Ultraviolet Protection

ByTextileS

PRESENTED BY-RAGHAV MEHRAM.TECH.(2nd Sem)

Introduction Light is very essential on earth. Source of light on earth is SUN

U.V Radiations Ultraviolet

Radiations are electromagnetic rays with a wavelength between 100-400nm.

Solar UVR that reaches earth have wavelength between 290-400nm.

Classification Of U.V Rays U.V rays has three regions depending

upon wavelength:

Ultraviolet region – A (UVA) Ultraviolet region – B (UVB) Ultraviolet region – C (UVC)

Characteristics Of U.V regions

Region Wavelength(nm)

Relative Intensity(%)

Av. Photon Energy(kj/mol)

UV-A 315-400 3.2 315

UV-B 280-315 2.4 350

UV-C 100-280 0.5 400

Factors Affecting Solar U.V Level

Sun angle Geographical Position Seasonal Effects Clouds Ozone Scattering Altitude Time of day

Effects Of U.V radiations: Human Skin The major effects

of UV are sunburn, erythema(skin reddening), skin cancer, DNA damage.

Protection Factor Protection factor is used to quantify the

protective effect of material. SPF/UPF is the ratio of actual potential

erythemal effect to the erythemal effect transmitted through the fabric.

Larger the UPF/SPF, the more protective the fabric to UV radiation.

whereSλ is Solar spectral irradiance in Wm-2nm-1 Eλ is relative erythemal spectral effectivenessT λ is spectral transmission of object∆ λ is band width in nm λ is wavelength in nmED is effective dose of UVR for unprotected skinEDM is the effective dose of UVR for protected skin

Factors

UPF depends upon following factors: Cover Factor THE MORE THE COVER FACTOR, HIGH IS UPF

Color Humidity THE UPF INCREASED AS THE RELATIVE HUMIDITY INCREASED, BUT THIS INCREASE IS FIBRE DEPENDENT, MORE PRONOUNCED IN IN VISCOSE & SILK

Measuring Methods Of UPF

Measuring methods of UPF are:

UV Standard 801

AS/NZS 4396/1996

EN 13578-1

BRIEFING:

Effect Of UVR On Textile Material: U.V radiations cause degradation of

textile materials due to excitations in some parts of the polymer molecule.

This results decrease in elasticity, tensile strength.

For example:

Fabric % Loss In Tensile Strength

Nylon 100

Cotton 34

When solar radiations impinge on a textile , the radiation can be completely reflected, dispersed & absorbed

There are two possibilities of reducing UV transmittance by fabrics• To optimize the fabric construction so as to increase the skin cover

by fibers, which can be achieved by spacing the yarns as closely as possible. UV transmittance can also be reduced by improving the absorption & reflection properties

• By use of UV absorbers

U.V Absorbers

UV absorbers are colorless compounds with very strong absorption in the UV range of 290-400nm.

UV Absorbers incorporated into fibres convert electronic excitation energy into thermal energy.

They function as radical scavengers and oxygen scavengers.

Requirements of UV Absorbers:

Highest absorbency in the ultraviolet region {290-340nm} and no absorbency in the visible region.

UV Absorbers should be non-toxic and non-skin irritant.

These should be heat stable and compatible with other additives in finish formulation.

It should remain stable against UVR itself. It should be suitable for use in powder, liquid

detergents and rinse conditioners.

Types of UV Absorbers:

UV Absorbers are of two types: Organic Absorbers Inorganic Absorbers. Organic Absorbers: These are derivatives of O-hydroxy

benzophenone, O-hydroxyphenyl benzotriazole and O-hydroxy phenyltriazine.

These are applied by normal padding, coating, pad thermosol process.

These have excellent sublimation fastness and self dispersing formulation.

In these, orthohydroxy group is for absorption and to make soluble alkaline solution.

Inorganic Absorbers: These are compounds of Titanium oxide and

ceramic materials. These have an absorption capacity in the UV

region of 290-400nm.

Mechanism of UV Absorbers

UV absorption causes the electron density to move from the phenolic oxygen to the nitrogen atom.

The nitrogen becomes more alkaline than the oxygen as a result and a proton transfer occurs.

This mesomeric form represents an excited state, which stabilizes as a result of a radiation less transition to the ground state.

Technology:

UV Absorbers are incorporated either into spinning dope prior to fibre extrusion or in dyeing.

These are applied by normal padding, exhaust, pad dry cure and pad thermosol methods.

These are applied between 30-40g/lt. The concentration depends on type of

fibre and its construction.

COMMERCIALLY AVAILABLE UV ABSORBERS

• RAYOSAN PRODUCTS INCLUDES RAYOSAN C PASTE, RAYOSAN CO LIQ. & RAYOSAN P LIQ.

• RAYOSAN C & RAYOSAN CO LIQ. ARE DESIGNED FOR CELLULOSIC, POLY AMIDE & WOOL FIBRES. THEY BIND WITH FIBRE IN THE SAME WAY AS A REACTIVE DYE

TEMPERATURE RANGE-70-95◦ CTHESE PRODUCTS ABSORB MAINLY IN THE UV B REGION. THE ABSORBING EFFECT DEPENDS UPON THE VOLUME APPLIED

RAYOSAN P LIQIS DESIGNED FOR FINISHING PET & ACETATE FIBRES & CAN BE APPLIED TOGETHER WITH THE DISPERSE DYES.IT HAS HIGH ABSORPTION IN THE TOTAL UV REGION

UV ABORBERS BY CIBA

• TINO FAST CEL(BI-REACTIVE OXALIC ACID DI-ANILIDE DERIVATIVE)

• THE DEGREE OF EXHAUTION & FIXATION IS EXCELLENT• COMPATIBLE WITH CIBACRON LS & CIBACRONE FN DYES• REQUIRES VERY LESS AMOUNT OF SALT TO MAXIMISE BATH EXHAUTION• HIGH AMOUNTS MAY LEAD TO SHADE VARIATIONS

TINO FAST PES• DESIGNED FOR PET & ACETATE• IT IS REQUIRED IN VERY LESS AMOUNT AS PET ITSELF CONTAINS

DELUSTERANTZ(TIO2), WHICH ITSELF IS A UV ABSORBER

THANK YOU