DIGITEX
exploring the benefits of digital finishing of textiles
Resources
Opportunities
Social
The technology facilitates a customised approach to the design of work wear for specific users and contexts of use and offers the following benefits:
- Reduction in the use of chemicals to achieve basic protection. Protection, against cold, heat, wind and water, is a basic function of textiles. And by using fine patterning of droplets (controlled deposition), barrier properties can be achieved with lower use of chemicals creating lighter more wearable protective garments
- Enhanced protection in high-risk environments. Workers within particular environments require protection against specific threats. For example pharmaceutical or medical workers may require protection from chemicals (gas, fluids and dust) or biological agents (bacteria). Such protection can be achieved by non-organic finishes (TiO2, Silver) or organic compounds (Chitosan, Chipro’s) but the costs can be prohibitive. These expensive and delicate compounds may be effectively and economically applied by using digital finishing processes that enable reductions in amount of chemical used, and easy application and fixing at room temperatures
- Advanced warning of risk-escalation in low-risk environments. Chromic sensors (materials that change colour on exposure to environmental stimuli) can react to the presence of hazardous substances including biological and chemical agents. Electronic systems exist for this purpose but digital finishing enables such protective performance to be integrated into work wear.
- Localise functionalities. Workers’ bodies in hazardous environments are not evenly exposed to risk. For example, a worker’s routine may involve carrying a load supported by their forearms against their chest. If the load has an impact when in contact with the skin then this means that the forearms and chest may require greater protection than the rest of the body. Digitally programmed micro-deposition allows control of where the amount of protective treatment is applied on a textile or garment. This allows for both scaling protective levels (more or less protective finish applied) to the specific requirements of the body position (more protective material applied to chest and forearms). In this way DIGITAL FINISHING enables a better use of materials, avoids overprotection and enables product design strategies that enable less labour intensive sewing (‘print’ rather than ‘patch’ or ‘seam’ protective areas)
- Improved skin protection. Occupational skin diseases (eg eczemas) result in the loss of 3 million working days each year and are often directly related to exposure to chemicals in the workplace. These skin diseases are often highly localised to the lower arm and neck and therefore localised finishes with controlled release properties can add comfort and reduce the impact of water, infectants and chemicals on the skin, so reducing health and economic impact
- Scale functionalities to specific user requirements. Risk exposure differs according to occupation, gender and age. Statistically, women suffer more exposure to skin diseases. Those aged 55 years and over suffer the greatest incidence of long development-time occupational illnesses, such as cancers and cardiovascular diseases, highlighting the dangers of long lasting exposure to risks and problems in traceability of exposure. Digital micro-disposal of functionalities allows for both more precise ‘dosing’ of protective functions and detection of exposure to risks
- Improve comfort and increase acceptance of protective wear; To give protection, protective work wear must be worn. Acceptance of professional protective equipment is essential and sometimes critical (e.g.). To gain this acceptance and use, often requires a better balance between comfort and safety within the design of the garment particularly in SMEs and amongst self-employed people and temporary workers were protective clothing education and training is typically less. DIGITAL FINISHING enables a wide range of protective functionalities without restricting the performance of the wearers – more discrete finishing enables lighter garments offering increased comfort that leads to greater acceptance/use
- Monitor the integrity of functionalities and exposure to dangerous substances; Self-monitoring textiles (through a combination of sensors and memory devices) can register the exposure of workers to risks, trace the moment of exposure and assist in improving working environments. Self-monitoring textiles can track the levels of protection offered by a substrate. By combining tracer functionality with other desired functionalities e.g. flame retardency, the wearer can observe the level of protection that their garment offers. Overt charcteristics communicate the presence of covert characteristics that may be affected by exposure to damage, abrasion and wearing out. This enables improved monitoring of conformity to required standards e.g. levels of flame retardency.
These characteristics can contribute to achievement of health and safety policies at work (Art. 137 of the EU Treaty) and personal protective equipment as well as exposure of workers to physical agents (Council Directives 89/655 656 and 686, 80/1107/EEC and Commission Directive 88/35) - important drivers for work wear development.
Environmental
Digital finishing is able to apply required functionalities (such as protective performance) whilst minimising use of resources (water, energy, chemicals) and has the potential of setting new standards in sustainable production and reducing environmental contamination linked to textile finishing. Its benefits in this area are:
- significant reductions in water and chemical use and associated chemical and water waste. Yearly, 120 Mtons water and 40 Mtons chemicals are processed in textile finishing, 90% of which needs to be treated at the end of the pipe before returning to the environment or production cycle. The release of chemicals in the water is a huge problem for the quality of life and health of European citizens.
- it contributes to the EU’s environmental policy. Digital processes allow for improved monitoring of chemicals used in the finishing process. This enables a better traceability of used chemicals in the framework of the REACH (Registration, Evaluation and Authorisation of Chemicals in Europe) process.
Economic
- digital finishing protects and develops high skilled employment within the EU by increasing the global competitiveness of the EU textile sector, creating unique value via a knowledge intensive (rather than labour intensive) process that is responsive to consumer needs.
- digital finishing contributes to three objectives defined by the EU Commission’s Textile Technology Platform:
- 1. Realisation of added value functionalities offering better performance for the user – in particular in technical textiles
- 2. Realisation of mass customization and hence taking benefit of nearness to the consumer and
- 3. Taking costs out of the production cycle by integrating processes and hence shortening response time to the market.
The Challenge
Digital finishing has the potential to make a positive impact on (I) the textile and clothing industry, (II) the users of work wear (or other performance apparel) and, (III) on the environment.
- I. In Europe, 9 million workers operate in harsh environments, subject to hazards of high temperature and chemical or biological exposure. Since employers must supply protective clothes to their employees, the work wear sector offers great potential for development of products utilizing digital finishing. This technological advantage confers greater competitiveness to the EU textile and clothing sector, particularly on short fabric runs (30-600 meters) and smaller garment batches. Mass-customization of garments linked to specific user needs and contexts of use (such as exposure to risk) also benefit from proximity to the customer (within the EU). Whilst the work wear clearly exploits these advantages, product innovation is not limited to work wear. There is potential for exploitation of digital finishing in the creation of any product where augmented functionality is required that can be applied by localized and multiple depositions of chemicals upon textile.
- II. Users of work wear have the benefit of protection levels better suited for the specific risks and a better balance between protection and comfort and therefore a positive impact on performance and productivity. The wearer may benefit from better work conditions, better comfort and work satisfaction, reduction in illness and lower exposure to chronic diseases.
- III. Environmental impact linked to substantial savings in water (50% - 70%), energy (40% - 60%) and waste (20% - 50%) associated with textile finishing in the EU can lead to reductions of 8 to 12 Mtons/year of water corresponding with economic savings of about 10 to 15 M€/year[1].
Digital finishing enables the creation of a new generation of highly functional textiles better able to match the specific demands of users.
For designers and manufacturers, digital finishing strengthens the ability to serve specific users with specific functionalities.
For textile producers and garment manufacturers it creates the opportunity to be more competitive in small volumes, to speed up response times and to reduce stocks by shifting to a "functionalisation on demand" concept. Further advantages include cost advantages in making up (up to 10% savings on material and labour costs) as functionalities are applied to a single substrate (fabric) avoiding the need for paneling of fabrics of differing performance characteristics to achieve multiple and localized functionalities (less patterning, losses in cutting and taping) within the final garment. Moreover, shorter lead times will lead to lower stock levels and a saving in working capital.
The challenge for designers is to identify those users and contexts of use that require apparel or other products that uniquely exploit the characteristics of digital finishing namely:
- locatable functionalities/performance characteristics
- multiple functionalities/performance characteristics
- customisation of garments bespoke to user requirements (gender, size, body shape, therapeutic requirements, scenario of use/risk)
- reduced seaming in construction of garments
There are four functionalities that can be applied to textiles using digital finishing at this time:
- Chromic Functionality
- Controlled/Slow Release Functionality
- Single sided hydrophobic/hydrophilic Functionality
- Anti Static/ Anti Bacterial Functionality
Chromic materials
DIGITEX makes it possible to make localized patterns of functionalities and therefore opens the possibility of localized sensors placed on strategic positions. Herriot Watt University have developed localized functionalities that react to physical or chemical stimuli and are therefore able to sense the environment and respond to their surroundings.
- Thermo-chromic functionality makes textile (or more precisely the dye applied to the textile) change colour in response to temperature change.
- Iono-chromic functionality makes textile (or more precisely the dye applied to the textile) change colour when exposed to acidic or alkaline conditions.
- Photo-chromic functionality makes textile (or more precisely the dye applied to the textile) acquire a colour (from colourless) when exposed to UV (ultraviolet) radiation, for example in sunlight, and revert to the original colourless state when the light source is removed.
Controlled release functionalities
Localized patterning of functionalities makes it possible to strategically place functionalities (or functional chemicals) on specific places on the fabric and in the cloth. In this case University of Twente have developed a controlled release system that under certain stimuli releases a functional chemical; this chemical can have a whole variety of properties depending on the product requirements and the environment the fabric is exposed to. For example a fabric may release drugs, perfumes or oils in response to stimuli such as change in acidity or alkaline or temperature.
Single sided Hydrophobic/Hydrophilic fabrics
The concept of the single sided hydrophobic (SSH) fabric is along the lines of Sympatex membrane. The Sympatex membrane consists of synthetic material that is water repellent on one side and water absorbing on the other. The membrane therefore repels water away on its outer surface while taking up sweat and moisture generated from the body from the inner side. Similarly, Single sided hydrophobic fabrics show hydrophilicity (water attracting) on one side and hydrophobicity (water repellent) on the other. This gives water repellence properties with increase comfort due to the breathability of the fabric. There are however many differences in the concept of SSH in comparison to Sympatex membrane. Firstly, we achieve this functionality with ink jet printing process where it is possible to have one-sided functionality on various substrates such as cotton and wool. Secondly, having a cotton fabric with this functionality means applications in day to day fabrics and not just on performance clothing.
Anti Static/Anti bacterial materials
Department of Fibre Physics and Textile Metrology, Poland have developed anti static/anti bacterial fabrics based on the use of bi-functional inks that include poly pyrole and carbo nano tubes. Thes bi-functional inks can be ink jet printed onto textiles and can be located where required. This means that only those areas of a garment or product that require anti static/anti bacterial functionality receive these performance characteristics.
[1] These initial calculations by Ten Cate - which have been used in a national programme named "Subsidie Regeling Milieu Gerichte Technologie" in 2003 (ProMT2003) and have been approved by the national agency Senter Novem in the Netherlands – show a reduction in water use of 50% - 70%, in energy use of 40% - 60% and in waste of 20% to 50%, depending on process parameters.