The Multiple Laser Surface Enhancement (MLSE) process has the potential to revolutionise the textile processing industry globally.
MLSE produces technically superior products and significantly reduces the environmental impact of materials processing in a sector that traditionally uses high levels of water, energy and chemicals.
Expert analysis of the unique MLSE process suggests the following reductions can be achieved:
- Greenhouse gas reduction over baseline of 90%
- resource (chemical) use reduced by 95%
- water consumption reduced by 75% to 100%
- energy consumption reduced by 90%.
MLSE is a dry process, carried out at atmospheric pressures using safe, inert gases (nitrogen, oxygen, argon and carbon dioxide). The combination of plasma and photonic energy creates material synthesis in the surface of a substrate. The MLSE process can be used for material cleaning and performance enhancements, including low-temperature dyeing, water-proofing, and fire retardant and antimicrobial treatments.
The process, which operates at up to 20 metres a minute, has been fully patented and licensed. The technology can be integrated into an existing process line as a ‘modular’ unit, operating at the speed of the existing process, using the same materials handling system, or as an additional, stand-alone system.
MLSE is an example of technology transfer between industries which has facilitated a leading-edge development in both the processing and the performance of textiles. The use of photonics and plasma in a controlled vacuum environment of gases and sol-gels has long been established, particularly for the production of electronic components and metallic and non-textile polymeric substrates. The unique feature of MLSE technology is the combination of energy sources in a controlled atmospheric environment in the presence of a material substrate. The net result is conversion and material synthesis in, or optionally on, the surface of the substrate.
MLSE technology works through the creation of a high-frequency (RF) plasma in an envelope between rotating and driven rollers that extend across the width of the processing chamber.
A gas delivery system combines gases into a single feed that populates the plasma chamber;
A high-power ultraviolet (UV) laser is shaped into a rectangular cross-section providing a consistent power density over its entire length of more than 2 metres. Sophisticated optics defract the laser beam into the plasma zone.
Various applications result from changing the power intensity and pulse profiles of the laser and the plasma, and varying the mix of gases.
To date, the textile industry has embraced several technological advances that have produced various level of the performance enhancements described above.
Existing treatments involve coating systems,including spray, lick roller and vacuum physical vapour deposition processes, where a film is laid onto the textile to impart the necessary technical characteristics. Most waterproofing and stain resistance has been achieved with Teflon-based finishes, using heat to set the finished treatment. As this process is a coating, the cleaning of finished fabric causes degradation and ultimately the elimination of the required property.
Previous fire retardancy and antimicrobial treatments are complex and costly and again rely on multistage wet and heated processes treatments.
RESEARCH & DEVELOPMENT
Substantial academic and industry development work has taken place utilising plasma, with the best results being achieved using vacuum-based plasma systems for batch processing.
Some success has also been reported from Porton Down, the UK Ministry of Defence Development Centre, where plasma and fluorocarbon materials have been utilised to impart waterproofing treatments to a variety of fabrics. However, the process has not been adopted appreciably by the industry.
UV lasers have been used by some researchers to investigate their effect on surface structure and functionality, but much has remained at the ‘laboratory bench’ level of curiosity. Other developments have included the use of infrared lasers for textile cutting and textile marking and UV systems for cleaning water and effluent, primarily for cleaning sheet materials in paper, polymeric materials and metals.