General Information on Dyneema
Invented 1979 in the Netherlands and in commercial production since 1990. Dyneema® is both the worlds strongest fibre and the only HMPE fibre scientifically engineered to overcome abrasion, bending fatigue, compression, and creep fatigue. It is up to 15 times stronger than steel weight for weight.
Technical Specification on Dyneema
Material: Ultra-high-molecular-weight polyethylene.
Abbreviation: HMPE (Ours is DY)
Specific Gravity: 0.96 Floats
Resistance to Acid: No reaction
Resistance to Alkali: Very resistant
Resistance to Solvents: Minimal reaction
Resistance to Heat: Up to 70°C Short exposure (Low:-85°C)
Resistant to UV: Excellent
Resistance to abrasion: Excellent
Affected by Moisture: No
Stretch: Very Low (3.8% at break). Creep: At high loads
Knot holding: Fair but weakens the rope by up to 70%
Washing temperature: 30°C
Approximate Melting Point: 150°C
A Word of Warning
Dyneema ropes are immensely strong but that doesn't necessarily mean they are a better choice for all applications. If a falling weight is arrested by a nylon or polyester rope, the rope will stretch and absorb a great deal of the shock loading. If a falling weight is arrested by a Dyneema line there will be virtually no stretch and huge impact forces are liable to break the line or tear out the anchor point.
I have seen many examples of "weaker" ropes successfully arresting falling weights while much "stronger" Dyneema ropes have failed. On the plus side, there will be no whiplash which is why many tug drivers are choosing Dyneema for their tow lines. So choose Dyneema when the loads are constant and the lack of stretch is advantageous. It can also be useful because of its smaller diameter to strength ratio.