forces unlike Nylon.