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| Issue date:14/10/2009 |
| ATA Journal for Asia on Textile & Apparel - Oct 2009 Issue |
| Source:Journal for Asia on Textile & Apparel |
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| Finishing chemicals are expected to manifest fast growth especially in the Asia Pacific region; drivers for growth include an increasing market for industrial and technical textiles, Ian Holme writes |
According to a report on the “World Textile Chemicals Market” published by Freedonia in December 2008, the global demand for textile chemicals was projected to increase by 2.8% per year, to reach US$19 billion by 2012. While colorants and auxiliaries were considered to remain the largest product sector, finishing chemicals were expected to exhibit faster growth especially in the Asia Pacific region, e.g. in China and India. The drivers for growth are product quality, comfort and durability in apparel, as well as in the increasing markets for industrial and technical textiles.
In the industrial and technical textiles sector there is now increasing demand for a variety of functional finishes that can boost performance, enhance protection and confer higher levels of durability.
Superhydrophobicity and self-cleaning properties, water-, oil- and stain-repellency, and flame retardancy are all performance criteria that can be enhanced by the application of chemicals and finishes, or by surface coatings.
Antistatic and antimicrobial finishes, phase-change materials (PCM) and microencapsulated finishes (e.g. mosquito-repellent finishes) also have much to offer in the technical textiles field.
Self-cleaning textiles need minimal care
Self-cleaning sunshades, flags and sails made of finished synthetic fabric are possible with BASF Mincor TX TT |
The natural self-cleaning action of the lotus leaf has stimulated a number of approaches to produce finishes with a combination of nano- and micro-roughness on the fibre surface.
BASF developed its Mincor TX TT finish based upon the application of nanoparticles with a diameter less than 100 nanometres, which are embedded in a polymer matrix on the fibre surface. Engineered especially for use on technical textile fabrics such as flags, sails, sunshades and tents this durable nanostructured finish from BASF has received the Institute of Textile and Process Engineering (Denkendorf, Germany) seal of quality “Self-cleaning inspired by nature”. This quality seal is only awarded to textile products proven to have a genuine self-cleaning action based upon nanostructured surfaces like its model in nature.
The patented NanoSphere finishing technology, reformulated by research teams from Schoeller Technologies AG and Clariant International Ltd using C6 fluorocarbon technology, avoids the pitfalls of the possibility of giving rise to perfluorooctane sulphonate (PFOS) or perfluorooctanoic acid (PFOA), which can be present from C8 fluorocarbon technology. Nanosphere self-cleaning technology can be utilised to make cotton and natural fibre blend fabrics that will repel dirt, water and oils.
Finished textiles resist flame and bacteria
Finishing with BASF Mincor TX TT has been applied on polyester awning fabrics
NanoSphere self-cleaning technology can be utilised to repel dirt, water and oils | |
A new non-halogenated flame retardant, Cetaflam BC8380, was developed by Avocet Dye & Chemical Co. Ltd, Brighouse, UK. Cetaflam BC8380 developed to provide a non-halogenated flame retardant treatment can be back coated on to polyester automotive fabrics. It can be applied in combination with a polyurethane, acrylic, or SBR (styrene butadiene resin) binder / resin system and a major advantage is that the product requires only low application levels. Typically application levels in the 30-60 gsm range are required dependent upon the construction and weight of the polyester fabric.
When liquid is spotted on the coated side of a flame retardant-coated polyester automotive fabric and the material is subsequently dried some products can migrate to the fabric surface by leaching, giving rise to the production of a white ring. A major advantage of Cetaflam BC8380 is that this leaching effect is greatly minimised and, in the majority of cases, a white ring does not develop. This leaching problem has been overcome by careful component selection and blending of the Cetaflam BC8380.
Clariant introduced its range of Appretan E dispersions for finishing technical fabrics such as coated textiles and nonwoven fabrics. Appretan E dispersions are APEO (alkyl phenol ethylene oxide)-free and can be applied without the need for a formaldehyde-containing external crosslinker such as a melamine formaldehyde resin.
The Appretan E polymers also comply with the zero formaldehyde requirements stipulated by Japan Law 112, Oeko-Tex and the European Union Ecolabel and can be combined with flame retardants, fluorotelomers and thickeners to impart resistance to water, alcohol and solvents. Appretan E dispersions are used to enhance the technical performance of technical textiles.
The permanent flame retardant finishing of cotton and cotton-rich blends can be achieved using Pekoflam DPN.CN liq conc from Clariant. This flame retardant system can provide excellent fastness to washing, and depending on the crosslinker system used is effective at wash temperatures up to 95°C. The product is a low yellowing flame retardant.
Sanitized AG launched its novel Sanitized Silver antimicrobial finish, which is based upon silver salt, and is not based upon nanoparticulate silver.
Sanitized Silver can be applied by the exhaust method or by padding, and does not require the use of a binder. The silver salt acts on the bacterial cell membranes preventing their growth, and thereby hindering cell reproduction. Many fabrics that are soft and stretchable cannot be treated by the exhaust process; hence the Sanitized Silver finish, which can be applied by padding, allows a wider range of fabrics to be given an antimicrobial finish.
Sanitized Silver is approved under Bluesign and Oeko-Tex Standard 100 registration (Classes I-IV). This antimicrobial finish is claimed to offer a high resistance to washing, e.g. 50 or more wash cycles at 140°F (78°C).
Many technical fabrics must retain antistatic properties within the environment of the end use, e.g. in the electronics industry. Static generation in polyester fabrics, especially in dry atmospheres, can be a problem, but Sarex (India) offers a new antistatic finish specially developed for polyester termed Fabfeel Conc. This product not only confers antistatic properties but also, because of the hydrophilic nature of Fabfeel Conc, is also claimed to promote improved levels of wearer comfort in apparel.
Maximum performance combined with a minimum environmental footprint are features of Oleophobol CP from Huntsman Textile Effects. It is based upon short chain chemistry from DuPont Chemical Solutions Enterprise and cannot break down to PFOA in the environment. DuPont Capstone for textile finishes are the chemical basis for Oleophobol CP. It also complies with Oeko-Tex standard 100 and is a Bluesign-approved finish.
Specially treated sailcloth repel water
Adding water repellency to textiles is another popular area of special finishes used on industrial and technical textiles.
A number of treatments can help prevent the passage of water through fabric to better repel water, to allow the fabric to last longer, to enhance tear strength of the fabric, and to achieve better weathering properties.
Ravlex provides benefits mentioned above, according to a US-based finishes and coatings supplier, Whitford Corporation.
The waterborne system (Ravlex 60-620 and Ravlex 60-420) is applicable for sailcloth and tents. The Ravlex 60-620/60-420 system is waterborne; capable of achieving in excess of two-meter hydrostatic head; and suitable for cotton, polyester, polyamide fabrics. It can also be used for breathable textiles.
Varied finishes are used for two ranges of substrates. Low-temperature materials include polyester, polyamide and polyurethane, whereas Kevlar, Nomex and fibreglass are high-temperature materials.
All in all, a number of functionality can be attained with the use of special textile finishes/coatings, including low friction; high resistance to abrasion; water repellency; combination of tensile strength and flexibility; and resistance to oils.
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Copyright © Adsale Publishing Limited. Credit goes to Adsale Industry Portal when used.
We reserve the right to take legal action against any party who reprint any part of this article without acknowledgement. For enquiries, please contact the Editorial Department. |
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