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Ultraviolet Protection of Knitwear Fabric

Ultraviolet Protection of Knitwear Fabric. Polly Chiu, Jimmy Lam Institute of Textiles & Clothing The Hong Kong Polytechnic University. Outlines. Introduction and Background Experimental Details Six Reactive Dyes Group Comparsion of different shade Laundering UV transmission test

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Ultraviolet Protection of Knitwear Fabric

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  1. Ultraviolet Protection of Knitwear Fabric Polly Chiu, Jimmy Lam Institute of Textiles & Clothing The Hong Kong Polytechnic University

  2. Outlines • Introduction and Background • Experimental Details • Six Reactive Dyes Group • Comparsion of different shade • Laundering • UV transmission test • Results and Discussions • Effect of Colour • Effect of Shade • Conclusions The 10th Asian Textile Conference, Sept 7-9 2009 Ueda, Japan

  3. Introduction & Backgrounds • Growing consumer demand for increased sun protection has driven the sun care market into innovative areas, including UV protective clothing. • Such growth highlights the importance for consumers of protective aspects of clothing as opposed to fashion or utilitarian functions. • UV protective clothing offers more durable protection against the harmful effects of the sun’s ray than sun screen. The 10th Asian Textile Conference, Sept 7-9 2009 Ueda, Japan

  4. Introduction & Backgrounds(2) • It is believed that the dominant reason for the occurrence of skin cancers is related to cumulative UVR exposure. • Australia has the highest incidence of skin cancers in the world because Australia experiences some of the highest levels of solar ultraviolet radiation in the world. • The reasons for the high levels of UVR include its geographical location, its close proximity to the equator, relatively clear atmospheric conditions, and most importantly, the influence of ozone depletion. The 10th Asian Textile Conference, Sept 7-9 2009 Ueda, Japan

  5. Introduction & Backgrounds (3) • The most common human cancer is thought to be the basal cell carcinoma (BCC), but it is arguable due to the well-recognized problem of under-registration of skin cancer. • The incidence of MM is almost 100 times more common in Australia, and is approximately 30 times more common in the UK and US comparing to HK. • In Australia, over one thousand people died from skin cancer annually and there are approximately 270,000 new cases of skin cancer diagnosed per year. • While in Hong Kong, non-melanomaous skin cancer became one of the top 10 cancers in Hong Kong for the first time in 2002, and then it ranked as the 9th most common cancer in Hong Kong in 2006; The 10th Asian Textile Conference, Sept 7-9 2009 Ueda, Japan

  6. Table 1: epidemiology of melanomas in different countries in 2003 The 10th Asian Textile Conference, Sept 7-9 2009 Ueda, Japan

  7. Introduction and background • The increasing incidence of skin cancers world-wide and the misconception of sun protection methods by the general public led to this research about how to provide UV protection by clothing, using chemical and textile engineering approach. • It is believed that clothing, as a basic necessity, will be able to provide good solar UVR protection to human if the textile scientist chooses the correct parameters in engineering UV protective clothing. • In this research, chemical approach of wet treatment has studied and their effect on blocking those harmful UV radiations on light-weight single jersey plain knitted fabric for summer outerwear were investigated. • Initial findings showed that different dyestuffs, dye concentration and colour play an important role for UV protection on this knitted fabric The 10th Asian Textile Conference, Sept 7-9 2009 Ueda, Japan

  8. Experimental Details

  9. Experimental Details • Chemical approach was the first method to block the harmful UV radiation to our skin. Dyeing was believed to be able to modify the proportion of UV light transmitted through fabrics and could increase UV protection performance. Dyes of different colors and color depths are important because of the following : • 1) Fabrics with darker colors transmit less UV light than lighter colors; • 2) Fabrics with darker shades of the same hue have higher UV protection ability. The 10th Asian Textile Conference, Sept 7-9 2009 Ueda, Japan

  10. Six Reactive Dyes Group • In this study, six reactive dyes of different colors and shades were used. They contained different chemical groups as follows: • Reactive dyes: • a) Remazol Brilliant Blue BB 133%; • b) Remazol Navy RGB ; • c) Remazol Red RB 133%; • d) Levafix Blue CA; • e) Levafix Royal Blue E-FR; • f) Levafix Navy CA. The 10th Asian Textile Conference, Sept 7-9 2009 Ueda, Japan

  11. 2.Alkaline addition Salt Auxiliaries 1.Alkaline addition 60℃ Dyestuff 10’ 20-40’ 30’ 1℃/min 25-30℃ 10’ 20’ 10’ 10-20’ 10’ Figure 1: Dye curve for Remazol Dye Group The 10th Asian Textile Conference, Sept 7-9 2009 Ueda, Japan

  12. Dyes shades and laundering • Color appearance in terms of Hue was measured according to Hunter94 Model by the Macbeth CE-7000A spectrophotometer. Different shades were identified and compared later with results of UV test. • Laundering is believed to cause changes in physical properties of fabrics and hence affecting UV blocking performance. Shrinkage of fabrics occurs after laundering which cotton fibers swell and close the small gaps between neighboring fibers, hence less UV light are able to pass through the fabric. •  In this study, steaming, a quick method to stimulate laundering was used by steaming with steam iron. The 10th Asian Textile Conference, Sept 7-9 2009 Ueda, Japan

  13. UV transmission test The 10th Asian Textile Conference, Sept 7-9 2009 Ueda, Japan

  14. Results and Discussions

  15. Results and DiscussionsEffect of Dyeing • Exhaust dyeing with reactive dyes of different chemical structures was applied to the 100% cotton knitted fabric. The dyes used included: • VS type – Remazol Brilliant Blue BB 133%; • VS-VS type – Levafix Royal Blue E-FR and Remazol Navy RGB; • MFT-VS type – Levafix Blue CA; • MCT-VS type – Remazol Red RB 133%; and • TFP-VS type – Levafix Navy CA • Fabrics were dyed in 5% concentration so a very dark shade was obtained. The dyes provided different shades of blue except one for a red color. Therefore, fabrics with different color shades and color were taken to the UV spectrophotometer where the mean UPF values were measured as shown in Table 2. The 10th Asian Textile Conference, Sept 7-9 2009 Ueda, Japan

  16. Table 2: Results of dyeing on fabric UPF The 10th Asian Textile Conference, Sept 7-9 2009 Ueda, Japan

  17. Effect of Dyeing • As shown in Table 2, the control sample has a low UV protection and the mean UPF was 3.376, which could not be rated according to the Australia/New Zealand standard AS/NZS4399:1996. However, after treating this fabric by dyeing with reactive dyes,most of the fabrics showed a mean UPF of almost 1000. • The reason for the effective UV protection by applying the dyes was that the colored dyes were able to absorb UV radiation in the part of dyes absorption spectrum which overlaps with the UV spectral region. Different chemical structure of the dyes led to various selective absorption of visible light or color, therefore different proportion of UV wavelengths were absorbed by the dye which decreased transmittance and increased UV protection. The 10th Asian Textile Conference, Sept 7-9 2009 Ueda, Japan

  18. Effect of Dyeing • Increased concentration of dye of same color on same fabric led to darker shade of fabric, which also increased the UPF. • It is because more dyes were presented to absorb UV lights and thus lower transmission was achieved. • In this experiment, 5% concentration was used and was a relatively high concentration that leads to the excellent protection from UV radiation. The 10th Asian Textile Conference, Sept 7-9 2009 Ueda, Japan

  19. Figure 1: Effect of dyes on % transmission Control sample The 10th Asian Textile Conference, Sept 7-9 2009 Ueda, Japan

  20. Effect of Shade • Hue is defined as the attribute of a visual sensation according to which an area appears to be similar to one, or to proportions of two, of the perceived colors red, yellow, green and blue. Hue was measured according to Hunter94 Model and the 5 shades of blue were resulted in small difference. • This led to similar results in the mean UPF, except for Levafix Royal Blue E-FR, which may cause by experimental error (as shown in Table 2). The red dye also showed similar UV protection capability since the hue number of red was similar to those of blue. • Different color depths affect absorption and also the reflectivity of UV photons with dye molecules having a specific role. Thus it is believed that darker colors, such as dark navy blue and red used in this experiment, transmit less UV than lighter colors, such as oatmeal and white. The 10th Asian Textile Conference, Sept 7-9 2009 Ueda, Japan

  21. As shown in Figure 1, the control sample (B) showed a large UV transmission before dyeing (red colour with 0.8% transmission) with mean UPF of 3.37. • The effect of dyeing significantly reduced the percentage of UV transmission. The curve A (Leavafix Royal Blue E) reduced the UV transmission to 0.6% with mean UPF to 219. • All the other dyes (Curve J, E, C) significantly reduced the UV transmission to 0.2% with mean UPF of 998. The 10th Asian Textile Conference, Sept 7-9 2009 Ueda, Japan

  22. Conclusions • Textile dyeing and finishing process has a significant effect on reducing the harmful UV radiation on textile fabrics. This experiment shows that the open space structure of single jersey plain knitted cotton fabric (gauge 20) can be enhanced on UV protection by simple dyeing process. • The mean UPF has been increased from undyed grey fabric of 3.37 to dyed Royal Blue fabric of 219 and to dyed Levafix Nacy CA fabric of 977. • The dark colours like dark blue and red with higher concentration will result in greater UV protection of the fabric. The 10th Asian Textile Conference, Sept 7-9 2009 Ueda, Japan

  23. Conclusions • However, it is also suggested that color or color depth should be considered in combination with various properties known to modify UV transmission. • For instance, during the process of dyeing, the increased UV protection may not only cause by the effect of dye, but may also due to the effect of shrinkage after wetting which caused a tighter and closer structure. • Therefore, other properties like fabric structure, thickness, weight and tighter factor will be further investigated The 10th Asian Textile Conference, Sept 7-9 2009 Ueda, Japan

  24. Acknowledgement • The authors would like to acknowledge the funding supports from the Central Research Grant (A-AS21) from the Hong Kong Polytechnic University. The 10th Asian Textile Conference, Sept 7-9 2009 Ueda, Japan

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