SkinCare 202 - Armadillo Merino® Protection, Performance and Comfort
Having covered the basics in ARMATECH101, here we look at Protection, Performance and Comfort in more detail.
Protection: No Melt - No Drip & Natural fire resistance
Armadillo Merino® fibre has naturally occurring flame resistant properties that make it suitable for use in baselayer clothing. This flame retardancy arises from its unique chemical structure (a high nitrogen content (14%) combined with a high relative moisture content), which displays the following beneficial properties:
- A very high ignition temperature (570-600°C)
- Doesn’t melt or stick upon burning, rather, it forms an insulating char
- Self extinguishing
- A high Limiting Oxygen Index (20- 25%) – with the LOI being a measure of the minimum % of oxygen required to sustain combustion
- A low heat of combustion
- A low rate of heat release
- Evolution of less smoke and toxic gases than formed during combustion of most synthetic fibres
A comparison of Merino fibre with other important textile fibres, demonstrates superior performance across virtually all parameters measured.
Ultraviolet (UV) radiation is a component of the solar radiation that comes from our sun. The potential for a fabric to protect its wearer from ultraviolet radiation is described as its Solar or Ultraviolet Protection Factor (SPF or UPF). UPF relates to the time taken before human skin begins to redden after exposure to ultraviolet light – and is usually measured on a scale of 0-50.
The greater the amount of radiation able to pass through a textile the lower the UPF. The most important of the factors influencing UPF are summarised below:
Fibre type (wool typically has a much higher UPF than synthetic fibres).
- Fabric density (denser structures confer a higher UPF).
- Degree of stretch (with the UPF being lowered in a stretched state).
- Fabric colour (with the UPF factor dependent on the amount of dyestuff present and the chemistry of the dye itself – darker colours usually result in a higher level of protection).
- Whether the fabric is wet or dry (UPF decreases markedly when wet).
- Presence of UV absorbing finishes and/or optical brightening agents
- Garment design
Research has shown that wool absorbs radiation throughout the entire UV spectrum, whereas untreated cotton, nylon, acrylic, and silk are poor absorbers of UV. Due to this, Armadillo Merino® has a UPF of greater than 40.
UPF Factor for Summer fabrics (mean weight 158 g/m2)
Protection: Acid Resistance
Unlike many synthetic fibres (e.g. nylon, rayon etc.) and cotton, merino fibre demonstrates very a high resistance to acids. In fact, many of the wet treatments imparted to merino fibre and fabric (dyeing, shrink-resist and flame resist treatments) rely on exposing merino fibre to low pH in order to lock such agents within the fibre and achieve very high levels of fastness.
Protection: Chemical Residues and Aerosol Penetration
Because of its unique internal and surface chemistry (in particular, its hydrophobic cuticular scale structure) wool fabrics have been shown to be more resistant to penetration of aerosols such as insecticides etc. than those made from synthetic fibres such as nylon, acrylic and rayon.
Performance: Physical Exertion
Energy is expended as the body attempts to maintain equilibrium. Sweating is the tool the body uses to regulate its temperature as the process of evaporation of sweat from the skin cools the skin surface. Energy is expensed in pumping blood to the extremities in hot conditions to increase the likelihood of head dispersion over a greater surface area. In cold conditions, the body takes to shivering to maintain heat.
Studies at the Clothing and Textile Sciences Department, University of Otago, New Zealand have demonstrated that core temperature remains more stable during and post physical activity when wearers wore 100% Merino wool garments as opposed to 100% polyester.
In addition, heart rate remained closer to the norm, indicating that lower levels of exertion were required to achieve the same level of performance when wearing Merino wool garments, in both hot and cold conditions.
Performance: Odour Suppression & Easy care
Body odour arises as the result of the build up of bacteria and microorganisms on the skin and/or in worn apparel/hosiery. One of the key contributing factors to the build-up of bacteria and body odour is sweat on the skin surface. The human body has more than 3,000,000 sweat glands, which continually secrete moisture. Sweat by itself does not have any odour. However, if sweat remains on the skin for a period of time, bacteria are likely to proliferate, creating the body odour that many find offensive. Such body odour is due largely to volatile fatty acids produced by these bacteria as a waste product.
Performance athletes the globe over will attest to the odour suppressing capabilities of Merino. When apparel fabrics were examined by researchers at the University of Otago they found fabrics made of merino fibre exhibited a significantly lower propensity for odour emission after wear than polyester fabrics of a similar weight and construction.
Propensity for odour emission by fabrics of similar construction
There are many aspects to clothing comfort but the most popular merino attribute relates to the fabric’s ability to manage heat and moisture flows. This has a major influence on the thermal state of the body and on the wearer’s perceptions of their physical condition.
Our body’s mission is to keep our core temperature as stable as possible through the vast range of exertion and climatic changes to which we are exposed. Merino apparel’s natural buffering capacity helps the body maintain a stable core temperature as it assists the process of heat loss in hot conditions and keeps the wearer warm in cool and damp conditions.
*NOTE: one touch of modern Armadillo Merino® wool fabrics will set your mind at ease in regards to its softness.
Comfort: When it is Hot
The degree of warmth felt by the wearer will depend on how well fabric moves heat and moisture away from the skin. The release of water vapour, which often condenses to liquid sweat, is the body’s way of releasing heat.
Merino fibre has a hydrophobic (water repelling) exterior and hydrophilic (water loving) interior that means it has the ability to absorb and desorb moisture and to gain and release heat depending on the external and internal environment - thus buffering the wearer against environmental changes and increasing the time before the onset of liquid sweat and fabrics feeling wet.
Comfort: When it is Cold
In the cold we attempt to trap more air (the most effective insulator) around the body by adding clothing layers. The thermal resistivity (R) of a fabric is a measure of its insulating properties – and hence of its relative warmth. Due to the natural crimp of the fibres, Merino fabrics and hosiery have an inherent bulkiness or loft as the fibres are unable to pack together too closely in the yarn structure. The resilience or elastic recovery of the Merino fibre allows this bulkiness to be maintained over time.
Comfort: Natural Buffering
Merino wool has an important differentiator in that an appreciable quantity of heat is also generated as water is absorbed into the fibre. In an apparel or hosiery application this prevents the wearer from chilling in wet, cool conditions or post exertion. In hot conditions the reverse effect occurs, affording a natural means of buffering the body’s microclimate.
This heat is then lost again as the Merino garment dries – effectively warming and cooling the wearer of apparel when needed the most, thus assisting in the maintenance of overall user comfort.
Heat of sorption of wool and other synthetic fibres.
Comfort: Skin Health
Wool’s hygroscopic properties mean it is able absorb a significant quantity of moisture, thus minimising/delaying any increase in the skin coefficient of friction that might result in user discomfort, blisters, etc.
Top read more
ArmaTech 301 - Why soldiers should wear Armadillo?
ArmaTech 302 - Armadillo Merino® as essential PPE for firefighters
ARMATECH: 303 - What is the most effective baselayer system for safety, performance and wellbeing?