Material groups

The main groups of material are cotton, polyester and nylon.
These groups are divided into further categories according to the weave, which in turn determines the finish, durability and grip of the fabric. The weaves we use have names such as Wilddobby, Dobby, Oxford and Twill.
Some of these fabrics have a special Ripstop (RS) feature. In order to increase the tensile strength while maintaining the weight of the fabric, extra strong warp and weft threads are woven into the fabric at gaps of between 2mm and 5mm.  If the fabric rips, the tear is stopped at these reinforced points, hence then name, Ripstop.
However: not everything that looks like Ripstop is actually Ripstop. Some fabrics look like Ripstop fabric without providing the distinctive Ripstop feature.

Polyester
Polyester fabric is relatively durable and does not wrinkle easily. These fabrics usually have a matt finish and are the mainstay of all types of bags and backpacks. Depending on the weave, polyester fabrics can be very resistant to wear. Salewa uses polyester material for less demanding applications where resistance to wear is not an important functional feature.
 
Nylon (polyamide 6.6)
Nylon fibres have high tensile strength and are ideal for producing very tough materials.  Nylon fabric generally has a distinctively shiny finish. Salewa uses nylon in almost all of its backpacks guaranteeing you, the user, utmost reliability.
 
Cordura
Based on nylon fibres, Cordura fabrics are much more resistant to abrasion than standard nylon fabrics, the result of a special manufacturing process. Cordura is an Invista trademark. Salewa uses Cordura in items where a high level of resistance and durability are required.

The illustrations here are original excerpts from an Invista abrasion test performed on a range of materials (the numbers in brackets refer to the number of revolutions): (top-left to bottom-right) Cordura (3,000), nylon (1,000), cotton (700), polyester (700).

Water resistance
Most materials are not particularly water-resistant without special treatment. This means that without treatment, water will eventually seep through fabric. A variety of coatings are applied to the back (usually the inside) of the fabric to increase water resistance.
PU (polyurethane) layers of varying thicknesses are the most widely used coatings. 1 PU, 2 PU, 3 PU indicates the number of coats that have been applied to the fabric. The number of layers is an indication of how water-repellent the fabric is. Depending on the weave and the type of material, water columns of between 400mm and 800mm can be achieved. Material treated in this manner can, under normal circumstances, be described as waterproof. Water will not even penetrate these fabrics in torrential monsoon rain. Nonetheless, depending on the material, water may soak the outside of some fabrics.
TPU (thermoplastic polyurethane) and TPE (thermoplastic elastomere) are also used. These types of coatings increase the water column, but also result in heavier material.
Fabrics with a PVC (polyvinyl chloride) coating are completely waterproof (water column greater than 2,000mm). In addition to the extra weight, the disadvantage of PVC coatings is that some of the softeners used in the PVC are considered a risk to health. This applies, in particular, to phthalate softeners, which are classified as harmful. Salewa therefore only uses PVC coatings in exceptional circumstances, and then we ensure that only non-harmful softeners are used during production so that possible risks to health are ruled out.

UV resistance
The sun’s UV rays bleach material and make it brittle.  Unfortunately, no material can be considered immune to these effects or capable of withstanding these types of extreme conditions. Salewa uses material with a high UV rating in its backpacks.

Weight
The weight of a material generally depends on the thickness of the threads and the density of the weave.
Denier is the unit of measurement used to measure the fineness of threads.
1 den = 1g per 9,000m of yarn
Therefore, 420 D nylon fabric is made from thread which weighs 420g per 9,000 metres.

Material use and requirements
When manufacturing its backpacks Salewa uses only the highest quality materials which meet specific usage requirements for each backpack type. This allows us to stay true to our goal of providing the best possible goods for our customers.