Rope material introduction of climbing rope.The earliest ropes are generally made of natural fibers. There are several commonly used natural fibers:
Derived from the stem of a hemp coke, this plant is a close relative of banana. This type of rope was used in early mountaineering and sailing activities. In 1864, the British Mountaineering Club selected Manila hemp with a diameter of 10 mm and a weight of 75 grams per meter as the first choice for mountaineering. The strength of this rope is almost the same as that of current mountaineering ropes. The strength is the same, and it will be stronger when wet.
Mainly used to make cheap rope, its strength is 20% lower than that of Manila hemp, and its flexibility is also worse.
This natural fiber has high strength and is suitable for sailing. However, tar treatment was required to maintain its durability in seawater. Later, Manila hemp was used more often, but Italian hemp has always been a common rope material for mountaineering.
A large number of research and development and application of synthetic fibers have given more choices in the production of ropes. A batch of high-quality and low-cost synthetic fiber materials have gradually replaced traditional natural fibers. Currently, the main materials used are:
Since the DuPont Carothers research team invented nylon in 1935, it has quickly become the first choice for mountaineering ropes because of its tensile properties and good corrosion resistance after loading. Nowadays, many types of nylon have been developed. The most commonly used for mountaineering is nylon 6, which has good toughness, stretchability and elasticity, so it is very suitable for power rope. Nylon 66 has a high melting point and little stretch, so it is suitable for static ropes for cave exploration, rescue and descent.
It was successfully developed by British scientists in 1941, and its chemical name is polyethylene terephthalate. The static extension of this material is very small, and it does not lose its strength when exposed to water (nylon will lose about 20% of its strength when exposed to water), so it is very suitable for sailing ropes, and also a large number of static ropes for mountaineering and cave exploration. Anti-ultraviolet and abrasion resistance. Generally, the outer protective skin of the rope is made of polyester material, and the inner rope core is made of nylon material. Its disadvantage is that the specific gravity is a little bit larger, which is 1.38, while nylon is 1.14. So the rope made of this material is a bit heavy.
It was discovered by an Italian chemist in 1954 that it can be extracted from oil and natural gas, with low cost, stable chemical properties, good extensibility and strength. And the specific gravity is low (0.91), it is the lightest rope material, so it can float on the water, suitable for water rescue rope, water skiing traction rope, long time in the water will not absorb sailors and lose strength. Its shortcoming has a low melting point (165 degrees), it loses all its strength at 93 degrees, and its abrasion resistance is average. It will also lose its strength when used below minus 29 degrees, and it is almost resistant to ultraviolet rays. Therefore, it is not suitable for use in high temperature, severe cold, and high friction environments. Not suitable for static rope.
There are basically two types of high density and low density. Low density polyethylene is not suitable for ropes. The properties are similar to polypropylene. They are all polyolefin polymers. They have a very low specific gravity (0.95). The chemical reaction is slow and waterproof. They are all similar. Because of the smooth texture, the knots are easy to tie. Disconnected, its melting point is lower (140) and the working temperature is 65 degrees, so it is not suitable for general rope. But his stability at low temperatures is very good, and it can maintain good softness at minus 73 degrees, so it can be used as a sled harness.
In 1964, DuPont successfully developed it. In 1975, Kevlar began to be applied to body armor, and then gradually promoted and applied to other products. The weight and diameter of the rope made with it is only half of the traditional rope, but the strength is the same, but its extension Ability and shock absorption ability is poor, so it is necessary to add a polyester jacket to protect against ultraviolet rays and abrasion. Due to the completely linear molecular structure, the longitudinal strength is high, and the strong strength is weak, resulting in poor abrasion resistance, after knotting and bending The strength loss is great. So it is not suitable for outdoor rope. Now the newly developed Technola material has solved this problem, but the cost is three times that of ordinary ropes.
Dutch scientists produced a colloid that can be stretched and spun by melting polyethylene. This process produces a high-modulus ultra-high molecular weight polyethylene fiber, which is 10 times stronger than steel by the same weight. It retains many characteristics of polyethylene, with a specific gravity of 0.97, and also has super abrasion resistance, will not be degraded in the sun, but it also inherits a low melting point (147 degrees), poor shock absorption capacity, and weak points of a smooth surface, so The tied knots are easy to loosen. Generally, three fisherman knots are used when connecting, or the two ends are stitched together. Although it has shortcomings, its small size, high strength, and light weight are still very suitable for climbing ropes. The new generation of high modulus polyethylene 8 mm braided rope has a strength equivalent to 18 mm nylon rope and only half the weight of nylon rope.