Garments Play An Important Role In Protecting Our Skin From This Threat
First of all a short examination of UV rays: the ultraviolet radiations can be divided into three regions: UVA (315 to 400 nm), UVB (280 to 315 nm), and UVC (200 to 280 nm). UVC are totally absorbed by the atmosphere and does not reach the earth. UVA cause little visible reaction on the skin while UVB are most responsible for the development of skin cancers.
The Fabric is composed of fibers for absorbing, reflecting or scattering radiant energy, and the garment is able to absorb or block most of the incident radiant energy and prevent it from reaching the skin.
However, a fabric's ability to block UV rays is dependent on several parameters: fiber chemistry, fabric construction (porosity, thickness and weight), UV-absorbers and other finishing chemicals that may have been applied to the textile material.
Fabric Construction And UV Protection
Porosity, weight, and thickness are the most important parameters under the fabric construction category. Numerous studies have concluded that fabric porosity (openness) is the best predictor of UV transmission through white and undyed fabrics with fiber chemistry coming in second.
Colour and UV protection
The colour of a fabric is a very significant factor in preventing UV radiation transmission through a textile because dyes act as effective UVabsorbers. The studies related to the effect of colour on UV radiation transmission state that, for fabrics of identical weight and construction, darker coloured fabrics are more effective UV absorbers than lighter shades.
Additives and UV protection
Sometimes fabrics have to be treated with additives in order to improve their UV protection abilities. The simplest type of additive, albeit a very effective one, is the delusterant pigment TiO2 which acts as an UV absorber. Since TiO2 is incorporated during fiber manufacturing the effect is permanent.
From Internet
14 April, 2012
