Pertex
Encyclopedia
Pertex is a versatile, wind resistant, durable wicking fabric with more breathing ability than waterproof membranes. It is typically found in down jackets and sleeping bag
s. Originally, it was manufactured by Perseverance Mills Ltd. in Manchester, England. When Perseverance Mills was liquidated in 2005, it sold the Pertex manufacturing rights to Mitsui & Co. of Japan.http://www.cumulus-sleepingbags.co.uk/SleepingBagFeatures.htm
The breathability of Pertex comes from the fabrics use of capillary action
using denier gradients. Pertex combines two yarns with different properties. The inner yarn
has larger filaments and outer yarn has smaller filaments. Capillary action moves moisture from larger filaments to smaller filaments without passing through the air.
Imagine a bundle of very fine fibres next to an equal weight bundle of thicker fibres. The same weight of material can make more thin fibres than an equal amount of thick fibres, thus there are more thin fibres on the outer side (and a tighter weave) than there are thick fibres on the inside.
The bundle of finer fibres has greater surface over which moisture can spread - so they will evaporate moisture more quickly. The moisture from the inside is directed to the thinner fibres from thicker fibres by, again, capillary action. The driving force behind all this is the temperature difference between your own body heat on the inside and the air temperature on the outside.
Pertex is windproof because of the tight weave of the outer surface. The breathing ability of the fabric is not based on air passing through the weave of the fabric, but by moisture absorbed in the inner yarn passed to the outer yarn (which passes from the outer yarn to the outside air). Adding a waterproof coating would trap the moisture in the yarn, instead of letting it pass through the yarn and evaporate into the air.
Sleeping bag
A sleeping bag is a protective "bag" for a person to sleep in, essentially a blanket that can be closed with a zipper or similar means, and functions as a bed in situations where a bed is unavailable . Its primary purpose is to provide warmth and thermal insulation...
s. Originally, it was manufactured by Perseverance Mills Ltd. in Manchester, England. When Perseverance Mills was liquidated in 2005, it sold the Pertex manufacturing rights to Mitsui & Co. of Japan.http://www.cumulus-sleepingbags.co.uk/SleepingBagFeatures.htm
The breathability of Pertex comes from the fabrics use of capillary action
Capillary action
Capillary action, or capilarity, is the ability of a liquid to flow against gravity where liquid spontanously rise in a narrow space such as between the hair of a paint-brush, in a thin tube, or in porous material such as paper or in some non-porous material such as liquified carbon fiber, or in a...
using denier gradients. Pertex combines two yarns with different properties. The inner yarn
Yarn
Yarn is a long continuous length of interlocked fibres, suitable for use in the production of textiles, sewing, crocheting, knitting, weaving, embroidery and ropemaking. Thread is a type of yarn intended for sewing by hand or machine. Modern manufactured sewing threads may be finished with wax or...
has larger filaments and outer yarn has smaller filaments. Capillary action moves moisture from larger filaments to smaller filaments without passing through the air.
Imagine a bundle of very fine fibres next to an equal weight bundle of thicker fibres. The same weight of material can make more thin fibres than an equal amount of thick fibres, thus there are more thin fibres on the outer side (and a tighter weave) than there are thick fibres on the inside.
The bundle of finer fibres has greater surface over which moisture can spread - so they will evaporate moisture more quickly. The moisture from the inside is directed to the thinner fibres from thicker fibres by, again, capillary action. The driving force behind all this is the temperature difference between your own body heat on the inside and the air temperature on the outside.
Pertex is windproof because of the tight weave of the outer surface. The breathing ability of the fabric is not based on air passing through the weave of the fabric, but by moisture absorbed in the inner yarn passed to the outer yarn (which passes from the outer yarn to the outside air). Adding a waterproof coating would trap the moisture in the yarn, instead of letting it pass through the yarn and evaporate into the air.