Rieter

Moisture

Index

Almost all fibre material contains a certain quantity of water. The magnitude of this water proportion depends upon the raw material and the environmental conditions. Distinctions are drawn, for example, between the following criteria:

  • moisture take-up from the air
  • water-retention capability after soaking and centrifuging
  • water take-up after soaking and drip-draining.

Moisture take-up and water-retention capacity are dependent practically only upon the raw material, while in relation to water take-up the design of the textile also plays a major role in determining the result.

In the case of man-made fibres, there is a clear relationship between the ability of the raw materials to take up water and their strength in the wet condition. The more water a fibre can hold, the greater is the difference between wet and dry strength. The relative wet strength is generally given as the measure of this effect, and is expressed as a percentage of the dry strength.

Depending upon their field of use, fibres with a higher or lower moisture take-up will be required, e.g. high hand towels, underclothing; low - bathing costumes.

In relation to clothing, however, it is not only the moisture take-up that is important but also the ability to transport moisture and wettability. Both properties have a strong influence on wearability. They depend upon fibre surface area and the capillary effect on the fabric. Thus, although PES has a low moisture take-up, good moisture transport can be reached by means of appropriate apparel design (Table 3).

Table 3 – Behavior in relation to water