UV protection finishes

Since the most probable time for long-term solar exposure is in the summer, the most likely candidates for UV protective finishes are lightweight woven and knitted fabrics intended for producing shirts, blouses, T-shirts, swimwear, beachwear, sportswear, and the like. Indnstrial fabrics designed for awnings, canopies, tents and blinds may also benefit from a UV-protective treatment. 

The requirements for a material to be effective as a UV protection finish include efficient absorption of UV radiation at 300-320 mn, quick transformation of the high UV energy into the vibration energy in the absorber molecules and then into heat energy in the surroundings without photodegradation. Further requirements are convenient application to textile fibres and lack of added colour for the neated fibre. Some typical chemical snuctures useful for UV protection are shown in Fig. 

In most other cases combination with other finishes does not reduce the UV protection. A two-step application is necessary if the pH values of the UV protection finish bath and that of the other finishes are very different. The UV protection finish should be applied first. Problems may arise from limited bath uptake after a repellent finish or after calendering. "... 

Hatch K L, Standards for UV-protective textiles, from High Performance and Functional Finishes, an AATCC Symposium, Charlotte, NC, January 2000. 

The following sections will discuss some of the more important test methods in use for fabrics with durable press, flame-retardant, soil release, repellent, UV protective, antimicrobial, anti-insect, anti-felting, hand building and weighting finishes. 

Consequently, the need for innovative, cleaner, durable, comfortable, cost-efficient, and value-added functionalized cellulosic textile products, e.g., antimicrobial, UV protection, self-cleaning, easy care, soft-handle, insect repellent, water/oll repellent, antiodor and fragrance finished, etc., are still a challenge [12,47,91, 111, 127]. 

An improvement in both antimicrobial activity and UV protection functionality of finished cotton... 

In order to obtain functional fibres and textiles to meet the special requirements for buUdtech applications, a large variety of properties can be engineered by finishing and post-treating fibres, e.g. for dirt or oil repellence, UV-protection, flame retardance, higher tensile strength or abrasion resistance. 

Suitable UV and heat protection can be achieved by the textile itself. Heat and UV protection increases with the density of the textile and with the use of bulky microfibres. Cellulose fibres and silk provide lower UV protection when compared to woollen materials or to polyester with aromatic components. Increased UV protection is obtained by the incorporation of pigments like titanium dioxide into the fibres. This absorbs and reflects UV rays and creates a sun protection factor of 50. Finishing agents are alkyl p-aminobenzoates and cinoxates which also absorb UV radiation and convert it into heat. 

A large variety of desirable properties for membranes may be provided by the fibres themselves or by their finishing and post-treatment before the production of the fabric. If these do not provide the required properties such as watertightness, dirt and oil repellence, UV protection, flame retar-dance or abrasion resistance, the fabric must be coated or laminated. Additionally an unweldable textile (e.g. PILE) may have a weldable coating applied. 

Sivakumar, A., Murugan, R., Sundaresan, K., and Periyasamy, S. (2013) UV protection and self-cleaning finish for cotton fabric using metal oxide nanoparticles. Indian J. Fibre Text. Res., 38, 285-292. 

Coatings and Surface Modifications. Probably the one application of photopolymer chemistry that has the most worldwide commercial value in terms of product sales is the use of photopolymer materials for curable coatings. Most of the wood paneling and less expensive furniture manufactured today utilize UV or electron-beam curable materials for decorative finishes (e.g. simulation of wood grain) and protective coatings. In addition, the surfaces of many commercially important materials (e.g. textile fibers and polyester films) are being modified by photopolymer processes. 

Major uses for UV curing (room temperature) include use of flat stock-fillers in particle boards and hardwood flooring, and for high-gloss (no-wax) protective coatings for floor tiles, wood finishes, and other specialty uses. 

Almost no effect Soil-release finishes Antistatics, if not softening and smoothing Finishes to improve colour fastness Finishes for protection from UV or insects Antimicrobial finishes... 

---