Material facts

We use a variety of materials for the products in the Swedish Rope program. Some of these are briefly described here:

SYNTHETIC FIBRES

Polyester:  Density 1.38. Melting point: approx 260 °C.

Polyester  has very good UV-resistance, very good abrasion properties and good resistance to acids.

  • Polyester multifilament consists of many thin solid fibers of polyester, forming coarser polyester multifilament yarns.
  • Spun polyester consists of shorter polyester fibers, spun together to form yarns with a matte finish which gives it higher friction properties than the polyester multifilament yarns, yet loosing some strength.

Polyamide: Density 1.14. Melting point: approx 220-250 °C.

There are various polyamide brands on the market , such as ”Nylon” (=”Polyamide 6.6”) and ”Perlon”  (=”Polyamid 6”) which are the more common brands. All brands and types of polyamide have different properties, although good elasticity (whick gives very good shock absorbation properties), good strength and good UV-resistance (howeer not as good as the polyester) distinguishes all polyamide fibers. In the Swedish Rope program polyamide multifilament is the more commonly used fiber. Polyamide is resistant to alkalis but not to acids.

Polypropylene:  Density 0.91. Melting point: approx 165 °C.

Products made from polypropylene floats due to its low density. UV-resistance is average but can be improved by chemical additives in the production of the fiber. The material is resistant to most alkalis and acids. Polypropylene is produced as various types of fibers where PP split film is the most common. It is produced by spraying melted pp granules on to a film (or “foil”) which is then divided into narrow stripes that are twisted together into a yarn.

Other forms of PP yarns are PP monofilament (fiber diam > 0.1mm) and pp multifilament (fiber diam < 0.1mm). Polypropylene rope exists in a variety of colours but is more common in blue (PP blue).

Polyethylene: Density 0.95. Melting point: approx 135 °C.

The polyethylene fiber occurs mostly as monofilament in the production of cordage. Polyethylene floats, just as the PP fiber. It has slightly less strength than the polypropylene but has better abrasion properties an UV-resistance. Colour: mostly orange.

Danline: Density 0.92. Melting point: approx 145 °C.

This fiber, often light green in colour, is a “modified PP fiber“ and has many names on the market, one is “Poly-Steel”. Danline floats and has better UV-resistance and higher breaking load than rope made from polypropylene (about 20% higher).

HMPE (= ”High Modulus Polyethylene”):  Density 0.97. Melting point: approx 140 °C.

A highly processed polyethylene fiber in which high strength and extremely low elongation (approx 2-4%) has been achieved. Often used as core for braided lines when high breaking load, light weight and low elongation is desirable. Common brands are “Spectra” and “Dyneema”.

Aramid (= ”High Modulus Polyamid”):  Density  1.41. Does not melt.

A highly processed polyamide fiber with very high breaking load and low elongation. The most common brand is “Kevlar”. The kevlar fiber is sensitive to sharp breakings and has low UV-resistance. Used mainly as core for braided lines, sometimes mixed with HMPE.

HMP (= ”High Modulus Polyester”):  Density 1.4. Melting point: approx 280 °C.

A highly processed polyester fiber with high breaking load, low elongation and virtually nonexistent “creeping” (=when the fiber becomes ductile and will not regain its former length after having been stressed).

Used mainly as core for braided lines. Most common brand on the market is “Vectran”.

NATURAL FIBERS

BAST FIBERS

Hemp (”Cannabis sativa”):  Density: approx 1.4. Does not melt. Does not float.

This fiber is extracted from the bast on this plant and is processed into yarn by following an extensive procedure, including: “retting, carping, scutching, hackling and spinning”. Used in the process of making ropes and lines.

Flax (”Linum usitatissimus”):  Density: approx 1.4. Does not melt. Does not float.

This fiber resembles the hemp fiber but is softer and stronger. Used mainly in the production of thinner twines and cords and as an intermixture for hemp yarns to make them smoother and stronger.

Jute (”Corcharus capsularis”, ”Hibiscus sabdarifa”, m fl): Does not melt. Does not float.

Bast fiber from tall bushes. Lower strength than both hemp and flax. Are used in horticulture twines and for decorations.

LEAF FIBERS

Manila (”Musa textilis”):  Density: approx 1.4. Does not melt. Does not float.

This fiber is extracted from the leaves of a plant closely related to the banana plant. The fiber is considerably harder and more rigid than hemp but has approximately the same strength and is less sensitive to decomposition. Ropes made from manila are used for lifeboat- and pilot ladders.

Sisal (”Agave sisalana”): Density: approx 1.3. Does not melt. Does not float.

Extracted from the leaves of different species of Agave.

SEED FIBERS

Coconut fiber: Does not melt. Floats.

Sometimes referred to as “grass”, extracted from the straw-like pilosity on the coconut shell. These fibers are relatively hard and rough. Used to make rope fenders and various types of maritime handicraft.

Cotton: Does not melt.  Does not float.

This fiber is extracted from the seeds of the “Gossypium”-bushes. A very smooth and soft fiber suitable for production of both coarser ropes and thinner lines. Today the ropes are used mainly for decorations, while cotton twines and cords are very common in macramé handicraft and warp.

 

 

REMEMBER that specified breaking loads for all goods in the directory apply when goods are new!

Careless handling, wind, weather and time have a negative effect on the ultimate load.

Knots can reduce the breaking load of a rope by  >50%.

Also, splices reduce the breaking load approximately 10%.