What is semi static and what is dynamic rope?
The word static indicates that there is no stretch in the rope. (Not used in outdoor sports)
Semi static rope
With semi-static rope, the elongation is minimal (in accordance with EN1891) but is definitely noticeable, especially during activities on long lines (for example, climbing a line of 50 meters).
Thanks to this stretch in the semi-static ropes, forces released during a fall are sufficiently absorbed.
The semi-static lines are used for rope access activities, working on flat and/or sloping roofs, as a safety line in vertical structures, during rescues, as a descent line (abseiling), etc.
For the difference between Type-A and Type-B ropes on semi-static lines, see: the CanyonZone Knowledge Base.
Dynamic ropes are mainly used in outdoor sports. These dynamic lines / climbing ropes contain so much stretch that they can often absorb the full fall of a climber without the intervention of, for example, fall dampers.
Dynamic climbing rope consists of a nylon core, around which the actual rope is braided. The sheath (which is usually colored) is still around it, which protects the rope.
Way of production of ropes
Rope is made by twisting or braiding (twisting) several strands of synthetic fibers together to get a stronger and more durable material.
Nylon fiber will stretch. This property in combination with higher rotational speeds in the core bundles allows dynamic ropes to stretch and acquire their dynamic properties. Polyester/Dyneema/Technora fibers stretch very little or not at all and are used in combination with lower twist rates in the core bundles when little/no stretch is required. e.g. Dynamic rope = 100% nylon with multiple core bundles with high twist. Static/low elongation = low elongation fiber sheath around low elongation fiber, low twist rate core bundles.
For more see: Information about rope: choice and maintenance