Final Report Summary - NANOBOND (Integration of emerging soft nanotechnology into the functionalisation of textiles)
The idea of the NANOBOND Project comprised the development of a system consisting of:
(i) the chemical activation of the fibre surface with a polymeric nano-coating for durable binding of functional molecules;
(ii) the effective incorporation of a selected functional finish for permanent modification of the textile properties, in the first instance a non-leaching antimicrobial agent;
(iii) the development of a universal technology applicable at any type of textiles and non fibrous materials.
The practical starting point of the NANOBOND project (see http://www.nanobond.org/ online) has been the existing surface activating polymer and non-leaching, antimicrobial coating technology developed by Devan and DPPT. The project aimed at the development of a sustainable surface activation technology based on the self-assembly power of a 'soft nano-technology' for the development of versatile, highly functional textile products adapted to the needs of consumers. The main emphasis has been on the development of inherently antimicrobial and multifunctional textiles due to the advance of nosocomial diseases in Europe. As alternative to commonly-used biocidal chemicals that are deliberately released from articles or surfaces and that are potentially environmentally harmful, we developed a new surface modification concept to control surface microbial contamination, particularly the development of bacterial colonies and biofilms.
New surface activating polymers based on the reaction of amines with epichlorohydrin have been developed. For this purpose, a low molecular weight azetidinium compound has been developed that contains a new bi-functional coupler and that can be added to various amine containing polymers. By this approach azetidinium functional groups are attached to the polymer backbone in a more quantitative and controlled way. In addition, further hydrophilic groups are introduced in the polymer backbone, which increases the hydrophilic / hydrophobic ratio of the polymer. It was found that the newly developed polymers are easily dispersed in water, while the surface affinity is retained. This is an improvement with respect to previously known surface activating polymers which are more difficult to be dispersed in water. Water solubility is an important aspect for textile finishing as textile treatment from solvents requires special facilities and is barely economically feasible in Europe. The evaluation of the developed polymers with regard to their applicability into the industrial process has been proofed. Thus, upscaling has been performed and the newly developed polymers have been applied onto textiles by the small and medium-sized enterprises (SMEs). First innovative textile products with improved antimicrobial activity have been developed by the SMEs.
Further approaches to develop multifunctional textiles included the development of flame retardant polymers and the integration of carrier systems, in particular microcapsules which contain active agents (here: antimicrobial agents, fragrances and phase change materials). The potential of the developed flame retardant polymers with regard to their effectiveness was demonstrated. Pre-treatment with surface activating polymers was found to improve uptake and fixation of microcapsules on textiles.
Studies on the influence of the structure and conformation of the newly developed polymers on their antimicrobial activity were performed with respect to their membrane affinity using different phospholipid Langmuir monolayer models and their inhibition potential against proliferation of E. coli, B. subtilis and S. aureus. The studies with the model membranes led to the result that micro-structural / conformational differences play a role in the interactions of polymers with the lipid layer. Furthermore, a structure-property relationship was established by analysing the antimicrobial activity of the polymers against E. coli, B. subtilis and S. aureus as function of the length of the alkyl chains at constant ratio of alkyl to cationic groups.
The final result of the project is the development of a universal, sustainable surface activation technology based on soft nano-coatings derived from specialised polymers that can themselves either create functionalised surfaces, or can provide a durable template from which functional properties can be built for the development of versatile, highly functional textiles and other products adapted to the needs of consumers. The main emphasis has been on the development of inherently antimicrobial and multifunctional textiles. The background for this has been the actual need to prevent nosocomial diseases in hospitals and nursing homes etc. Considerations of the safety of users, environmental damage and cost mitigated the 'over-treatment' approach and, thus, the focus has been on the development of non-leaching permanent antimicrobial coatings applicable to different types of textiles and non fibrous materials.
The assurance of high durability of the textiles treated in the developed process leads to a reduction in performance costs.
Project context and objectives:
Whilst the traditional European textile industry has experienced increasing competition from low-cost manufacturing countries, a new prosperous technical textile industry has grown, representing high value, technological manufacturers and producers. These companies remain economically viable because of the significant inputs of technical and quality elements that are more readily absorbed by the high-end applications in which their products and processes are used. Furthermore, technical textiles constitute an enabling technology for other important industries, e.g. light weight construction, automotive and medical technology.
Yet also in this high end market, industries face a permanent pressure to remain competitive. Evidently, continuous advancement of premium products alone may be not sufficient but industries must also refocus to medium- and low-tech large volume products by developing new, highly flexible production technologies and integrating fast feedback strategies along the production line from pre- to final products to rapidly respond to market demand. Such flexible production technologies must overcome the economic dilemmas between efficient large scale production and customer oriented product diversification on one side and minimum complexity versus elaborate optimisation of production processes on the other side.
This project addressed competitiveness in fibre and textile refinement in high wage European countries by the development of a technology that comprises easy diversification, fast adaptability, efficient use of recourses, and reduced complexity. The technology has been designed to be integrated in existing production lines and it is supported by a 'pull through' business model where the benefits of the technology are demonstrated on finished products in order to create a market pull situation through the production chain. The most important area of activity has been the technical development of products and processes for reducing contamination with microbes from manufactured articles, including textiles, during use. In the first line, this is necessary for health reasons, but also for maintaining performance and function of technical textiles. Nevertheless, by prolonging the useful life of an article, significant environmental benefits accrue, from the reduction in waste and the requirement for reduced cleaning in terms of frequency and energy / water use. Thus, easy-to-clean, soil release and antimicrobial properties are linked aspects that are of great importance affecting comfort and freshness in consumer apparel, reduction of spoilage or wastage during storage and transport, increase of the useful lifetime of articles, maintenance of health and avoidance of cross-contamination in medical textiles. These benefits further contribute to the overall goals of sustainable product development, and, through reducing in-built disposability, to reducing energy demands and the protection of our water resources. Another key area focuses on promoting adhesion in composite products with tailored mechanical and light weight properties.
The approach followed in this project has been based on a multifunctional bonding concept and does not rely on nano-particulates, but rather on molecular structuring at the nano-scale. It comprised the following:
- Adaptability to a wide range of consumer and industrial applications
The bonding technology can be extendible to use on any surface where performance properties may be required to maintain functionality in use. There are many similarities between textile surface properties and those of paper, leather and wood. Multi-functional performance of those substrates are also hot topics, for example, paper filters, leather for shoes and gloves, wood structures to be preserved from bad weather conditions. The developed surface activation technology can be 'spinned-off' to those related industries.
- Highly-tailored solutions by altering the characteristics of the polymeric nano-film
The NANOBOND project exploits self organisation to create nano-structured and functional surfaces that can impart multiple beneficial properties, or provide a template for anchoring further functional finishes. Examples include moisture management, fire retardancy, ultraviolet (UV).
- A responsive technology that adapts to the particular requirement for antimicrobial effect without 'swamping' the environment with the un-restrained release of antimicrobial agents, which is typical of other antimicrobial technologies
The NANOBOND technology, combined with an organo-silane antimicrobial product, creates an antimicrobial surface that functions by a physical rather than a chemical mode of action. Thus, antimicrobial performance is proportionated to specific needs, whether it is for apparel or for medical textiles or devices.
- Durability and effectiveness for the life of the goods has been clearly an important aspect in defining the sustainability credentials of the project. Articles treated with the NANOBOND / antimicrobial technology have a longer natural lifetime through protection against damage and spoilage. Thus, the initial cost of protection can be recouped through the increased longevity of treated articles.
- Low application levels during processing, to attain maximal performance and limiting the potential for release of chemical products
The permanent binding of the chemical finishes to textile surfaces further reduces the potential environmental harm because no chemical products are released to the environment during use, including laundering. The surface-bound nano-film approach to the development of performance finishes thus addresses important ecological issues.
- Easy application of the proposed technologies which will be integrated into the so-called 'wet processing' and does not require extensive modification or capital investment in expensive, sophisticated plant such as vacuum or Corona machinery
The novel technology was developed specifically to make use of the type of equipment classically employed and widely available in textile processing mills, including in SMEs, providing a drop-in technology. Thus, the time to market for these technologies, once developed, is rapid and brings a high-tech concept to a traditional industry without significant cost. This is one of the major benefits of this development. As a consequence of the technical achievements to be realised in the NANOBOND project, Devan and DPPT established a technological platform to which the other SME partners have access to develop their prototypes and to be trained in the use of the technologies. This platform is used as a pilot line to demonstrate the significant reduction in the time from laboratory studies to prototyping with an ultimate target 'less than 15 days'.
- The technology will be licensed to end-users under a process know-how technology transfer arrangement and Devan will manufacture and sell the developed chemicals. Industrial partners in the consortium will receive a free licence to use the technology in their respective field(s) of application. The licensing approach has two major advantages: good protection of the know-how and effective transfer of the technology to the user SMEs for optimum application. The licence fee will include the cost of education and training and royalties will be included in the chemical product prices.
- The focus on the differentiation between consumer groups (like sick people, older people, travelling people, sportspersons etc.) is in the responsibility of each SME in function of its respective market. Whilst, DCS and I-Care are able to focus the development of their products to the needs of individual consumers, the strategy of the other SME's is to develop differentiated products for diverse end-user groups which offers a degree of choice from a range of options. The technology allows easier integration of multi-functional properties. This means also that the SMEs differentiate their products not only from the competition but also have the ability to tailor products in function of the target consumer group.
In summary, the NANOBOND project aimed to develop a sustainable surface activation technology based on the self-assembly power of a 'soft nano-technology' for the development of versatile, highly functional textile products adapted to the needs of consumers. The main emphasis has been on the development of inherently antimicrobial and multi-functional textiles. As an alternative to commonly-used biocidal chemicals that are deliberately released from articles or surfaces and that are potentially environmentally harmful, a new surface modification concept to control surface microbial contamination, particularly the development of bacterial colonies and biofilms was proposed. This concept addresses:
(i) the adhesion of the microbial organisms to a surface;
(ii) the interruption of the biological functions that are vital for bacterial proliferation;
(iii) killing or controlling the microbial organisms that come into contact with the functional surface.
Beyond this, NANOBOND addressed also products and applications such as adhesion in composite products and non fibrous materials.
Project results:
As mentioned above, easy to clean, soil-release, soft touch and antimicrobial properties are linked aspects that are of great importance in sustainable product development, to save energy, ensure hygienic use and to protect our water resources from undesired contamination. Such properties can be obtained through surface functionalisation. Many surfaces, however, have no or only small numbers of reactive groups, thus the introduction of any functionality requires their prior activation. The typical method of surface activation is by 'physical' treatments using plasma or corona discharge, or in combination with, or as a pre-treatment for, chemical treatments. Such processes however, imply costly new equipment investment, the use of either vacuum (high energy cost) or an inert gas (cost and energy) or atmospheric costs (e.g. generation of ozone). Also, many of these treatments lead to unwanted changes in textile properties, such as an adverse change in handle or a reduction in strength.
In this field, the NANOBOND technology offers a more versatile alternative to a variety of application-specific methods for the fabrication of functional surfaces. The method applied in the project comprises the development of widely applicable covalently attached nano-coatings derived from specialised polymers that can themselves either create functionalised surfaces, or can provide a durable template from which functional properties can be built.
The basis of the research in NANOBOND focused on an a universal technology that will be applicable not only to flexible surfaces like polymers, foams, leather or paper but also to any hard surface like wood, concrete, metals, etc. Additionally, as it was planned to follow the 'drop in' technology approach, the use of processes and substances developed in the project will not require investments into sophisticated equipment from users. As the result, the time to market of products finished using new technology will be short.
One of the important surface modifications, which were studied in detail in the project, was prevention against build-up of bio-films on surfaces (antimicrobial). Consumer articles - including textiles - treated with antimicrobial agents are now widely available, and the use of antimicrobials increases the serviceability and longevity of treated articles. In addition, there are clearly potential comfort and aesthetic benefits, as well as health benefits in appropriate circumstances, for example for textile materials used in a variety of medical applications. But there are a number of key issues concerning effectiveness, human safety and environmental impact that must be addressed when considering the widespread use of such antimicrobial technologies. The maintenance of effectiveness after multiple uses and laundering is clearly a requirement of treated articles for the consumer, from the point of view of value for money and in terms of continuing to provide a performance benefit. The maintenance of effectiveness is of even more importance when considering medical textiles.
The most common approach to resolving the question of durability is to apply a high loading of the antimicrobial chemical to the treated article, by some means. During use, such compounds are leached from the article, a necessary process upon which their effectiveness relies as these compounds must be taken up or absorbed by micro-organisms. However, the compounds leached from the treated article in use - and during laundering - present unnecessary hazards. In terms of human health, the antimicrobial agent will cause destruction of harmless (indeed, beneficial) bacteria on the skin of the user. From an environmental viewpoint, uncontrolled release of antimicrobial agents into waste waters can have an adverse effect on effluent treatment plants, for example. Furthermore, release of antimicrobial chemicals in such a manner implies a finite effective life, which will vary considerably depending on the initial loading factor. In short, a more controlled and responsive technology is required, where the uncontrolled release of antimicrobial chemicals into the environment is avoided.
In the NANOBOND project, considerations of the safety of users, environmental damage and cost mitigate the 'over-treatment' approach and, thus, it was focused on the development of non-leaching permanent antimicrobial coatings applicable to different types of textiles and non fibrous materials.
The consortium possesses a non-leaching antimicrobial technology used for textiles based on the organo-silane compound commercialised as AEGIS, which formed the reference to the studies. The textiles finished with this compound show good resistance against a broad spectrum of Gram-positive and Gram-negative bacteria, as well as fungi (mould, mildew) yeasts and algae. The anti-fungal activity indirectly provides treated textiles with protection against house dust mites, an important allergic trigger for many people. Whilst sufficient for some applications, the durability of the coating needed to be increased for some applications, particularly use in medical textiles.
It has been observed, however, that the properties of AEGIS are significantly improved when the antimicrobial agent is co-applied with a surface activating polymer (Nanolink, also possessed by the consortium). The addition of such an activating polymer increases notably the durability and performance of the antimicrobial coatings to washing processes. For cotton, the antimicrobial protection using AEGIS coating begins to lose effectiveness after 20 wash cycles at 60 degrees Celsius, while the coatings additionally containing surface activating polymer show a high level of antimicrobial activity up to at least 30-40 wash cycles at 60 degrees Celsius. A similar tendency was noticed for synthetic textiles (polyester) where the introduction of surface activating polymers increased durability and activity of AEGIS coatings from 30 wash cycles at 60 degrees Celsius up to at least 50-60 cycles.
Through this project, the development of such coatings which will be stable on washing up to 100 or more washing cycles at elevated temperatures (at least 60 degrees Celsius) was planned. This should be achieved by detailed studies of the mechanisms which govern the adsorption / desorption processes of the surface activating polymer and antimicrobial agent. The assurance of such durability is very important in case of bedclothes for hospitals or hotels, surgeons' gowns and nurses' uniforms. These textiles need to be washed very often and if not sufficiently protected will lose their protective properties quickly and will be discarded which will lead to an increase in costs.
In the project, the mechanism of antimicrobial activity of the prepared coatings was to be evaluated, furthermore. In the literature, several models describe how antimicrobial polymers interact with bacterial cell walls and membranes, killing the bacteria. For instance, poly(ethylene imine) (PEI), a poly-cationic polymer, has been shown to make Gram-negative bacteria permeable to hydrophobic antibiotics and to detergents. Massive alterations in the outer membrane (OM) of PEI-treated bacteria were observed by electron microscopy of thin sections. It was also reported that the antibacterial activity of poly-cationic molecules is decreased or disappears completely upon crosslinking or upon being insolubilised. However, if the immobilised poly-cationic chains are sufficiently long and flexible to be able to penetrate the bacterial cell walls, the antibacterial properties persist. Yet, the biocidal mechanism of such polymers is still not clarified. It has been proposed that the polymer backbone acts as if it were a long alkyl chain that penetrates bacterial cell membranes. This was to be evaluated for the obtained coatings.
Ultimately, the focus of the project was to include other properties into surfaces such as moisture management, fire-resistance, easy-to-clean, UV-protection, softness etc.
Potential impact:
Strategic impact of the project
The project aimed to develop new knowledge-based technologies that address the need to enhance the technical performance of consumer articles, particularly apparel, sportswear and bedding. Further applications of the technology were to be evaluated in polymeric materials such as PU-foams for hospital or institutional applications and in textiles such as patient gowns for hospital use. Industrial (SME) partners active in the full range of these fields of application have been key participants in the project aiming at an incorporation of the developed technologies into their manufacturing processes or at the dissemination of the technology to other high-end users in selected industries. The project coordinator has been a research and development (R&D)-led company involved in developing highly-specialised chemical technologies for the textile industry. The project concept originated from the coordinating SME, which intended to develop a greater understanding of the influence of nano-coatings and to broaden their applicability. The research and technological development (RTD) partners have been chosen specifically because of their high level of sophistication in researching nano-coatings, polymers, antimicrobials and related topics. The other SME partners have been selected because of their involvement in the development of consumer products with a high technical content that allows differentiation from low-value mass-market goods. Furthermore, the outcomes of the project are applicable to medical textile products, where the need to impart specific performance such as antimicrobial behaviour is important to the quality and functionality of the goods. The other goal has been the transfer of the technology from textiles to the development of a new universal tool to finishing of non-fibrous elastic materials as well as the finishing of hard surfaces like paper, wood or leather.
The goal of the project has been the integration of new knowledge on nano- and material technologies with conventional production technologies in the traditional textile finishing sector and in textile cleaning, polymer processing and other industries.
The outcome of the project is a new concept in nano-structured polymeric coatings, which represents a novel application of 'soft nanotechnology'. These nano-structured coatings provide an activated surface for the further functionalisation of all textile goods to impart beneficial performance and health properties. The consortium has practical evidence to show that a functionalised polyether forms a coating on a textile surface that orients in such a way as to influence the surface properties of the textile fibre. It is known that there is an interaction between this polymer and an organo-silane with antimicrobial function, but the nature of that interaction is not known, and can be optimised by developing such an understanding. The organo-silane undergoes a self-polymerisation (condensation) on surfaces; it is believed that when co-applied, the structure of functionalised polyether may influence this self-polymerisation, which leads to an unexpected increase in antimicrobial performance and durability. In addition, other performance characteristics relating to comfort, health, aesthetics and sustainability may be introduced by using the nano-coating as a platform or template for further specific functionalisation. These surface modifications are considered to be 'passive' - there is no change in the basic form or function of the textile material, but the applied technology (antimicrobial, moisture management, fire resistance etc.) responds to a specific need and the localised environment in an appropriate way. The durability of the surface modifying nano-coating enables permanent performance benefits to be imparted for the life of the treated article, so increasing the useful life and sustainability of textile products. Furthermore, the bonded technology, in particular the developed coupler-modified polymers, ensure that no chemicals are released during use, reducing or eliminating the potential impact on human health and environmental safety.
The project integrated partners from a number of scientific disciplines and different end-user requirements, including those specialised in textile chemical applications, surface science, polymer synthesis, and end-users requiring specific high-tech solutions to issues relating to the microbial contamination of textile surfaces, as well as other performance requirements. The project outcomes provide commercial opportunities in a wide range of consumer-oriented goods, including apparel, sportswear and bedding, and in more specialised applications requiring a highly-tailored technical solution such as textiles for patient wear in hospitals and in foam 'comfort' pads. However, a common requirement of the SMEs is their need for high-performance technical solutions to maintain their competitiveness and innovative lead over inferior technologies from outside the EU.
The nano-coating technology requires an understanding of the surface properties of functional polymers and their interactions with other functional materials such as antimicrobials. Optimisation of the effects requires the design and manufacture of novel functional polymers encompassing the results of the early surface science studies. A key feature of the technology has been that it has been actually designed as a 'drop-in' technology. It is capable of application in conventional textile processing routes, not requiring investment in equipment or training. Thus, the technologies are capable of rapid implementation and integration into existing manufacturing processes.
The European textiles and clothing sector has suffered a drastic decline in activity in recent years, and continues to face intense competition from low-wage economies, particularly China and other Asian countries (see http://ec.europa.eu/enterprise/textile online). Nevertheless, considerable economic activity remains in the EU, concentrated on highly technical SMEs, representing a total turnover of 132 billion and a workforce of 1.83 million persons in 2011 (see http://www.euratex.org/news-and-publications/29 online). In 2011, there were about 146 000 companies within the EU-27 boundaries involved in the industry, of which 96 % are classified as SMEs (Euratex). The textile and clothing sector represents approx. 5 % of the jobs in the European manufacturing industry with an essential contribution of a female workforce (see http://www.etuf-tcl.org/index.php?s=6&rs=home&uid=689&lg=en#media online). European universities and research institutes also remain strong in the sciences and engineering related to the textile industry. For the sector to continue as a major revenue generator for the EU region, it must adapt and move towards technology- and knowledge-driven solutions in products and processes.
The market for technical textiles continues to develop and in these less price-sensitive applications the European industry is better able to compete, not only in terms of costs but, more importantly, in terms of technical ability, creativity and innovation. Within the category of technical textiles may be considered applications such as health-care, construction, geotextiles, protective clothing; in addition, with ever increasing demands by consumers for performance-enhancing clothing, we may also include sportswear, work-wear and other performance apparel in this category.
The global market for technical textiles was estimated to be worth 80 billion in 2005. A press release of Euratex aisbl from 18 June 2012 stated that the EU technical textile industry is a key development field for Europe, able to service world market(s) of more than 100 billions provided true worldwide market access is guaranteed and innovation is fostered in EU (see http://www.euratex.org/news-and-publications/29 online). The principal external markets are the United States, Switzerland and Turkey. The main producers of technical textiles within Europe are, in order, Germany, the United Kingdom, France, Belgium and Italy, the majority of which have been represented in this project.
It is clear that the strategic direction of the European textile industry must be towards developing solutions in these high added-value applications, which even so will require constant innovation to maintain a lead over the competitor regions. Companies involved in technical textiles invest a far higher proportion of turn-over in R&D (8-10 %), compared with a textile industry average (3-5 %) in order to remain competitive and such investment must increasingly be focussed on highly targeted R&D, working in close collaboration with EU universities and research centres to retain the technical lead that Europe presently enjoys over its competitors.
Societal impacts of the project
General
The industrialised textile industry has been located historically in certain regions in Europe and over the intervening period - during the last 200 years - this industrial activity was integrated into the social and cultural texture of the region and contributed strongly to its social and economical development. Certain regions became synonymous with distinct products of the textile industry, in particular through the marketing of high quality technical and fashionable products. These were important contributors to the EU balance of trade with the export of high added-value products. As the mass-production textile industry has declined in Europe, large-scale employment prospects have also diminished, but it is essential to retain significant levels of employment in the new, forward-looking niche market sectors of the industry. The importance of these high added-value niche applications has increased, and the continuation of the industry will increasingly rely on the transformation of the skills base in these traditional textile-producing regions.
The project addresses the most important Community societal objectives, as summarised below.
Employment
Technologies were developed suitable for high added-value textile applications which are more suited to production in high-wage countries in Europe. This helps to ensure the continued viability of technically advanced textile companies in high-wage countries in Europe.
Quality of life
Quality of life, health, safety and environment will be improved by reducing the negative impact of chemicals on water, air and soil pollution, and by saving natural resources such as water, whose management is of key importance for textile companies. Furthermore, the products developed will lead to less contamination of textiles with micro-bes and this will finally contribute to a reduction of nosocomial diseases in hospitals and other public institutions. Some of the developed products are foreseen for the market of the elderly aiming at an improvement of the life standard in houses for the elder and disabled people.
Knowledge-based society
The development of this new technology relies on a high level of technical knowledge and understanding of the underlying science, which has the potential to lead to further applications in non-related areas. Training and education of staff in the traditional textile industry will generate a new and highly technical workforce, better able to meet the future demands of this changing industry.
Niche markets
The project focused on technical niche markets where cost is less of a determining factor in the take-up of new technology. This is consistent with the aim of sustaining specialised industries in Europe and will be less prone to copying and substitution.
Intellectual protection
The technologies will be fully protected by patenting and licensing activities to ensure that uncontrolled dissemination of the acquired knowledge is prevented.
Dissemination and public engagement
Dissemination of the research activities and knowledge by demonstrating results on the tailored products, e.g. international conferences or in the academic teaching will help to foster dialogue with society and generate enthusiasm for science. Furthermore, the knowledge generated can be used as basis for future R&D cooperations or projects.
Economical impact for the SMEs
The basic objective has been the development of a novel bonding technology that permits the development of inherently antimicrobial and multi-functional textiles and other products where surface properties have an important role in determining performance. As an alternative to commonly-used biocidal chemicals that are deliberately released from articles or surfaces and that are potentially harmful to the environment, we developed a new surface-modification concept to control surface microbial contamination, particularly the development of bacterial colonies and biofilms.
In the past 10 years, there has been an increasing tendency to market consumer products - especially textiles - with an antimicrobial function. By far the majority of these antimicrobial treatments are potentially harmful to the environment or even to human beings. The previously used antimicrobial Triclosan is not recommended anymore for textile finishing as several negative effects on the health have been documented in studies on animals [1-3]. The antimicrobial technology that was used in this study is based on a nano-coating of antimicrobial molecules, well-organised and structured so that the surface of the substrate is protected from harmful germs with the guarantee that the antimicrobial network does not leach from the substrate and so does not damage the skin flora for applications close to the skin or the environment when the substrate is washed.
One key area of activity has been the technical development of products and processes for reducing contamination from manufactured articles, including textiles, during use. To a large part this is necessary for maintaining performance and function, often for health reasons, although sometimes for purely aesthetic effects. Nevertheless, by prolonging the useful life of an article, significant environmental benefits accrue, from the reduction in waste and the requirement for reduced cleaning in terms of frequency and energy / water use. Thus, easy-to-clean, soil release and antimicrobial properties are linked aspects that are of great importance affecting comfort and freshness in consumer apparel; reduction of spoilage or wastage during storage and transport; increase of the useful lifetime of articles; maintenance of health and avoidance of cross-contamination in medical textiles. These benefits further contribute to the overall goals of sustainable product development, and, through reducing in-built disposability, to save energy and to protect our water resources.
Industrial laundries have an obligation not only to clean work wear (aesthetic) but also to guarantee a microbiological cleanliness. Therefore, they tend to wash with very astringent cleaning and disinfecting agents such as chlorine or peroxides. Those treatments shorten the life of the garments and are high energy and water consumers. The increase in the wash durability of the antimicrobial treatment on work wear, led to increase of the service life of the goods, to reduction of the wash temperature (80 degrees Celsius down to 60 degrees Celsius) and furthermore, to the use of less astringent detergents and disinfectants. The same principle may be applied to linen for hospitals, for retirement homes and hotels.
Nosocomial infection is a serious issue for health care facilities. In the United States, the centres for disease control and prevention estimated roughly 1.7 million hospital-associated infections, from all types of microorganisms combined, cause or contribute to 99 000 deaths each year [4]. In Europe, the category of Gram-negative infections are estimated to account for two-thirds of the 25 000 deaths each year [4]. In the United Kingdom, a 8.2 % and in France a 5.4 % hospital-acquired (HAI) infection rate were published in 2006 [5, 6]. The nosocomial infection rate among adult patients in French intensive care units was 14.4 % in 2007 [7]. Nosocomial infections are estimated to make patients stay in the hospital four to five additional days in France. About 9000 people died in France each year (in 2004 - 2005) with a nosocomial infection, of which about 4200 would have survived without this infection [5, 8]. Since 2000, estimates show about a 6.7 % infection rate in Italy, i.e. between 450 000 and 700 000 patients, which caused between 4500 and 7000 deaths [9]. The annual number of nosocomial infections in Germany estimated for 2006 was between 400 000 and 600 000, the mortality attributable to them between 10 000 and 15 000 patients and the number of nosocomial MRSA infections about 14 000 [10]. In Germany, about 57 900 nosocomial infections are estimated to occur in intensive care units (ICUs) in hospitals each year [10-12].
Controlling infection in an environment which is contaminated by its very nature is very difficult and requires a multi-disciplinary approach. Today's actions in hospitals against nosocomial diseases are numerous; extensive procedures for hand washing are in place, jewellery must be removed before washing. But few decisions are taken about the environment, textile, and medical accessories although textiles are concerned in 17 % of nosocomial infections. In 2007, Dancer published a report which found that 'bed linens, hospital gowns and tables were all a more common source of superbugs than floors' [13]. Furthermore, the World Health Organisation (WHO) states that textiles 'act as a microbial harbour and offer ideal conditions for the proliferation of superbugs' [14].
So, the hospital laundry service is a key player. It is responsible for: selecting the type of fabrics to be used in different hospital areas, the distribution of work wear, developing policies for the collection and transport of dirty linen, defining the method for disinfecting, either before it is taken at the laundry or in the laundry itself, developing policies for the protection of clean linen from contamination during transport from the laundry to the area of use. Today, the use of very astringent chemicals to clean and to disinfect the linen is widespread. The washing temperature is set at very high temperature in order to guarantee the biological cleanliness of the textiles. The impact on the environment is severe: heavy load of chemicals in the waste water, high water consumption, high energy for the use of hot water and high energy for drying. The consequence on the linen itself is not much better: the textile fibre is quickly worn out by the heavy duty wash cycles and the life time of the linen is reduced. Finally, once the goods are completely disinfected after laundering, contamination during transport, warehousing, and use is unavoidable, with all the consequence. There is still confusion between the notion of disinfection at T0 and the ongoing contamination after T0 which can only be avoided by a permanent antimicrobial protection.
Therefore, the use of a highly durable antimicrobial treatment opens a completely new era for this market: longer life time for the goods, lower wash temperature, low load of disinfectant, and permanent protection during the use of the textile.
The economical and ecological impact are very high : one hospital bed represents on average 5 kg of linen/day, there are 500 000 hospitals beds and more then 700 000 beds in retirement homes just in France!
Historically, the brands and retailers launched only two collections a year (winter and summer). The trend is to move to four collections and some are thinking to a continuous process of renewing the collections in order to keep the consumers shopping. The other difficulty of this strategy is the management of the inventory; indeed, the quicker production of smaller batches allows one to keep the inventory low and to react quicker when some collections are successful. This dynamic management of the all textile chain is a real challenge. The difficulties for the complex extensive textile chain today are to react quickly enough. Each new textile substrate needs to be assessed and new formulations need to be tried and set-up. This leads currently to long development times and it is common to carry out development work for launch into the clothing market over a three-season period, that is, up to 18 months. By having the pull-through model in place, the communication between the specifiers and the mills can be accelerated and a better control of the technologies can be put in place. On the other hand, the surface activation technology is so versatile and flexible that the application of the functions (anti-odour, water repellent, soil release, etc.) is much easier because it is really a fully thoroughly designed application rather than a 'trial and error' process as currently today. It is thought that the time to market can be reduced to less then a year. This new flexibility allows the brands and retailers to reduce significantly the lot quantity and so the inventory which offers a new chance for the European textile industry relying mainly on SMEs.
Finally, the involvement of the SMEs of the consortium led to excellent opportunities for networking between the Partners. This is particularly valuable for SMEs which can boost the international presence of their businesses by this means. This close collaboration creates a business dynamic which would be much more difficult to initiate if the Partners were not working closely together inside the NANOBOND consortium.
References
[1] Position paper Nr. 031/2009 of Bundesinstitut für Risiskobewertung (BfR = German Federal Institute for Risk Assessment): 'BfR unterstützt Verwendungsverbot von Triclosan in Lebensmittelbedarfsgegenständen (BfR supports the ban of using Triclosan in food contact materials and consumer articles by law)', 12 June 2009
[2] Cherednichenko, Gennady et al., 'Triclosan impairs excitationcontraction coupling and Ca2+ dynamics in striated muscle', PNAS 109 (35), (2012), 14158-14163, doi: 10.1073/pnas.1211314109
[3] Spiegel-Online: 'Desinfektionsmittel schwächt Muskeln' (Disinfecting agent weakens muscles), 14 August 2012; http://www.spiegel.de/wissenschaft/medizin/0,1518,849943,00.html
[4] Pollack, Andrew, 'Rising Threat of Infections Unfazed by Antibiotics', New York Times, 27 February 2010
[5] http://en.wikipedia.org/wiki/Nosocomial_infection
[6] Anonymous, 'Survey finds 8.2 % of patients have healthcare associated infection. Results of third national prevalence survey of healthcare associated infection in England released', Press release of the Hospital Infection Society, 8 March 2007
[7] Réseau REA-Raisin 'Surveillance des infections nosocomiales en réanimation adulte. France, résultats 2002', Institut de veille sanitaire, September 2009
[8] Vasselle, Alain, 'Rapport sur la politique de lutte contre les infections nosocomiales', Office parlementaire d'évaluation des politiques de santé, June 2006, pp. 290
[9] Jozsef, Éric, 'L'Italie scandalisée par "l'hôpital de l'horreur"', Libération, 17 January 2007
[10] Gastmeier, P.; Geffers, C., 'Nosocomial infections in Germany. What are the numbers, based on the estimates for 2006?' Dtsch. Med. Wochenschr. 133 (21), (2008), 1111-5
[11] Geffers, C.; Gastmeier, P., 'Nosocomial Infections and Multidrug-resistant Organisms in Germany: Epidemiological Data from KISS (The Hospital Infection Surveillance System)', Dt. Ärzteblatt 108 (6), (2011), 87-92
[12] Dettenkofer, M.; Ammon, A.; Astagneau, P.; Dancer, S.J.; Gastmeier, P.; Harbarth, S.; Humphreys, H.; Kern, W.V.; Lyytikäinen, O.; Sax, H.; Voss, A.; Widmer, A.F. 'Infection control - a European research perspective for the next decade', J. Hosp. Infect. 77 (1), (2011), 7-10
[13] Dancer, St. J., 'Attention prescribers: be careful with antibiotics', The Lancet 369, (2007), 442-443
[14] Ducel, G.; Fabry, J.; Nicolle, L. (eds.), 'Prevention of Hospital Acquired Infection World Health Organisation', http://www.who.int/csr/resources/publications/whocdscsreph200212.pdf
List of websites:
http://www.nanobond.org
http://www.maedical.com
(i) the chemical activation of the fibre surface with a polymeric nano-coating for durable binding of functional molecules;
(ii) the effective incorporation of a selected functional finish for permanent modification of the textile properties, in the first instance a non-leaching antimicrobial agent;
(iii) the development of a universal technology applicable at any type of textiles and non fibrous materials.
The practical starting point of the NANOBOND project (see http://www.nanobond.org/ online) has been the existing surface activating polymer and non-leaching, antimicrobial coating technology developed by Devan and DPPT. The project aimed at the development of a sustainable surface activation technology based on the self-assembly power of a 'soft nano-technology' for the development of versatile, highly functional textile products adapted to the needs of consumers. The main emphasis has been on the development of inherently antimicrobial and multifunctional textiles due to the advance of nosocomial diseases in Europe. As alternative to commonly-used biocidal chemicals that are deliberately released from articles or surfaces and that are potentially environmentally harmful, we developed a new surface modification concept to control surface microbial contamination, particularly the development of bacterial colonies and biofilms.
New surface activating polymers based on the reaction of amines with epichlorohydrin have been developed. For this purpose, a low molecular weight azetidinium compound has been developed that contains a new bi-functional coupler and that can be added to various amine containing polymers. By this approach azetidinium functional groups are attached to the polymer backbone in a more quantitative and controlled way. In addition, further hydrophilic groups are introduced in the polymer backbone, which increases the hydrophilic / hydrophobic ratio of the polymer. It was found that the newly developed polymers are easily dispersed in water, while the surface affinity is retained. This is an improvement with respect to previously known surface activating polymers which are more difficult to be dispersed in water. Water solubility is an important aspect for textile finishing as textile treatment from solvents requires special facilities and is barely economically feasible in Europe. The evaluation of the developed polymers with regard to their applicability into the industrial process has been proofed. Thus, upscaling has been performed and the newly developed polymers have been applied onto textiles by the small and medium-sized enterprises (SMEs). First innovative textile products with improved antimicrobial activity have been developed by the SMEs.
Further approaches to develop multifunctional textiles included the development of flame retardant polymers and the integration of carrier systems, in particular microcapsules which contain active agents (here: antimicrobial agents, fragrances and phase change materials). The potential of the developed flame retardant polymers with regard to their effectiveness was demonstrated. Pre-treatment with surface activating polymers was found to improve uptake and fixation of microcapsules on textiles.
Studies on the influence of the structure and conformation of the newly developed polymers on their antimicrobial activity were performed with respect to their membrane affinity using different phospholipid Langmuir monolayer models and their inhibition potential against proliferation of E. coli, B. subtilis and S. aureus. The studies with the model membranes led to the result that micro-structural / conformational differences play a role in the interactions of polymers with the lipid layer. Furthermore, a structure-property relationship was established by analysing the antimicrobial activity of the polymers against E. coli, B. subtilis and S. aureus as function of the length of the alkyl chains at constant ratio of alkyl to cationic groups.
The final result of the project is the development of a universal, sustainable surface activation technology based on soft nano-coatings derived from specialised polymers that can themselves either create functionalised surfaces, or can provide a durable template from which functional properties can be built for the development of versatile, highly functional textiles and other products adapted to the needs of consumers. The main emphasis has been on the development of inherently antimicrobial and multifunctional textiles. The background for this has been the actual need to prevent nosocomial diseases in hospitals and nursing homes etc. Considerations of the safety of users, environmental damage and cost mitigated the 'over-treatment' approach and, thus, the focus has been on the development of non-leaching permanent antimicrobial coatings applicable to different types of textiles and non fibrous materials.
The assurance of high durability of the textiles treated in the developed process leads to a reduction in performance costs.
Project context and objectives:
Whilst the traditional European textile industry has experienced increasing competition from low-cost manufacturing countries, a new prosperous technical textile industry has grown, representing high value, technological manufacturers and producers. These companies remain economically viable because of the significant inputs of technical and quality elements that are more readily absorbed by the high-end applications in which their products and processes are used. Furthermore, technical textiles constitute an enabling technology for other important industries, e.g. light weight construction, automotive and medical technology.
Yet also in this high end market, industries face a permanent pressure to remain competitive. Evidently, continuous advancement of premium products alone may be not sufficient but industries must also refocus to medium- and low-tech large volume products by developing new, highly flexible production technologies and integrating fast feedback strategies along the production line from pre- to final products to rapidly respond to market demand. Such flexible production technologies must overcome the economic dilemmas between efficient large scale production and customer oriented product diversification on one side and minimum complexity versus elaborate optimisation of production processes on the other side.
This project addressed competitiveness in fibre and textile refinement in high wage European countries by the development of a technology that comprises easy diversification, fast adaptability, efficient use of recourses, and reduced complexity. The technology has been designed to be integrated in existing production lines and it is supported by a 'pull through' business model where the benefits of the technology are demonstrated on finished products in order to create a market pull situation through the production chain. The most important area of activity has been the technical development of products and processes for reducing contamination with microbes from manufactured articles, including textiles, during use. In the first line, this is necessary for health reasons, but also for maintaining performance and function of technical textiles. Nevertheless, by prolonging the useful life of an article, significant environmental benefits accrue, from the reduction in waste and the requirement for reduced cleaning in terms of frequency and energy / water use. Thus, easy-to-clean, soil release and antimicrobial properties are linked aspects that are of great importance affecting comfort and freshness in consumer apparel, reduction of spoilage or wastage during storage and transport, increase of the useful lifetime of articles, maintenance of health and avoidance of cross-contamination in medical textiles. These benefits further contribute to the overall goals of sustainable product development, and, through reducing in-built disposability, to reducing energy demands and the protection of our water resources. Another key area focuses on promoting adhesion in composite products with tailored mechanical and light weight properties.
The approach followed in this project has been based on a multifunctional bonding concept and does not rely on nano-particulates, but rather on molecular structuring at the nano-scale. It comprised the following:
- Adaptability to a wide range of consumer and industrial applications
The bonding technology can be extendible to use on any surface where performance properties may be required to maintain functionality in use. There are many similarities between textile surface properties and those of paper, leather and wood. Multi-functional performance of those substrates are also hot topics, for example, paper filters, leather for shoes and gloves, wood structures to be preserved from bad weather conditions. The developed surface activation technology can be 'spinned-off' to those related industries.
- Highly-tailored solutions by altering the characteristics of the polymeric nano-film
The NANOBOND project exploits self organisation to create nano-structured and functional surfaces that can impart multiple beneficial properties, or provide a template for anchoring further functional finishes. Examples include moisture management, fire retardancy, ultraviolet (UV).
- A responsive technology that adapts to the particular requirement for antimicrobial effect without 'swamping' the environment with the un-restrained release of antimicrobial agents, which is typical of other antimicrobial technologies
The NANOBOND technology, combined with an organo-silane antimicrobial product, creates an antimicrobial surface that functions by a physical rather than a chemical mode of action. Thus, antimicrobial performance is proportionated to specific needs, whether it is for apparel or for medical textiles or devices.
- Durability and effectiveness for the life of the goods has been clearly an important aspect in defining the sustainability credentials of the project. Articles treated with the NANOBOND / antimicrobial technology have a longer natural lifetime through protection against damage and spoilage. Thus, the initial cost of protection can be recouped through the increased longevity of treated articles.
- Low application levels during processing, to attain maximal performance and limiting the potential for release of chemical products
The permanent binding of the chemical finishes to textile surfaces further reduces the potential environmental harm because no chemical products are released to the environment during use, including laundering. The surface-bound nano-film approach to the development of performance finishes thus addresses important ecological issues.
- Easy application of the proposed technologies which will be integrated into the so-called 'wet processing' and does not require extensive modification or capital investment in expensive, sophisticated plant such as vacuum or Corona machinery
The novel technology was developed specifically to make use of the type of equipment classically employed and widely available in textile processing mills, including in SMEs, providing a drop-in technology. Thus, the time to market for these technologies, once developed, is rapid and brings a high-tech concept to a traditional industry without significant cost. This is one of the major benefits of this development. As a consequence of the technical achievements to be realised in the NANOBOND project, Devan and DPPT established a technological platform to which the other SME partners have access to develop their prototypes and to be trained in the use of the technologies. This platform is used as a pilot line to demonstrate the significant reduction in the time from laboratory studies to prototyping with an ultimate target 'less than 15 days'.
- The technology will be licensed to end-users under a process know-how technology transfer arrangement and Devan will manufacture and sell the developed chemicals. Industrial partners in the consortium will receive a free licence to use the technology in their respective field(s) of application. The licensing approach has two major advantages: good protection of the know-how and effective transfer of the technology to the user SMEs for optimum application. The licence fee will include the cost of education and training and royalties will be included in the chemical product prices.
- The focus on the differentiation between consumer groups (like sick people, older people, travelling people, sportspersons etc.) is in the responsibility of each SME in function of its respective market. Whilst, DCS and I-Care are able to focus the development of their products to the needs of individual consumers, the strategy of the other SME's is to develop differentiated products for diverse end-user groups which offers a degree of choice from a range of options. The technology allows easier integration of multi-functional properties. This means also that the SMEs differentiate their products not only from the competition but also have the ability to tailor products in function of the target consumer group.
In summary, the NANOBOND project aimed to develop a sustainable surface activation technology based on the self-assembly power of a 'soft nano-technology' for the development of versatile, highly functional textile products adapted to the needs of consumers. The main emphasis has been on the development of inherently antimicrobial and multi-functional textiles. As an alternative to commonly-used biocidal chemicals that are deliberately released from articles or surfaces and that are potentially environmentally harmful, a new surface modification concept to control surface microbial contamination, particularly the development of bacterial colonies and biofilms was proposed. This concept addresses:
(i) the adhesion of the microbial organisms to a surface;
(ii) the interruption of the biological functions that are vital for bacterial proliferation;
(iii) killing or controlling the microbial organisms that come into contact with the functional surface.
Beyond this, NANOBOND addressed also products and applications such as adhesion in composite products and non fibrous materials.
Project results:
As mentioned above, easy to clean, soil-release, soft touch and antimicrobial properties are linked aspects that are of great importance in sustainable product development, to save energy, ensure hygienic use and to protect our water resources from undesired contamination. Such properties can be obtained through surface functionalisation. Many surfaces, however, have no or only small numbers of reactive groups, thus the introduction of any functionality requires their prior activation. The typical method of surface activation is by 'physical' treatments using plasma or corona discharge, or in combination with, or as a pre-treatment for, chemical treatments. Such processes however, imply costly new equipment investment, the use of either vacuum (high energy cost) or an inert gas (cost and energy) or atmospheric costs (e.g. generation of ozone). Also, many of these treatments lead to unwanted changes in textile properties, such as an adverse change in handle or a reduction in strength.
In this field, the NANOBOND technology offers a more versatile alternative to a variety of application-specific methods for the fabrication of functional surfaces. The method applied in the project comprises the development of widely applicable covalently attached nano-coatings derived from specialised polymers that can themselves either create functionalised surfaces, or can provide a durable template from which functional properties can be built.
The basis of the research in NANOBOND focused on an a universal technology that will be applicable not only to flexible surfaces like polymers, foams, leather or paper but also to any hard surface like wood, concrete, metals, etc. Additionally, as it was planned to follow the 'drop in' technology approach, the use of processes and substances developed in the project will not require investments into sophisticated equipment from users. As the result, the time to market of products finished using new technology will be short.
One of the important surface modifications, which were studied in detail in the project, was prevention against build-up of bio-films on surfaces (antimicrobial). Consumer articles - including textiles - treated with antimicrobial agents are now widely available, and the use of antimicrobials increases the serviceability and longevity of treated articles. In addition, there are clearly potential comfort and aesthetic benefits, as well as health benefits in appropriate circumstances, for example for textile materials used in a variety of medical applications. But there are a number of key issues concerning effectiveness, human safety and environmental impact that must be addressed when considering the widespread use of such antimicrobial technologies. The maintenance of effectiveness after multiple uses and laundering is clearly a requirement of treated articles for the consumer, from the point of view of value for money and in terms of continuing to provide a performance benefit. The maintenance of effectiveness is of even more importance when considering medical textiles.
The most common approach to resolving the question of durability is to apply a high loading of the antimicrobial chemical to the treated article, by some means. During use, such compounds are leached from the article, a necessary process upon which their effectiveness relies as these compounds must be taken up or absorbed by micro-organisms. However, the compounds leached from the treated article in use - and during laundering - present unnecessary hazards. In terms of human health, the antimicrobial agent will cause destruction of harmless (indeed, beneficial) bacteria on the skin of the user. From an environmental viewpoint, uncontrolled release of antimicrobial agents into waste waters can have an adverse effect on effluent treatment plants, for example. Furthermore, release of antimicrobial chemicals in such a manner implies a finite effective life, which will vary considerably depending on the initial loading factor. In short, a more controlled and responsive technology is required, where the uncontrolled release of antimicrobial chemicals into the environment is avoided.
In the NANOBOND project, considerations of the safety of users, environmental damage and cost mitigate the 'over-treatment' approach and, thus, it was focused on the development of non-leaching permanent antimicrobial coatings applicable to different types of textiles and non fibrous materials.
The consortium possesses a non-leaching antimicrobial technology used for textiles based on the organo-silane compound commercialised as AEGIS, which formed the reference to the studies. The textiles finished with this compound show good resistance against a broad spectrum of Gram-positive and Gram-negative bacteria, as well as fungi (mould, mildew) yeasts and algae. The anti-fungal activity indirectly provides treated textiles with protection against house dust mites, an important allergic trigger for many people. Whilst sufficient for some applications, the durability of the coating needed to be increased for some applications, particularly use in medical textiles.
It has been observed, however, that the properties of AEGIS are significantly improved when the antimicrobial agent is co-applied with a surface activating polymer (Nanolink, also possessed by the consortium). The addition of such an activating polymer increases notably the durability and performance of the antimicrobial coatings to washing processes. For cotton, the antimicrobial protection using AEGIS coating begins to lose effectiveness after 20 wash cycles at 60 degrees Celsius, while the coatings additionally containing surface activating polymer show a high level of antimicrobial activity up to at least 30-40 wash cycles at 60 degrees Celsius. A similar tendency was noticed for synthetic textiles (polyester) where the introduction of surface activating polymers increased durability and activity of AEGIS coatings from 30 wash cycles at 60 degrees Celsius up to at least 50-60 cycles.
Through this project, the development of such coatings which will be stable on washing up to 100 or more washing cycles at elevated temperatures (at least 60 degrees Celsius) was planned. This should be achieved by detailed studies of the mechanisms which govern the adsorption / desorption processes of the surface activating polymer and antimicrobial agent. The assurance of such durability is very important in case of bedclothes for hospitals or hotels, surgeons' gowns and nurses' uniforms. These textiles need to be washed very often and if not sufficiently protected will lose their protective properties quickly and will be discarded which will lead to an increase in costs.
In the project, the mechanism of antimicrobial activity of the prepared coatings was to be evaluated, furthermore. In the literature, several models describe how antimicrobial polymers interact with bacterial cell walls and membranes, killing the bacteria. For instance, poly(ethylene imine) (PEI), a poly-cationic polymer, has been shown to make Gram-negative bacteria permeable to hydrophobic antibiotics and to detergents. Massive alterations in the outer membrane (OM) of PEI-treated bacteria were observed by electron microscopy of thin sections. It was also reported that the antibacterial activity of poly-cationic molecules is decreased or disappears completely upon crosslinking or upon being insolubilised. However, if the immobilised poly-cationic chains are sufficiently long and flexible to be able to penetrate the bacterial cell walls, the antibacterial properties persist. Yet, the biocidal mechanism of such polymers is still not clarified. It has been proposed that the polymer backbone acts as if it were a long alkyl chain that penetrates bacterial cell membranes. This was to be evaluated for the obtained coatings.
Ultimately, the focus of the project was to include other properties into surfaces such as moisture management, fire-resistance, easy-to-clean, UV-protection, softness etc.
Potential impact:
Strategic impact of the project
The project aimed to develop new knowledge-based technologies that address the need to enhance the technical performance of consumer articles, particularly apparel, sportswear and bedding. Further applications of the technology were to be evaluated in polymeric materials such as PU-foams for hospital or institutional applications and in textiles such as patient gowns for hospital use. Industrial (SME) partners active in the full range of these fields of application have been key participants in the project aiming at an incorporation of the developed technologies into their manufacturing processes or at the dissemination of the technology to other high-end users in selected industries. The project coordinator has been a research and development (R&D)-led company involved in developing highly-specialised chemical technologies for the textile industry. The project concept originated from the coordinating SME, which intended to develop a greater understanding of the influence of nano-coatings and to broaden their applicability. The research and technological development (RTD) partners have been chosen specifically because of their high level of sophistication in researching nano-coatings, polymers, antimicrobials and related topics. The other SME partners have been selected because of their involvement in the development of consumer products with a high technical content that allows differentiation from low-value mass-market goods. Furthermore, the outcomes of the project are applicable to medical textile products, where the need to impart specific performance such as antimicrobial behaviour is important to the quality and functionality of the goods. The other goal has been the transfer of the technology from textiles to the development of a new universal tool to finishing of non-fibrous elastic materials as well as the finishing of hard surfaces like paper, wood or leather.
The goal of the project has been the integration of new knowledge on nano- and material technologies with conventional production technologies in the traditional textile finishing sector and in textile cleaning, polymer processing and other industries.
The outcome of the project is a new concept in nano-structured polymeric coatings, which represents a novel application of 'soft nanotechnology'. These nano-structured coatings provide an activated surface for the further functionalisation of all textile goods to impart beneficial performance and health properties. The consortium has practical evidence to show that a functionalised polyether forms a coating on a textile surface that orients in such a way as to influence the surface properties of the textile fibre. It is known that there is an interaction between this polymer and an organo-silane with antimicrobial function, but the nature of that interaction is not known, and can be optimised by developing such an understanding. The organo-silane undergoes a self-polymerisation (condensation) on surfaces; it is believed that when co-applied, the structure of functionalised polyether may influence this self-polymerisation, which leads to an unexpected increase in antimicrobial performance and durability. In addition, other performance characteristics relating to comfort, health, aesthetics and sustainability may be introduced by using the nano-coating as a platform or template for further specific functionalisation. These surface modifications are considered to be 'passive' - there is no change in the basic form or function of the textile material, but the applied technology (antimicrobial, moisture management, fire resistance etc.) responds to a specific need and the localised environment in an appropriate way. The durability of the surface modifying nano-coating enables permanent performance benefits to be imparted for the life of the treated article, so increasing the useful life and sustainability of textile products. Furthermore, the bonded technology, in particular the developed coupler-modified polymers, ensure that no chemicals are released during use, reducing or eliminating the potential impact on human health and environmental safety.
The project integrated partners from a number of scientific disciplines and different end-user requirements, including those specialised in textile chemical applications, surface science, polymer synthesis, and end-users requiring specific high-tech solutions to issues relating to the microbial contamination of textile surfaces, as well as other performance requirements. The project outcomes provide commercial opportunities in a wide range of consumer-oriented goods, including apparel, sportswear and bedding, and in more specialised applications requiring a highly-tailored technical solution such as textiles for patient wear in hospitals and in foam 'comfort' pads. However, a common requirement of the SMEs is their need for high-performance technical solutions to maintain their competitiveness and innovative lead over inferior technologies from outside the EU.
The nano-coating technology requires an understanding of the surface properties of functional polymers and their interactions with other functional materials such as antimicrobials. Optimisation of the effects requires the design and manufacture of novel functional polymers encompassing the results of the early surface science studies. A key feature of the technology has been that it has been actually designed as a 'drop-in' technology. It is capable of application in conventional textile processing routes, not requiring investment in equipment or training. Thus, the technologies are capable of rapid implementation and integration into existing manufacturing processes.
The European textiles and clothing sector has suffered a drastic decline in activity in recent years, and continues to face intense competition from low-wage economies, particularly China and other Asian countries (see http://ec.europa.eu/enterprise/textile online). Nevertheless, considerable economic activity remains in the EU, concentrated on highly technical SMEs, representing a total turnover of 132 billion and a workforce of 1.83 million persons in 2011 (see http://www.euratex.org/news-and-publications/29 online). In 2011, there were about 146 000 companies within the EU-27 boundaries involved in the industry, of which 96 % are classified as SMEs (Euratex). The textile and clothing sector represents approx. 5 % of the jobs in the European manufacturing industry with an essential contribution of a female workforce (see http://www.etuf-tcl.org/index.php?s=6&rs=home&uid=689&lg=en#media online). European universities and research institutes also remain strong in the sciences and engineering related to the textile industry. For the sector to continue as a major revenue generator for the EU region, it must adapt and move towards technology- and knowledge-driven solutions in products and processes.
The market for technical textiles continues to develop and in these less price-sensitive applications the European industry is better able to compete, not only in terms of costs but, more importantly, in terms of technical ability, creativity and innovation. Within the category of technical textiles may be considered applications such as health-care, construction, geotextiles, protective clothing; in addition, with ever increasing demands by consumers for performance-enhancing clothing, we may also include sportswear, work-wear and other performance apparel in this category.
The global market for technical textiles was estimated to be worth 80 billion in 2005. A press release of Euratex aisbl from 18 June 2012 stated that the EU technical textile industry is a key development field for Europe, able to service world market(s) of more than 100 billions provided true worldwide market access is guaranteed and innovation is fostered in EU (see http://www.euratex.org/news-and-publications/29 online). The principal external markets are the United States, Switzerland and Turkey. The main producers of technical textiles within Europe are, in order, Germany, the United Kingdom, France, Belgium and Italy, the majority of which have been represented in this project.
It is clear that the strategic direction of the European textile industry must be towards developing solutions in these high added-value applications, which even so will require constant innovation to maintain a lead over the competitor regions. Companies involved in technical textiles invest a far higher proportion of turn-over in R&D (8-10 %), compared with a textile industry average (3-5 %) in order to remain competitive and such investment must increasingly be focussed on highly targeted R&D, working in close collaboration with EU universities and research centres to retain the technical lead that Europe presently enjoys over its competitors.
Societal impacts of the project
General
The industrialised textile industry has been located historically in certain regions in Europe and over the intervening period - during the last 200 years - this industrial activity was integrated into the social and cultural texture of the region and contributed strongly to its social and economical development. Certain regions became synonymous with distinct products of the textile industry, in particular through the marketing of high quality technical and fashionable products. These were important contributors to the EU balance of trade with the export of high added-value products. As the mass-production textile industry has declined in Europe, large-scale employment prospects have also diminished, but it is essential to retain significant levels of employment in the new, forward-looking niche market sectors of the industry. The importance of these high added-value niche applications has increased, and the continuation of the industry will increasingly rely on the transformation of the skills base in these traditional textile-producing regions.
The project addresses the most important Community societal objectives, as summarised below.
Employment
Technologies were developed suitable for high added-value textile applications which are more suited to production in high-wage countries in Europe. This helps to ensure the continued viability of technically advanced textile companies in high-wage countries in Europe.
Quality of life
Quality of life, health, safety and environment will be improved by reducing the negative impact of chemicals on water, air and soil pollution, and by saving natural resources such as water, whose management is of key importance for textile companies. Furthermore, the products developed will lead to less contamination of textiles with micro-bes and this will finally contribute to a reduction of nosocomial diseases in hospitals and other public institutions. Some of the developed products are foreseen for the market of the elderly aiming at an improvement of the life standard in houses for the elder and disabled people.
Knowledge-based society
The development of this new technology relies on a high level of technical knowledge and understanding of the underlying science, which has the potential to lead to further applications in non-related areas. Training and education of staff in the traditional textile industry will generate a new and highly technical workforce, better able to meet the future demands of this changing industry.
Niche markets
The project focused on technical niche markets where cost is less of a determining factor in the take-up of new technology. This is consistent with the aim of sustaining specialised industries in Europe and will be less prone to copying and substitution.
Intellectual protection
The technologies will be fully protected by patenting and licensing activities to ensure that uncontrolled dissemination of the acquired knowledge is prevented.
Dissemination and public engagement
Dissemination of the research activities and knowledge by demonstrating results on the tailored products, e.g. international conferences or in the academic teaching will help to foster dialogue with society and generate enthusiasm for science. Furthermore, the knowledge generated can be used as basis for future R&D cooperations or projects.
Economical impact for the SMEs
The basic objective has been the development of a novel bonding technology that permits the development of inherently antimicrobial and multi-functional textiles and other products where surface properties have an important role in determining performance. As an alternative to commonly-used biocidal chemicals that are deliberately released from articles or surfaces and that are potentially harmful to the environment, we developed a new surface-modification concept to control surface microbial contamination, particularly the development of bacterial colonies and biofilms.
In the past 10 years, there has been an increasing tendency to market consumer products - especially textiles - with an antimicrobial function. By far the majority of these antimicrobial treatments are potentially harmful to the environment or even to human beings. The previously used antimicrobial Triclosan is not recommended anymore for textile finishing as several negative effects on the health have been documented in studies on animals [1-3]. The antimicrobial technology that was used in this study is based on a nano-coating of antimicrobial molecules, well-organised and structured so that the surface of the substrate is protected from harmful germs with the guarantee that the antimicrobial network does not leach from the substrate and so does not damage the skin flora for applications close to the skin or the environment when the substrate is washed.
One key area of activity has been the technical development of products and processes for reducing contamination from manufactured articles, including textiles, during use. To a large part this is necessary for maintaining performance and function, often for health reasons, although sometimes for purely aesthetic effects. Nevertheless, by prolonging the useful life of an article, significant environmental benefits accrue, from the reduction in waste and the requirement for reduced cleaning in terms of frequency and energy / water use. Thus, easy-to-clean, soil release and antimicrobial properties are linked aspects that are of great importance affecting comfort and freshness in consumer apparel; reduction of spoilage or wastage during storage and transport; increase of the useful lifetime of articles; maintenance of health and avoidance of cross-contamination in medical textiles. These benefits further contribute to the overall goals of sustainable product development, and, through reducing in-built disposability, to save energy and to protect our water resources.
Industrial laundries have an obligation not only to clean work wear (aesthetic) but also to guarantee a microbiological cleanliness. Therefore, they tend to wash with very astringent cleaning and disinfecting agents such as chlorine or peroxides. Those treatments shorten the life of the garments and are high energy and water consumers. The increase in the wash durability of the antimicrobial treatment on work wear, led to increase of the service life of the goods, to reduction of the wash temperature (80 degrees Celsius down to 60 degrees Celsius) and furthermore, to the use of less astringent detergents and disinfectants. The same principle may be applied to linen for hospitals, for retirement homes and hotels.
Nosocomial infection is a serious issue for health care facilities. In the United States, the centres for disease control and prevention estimated roughly 1.7 million hospital-associated infections, from all types of microorganisms combined, cause or contribute to 99 000 deaths each year [4]. In Europe, the category of Gram-negative infections are estimated to account for two-thirds of the 25 000 deaths each year [4]. In the United Kingdom, a 8.2 % and in France a 5.4 % hospital-acquired (HAI) infection rate were published in 2006 [5, 6]. The nosocomial infection rate among adult patients in French intensive care units was 14.4 % in 2007 [7]. Nosocomial infections are estimated to make patients stay in the hospital four to five additional days in France. About 9000 people died in France each year (in 2004 - 2005) with a nosocomial infection, of which about 4200 would have survived without this infection [5, 8]. Since 2000, estimates show about a 6.7 % infection rate in Italy, i.e. between 450 000 and 700 000 patients, which caused between 4500 and 7000 deaths [9]. The annual number of nosocomial infections in Germany estimated for 2006 was between 400 000 and 600 000, the mortality attributable to them between 10 000 and 15 000 patients and the number of nosocomial MRSA infections about 14 000 [10]. In Germany, about 57 900 nosocomial infections are estimated to occur in intensive care units (ICUs) in hospitals each year [10-12].
Controlling infection in an environment which is contaminated by its very nature is very difficult and requires a multi-disciplinary approach. Today's actions in hospitals against nosocomial diseases are numerous; extensive procedures for hand washing are in place, jewellery must be removed before washing. But few decisions are taken about the environment, textile, and medical accessories although textiles are concerned in 17 % of nosocomial infections. In 2007, Dancer published a report which found that 'bed linens, hospital gowns and tables were all a more common source of superbugs than floors' [13]. Furthermore, the World Health Organisation (WHO) states that textiles 'act as a microbial harbour and offer ideal conditions for the proliferation of superbugs' [14].
So, the hospital laundry service is a key player. It is responsible for: selecting the type of fabrics to be used in different hospital areas, the distribution of work wear, developing policies for the collection and transport of dirty linen, defining the method for disinfecting, either before it is taken at the laundry or in the laundry itself, developing policies for the protection of clean linen from contamination during transport from the laundry to the area of use. Today, the use of very astringent chemicals to clean and to disinfect the linen is widespread. The washing temperature is set at very high temperature in order to guarantee the biological cleanliness of the textiles. The impact on the environment is severe: heavy load of chemicals in the waste water, high water consumption, high energy for the use of hot water and high energy for drying. The consequence on the linen itself is not much better: the textile fibre is quickly worn out by the heavy duty wash cycles and the life time of the linen is reduced. Finally, once the goods are completely disinfected after laundering, contamination during transport, warehousing, and use is unavoidable, with all the consequence. There is still confusion between the notion of disinfection at T0 and the ongoing contamination after T0 which can only be avoided by a permanent antimicrobial protection.
Therefore, the use of a highly durable antimicrobial treatment opens a completely new era for this market: longer life time for the goods, lower wash temperature, low load of disinfectant, and permanent protection during the use of the textile.
The economical and ecological impact are very high : one hospital bed represents on average 5 kg of linen/day, there are 500 000 hospitals beds and more then 700 000 beds in retirement homes just in France!
Historically, the brands and retailers launched only two collections a year (winter and summer). The trend is to move to four collections and some are thinking to a continuous process of renewing the collections in order to keep the consumers shopping. The other difficulty of this strategy is the management of the inventory; indeed, the quicker production of smaller batches allows one to keep the inventory low and to react quicker when some collections are successful. This dynamic management of the all textile chain is a real challenge. The difficulties for the complex extensive textile chain today are to react quickly enough. Each new textile substrate needs to be assessed and new formulations need to be tried and set-up. This leads currently to long development times and it is common to carry out development work for launch into the clothing market over a three-season period, that is, up to 18 months. By having the pull-through model in place, the communication between the specifiers and the mills can be accelerated and a better control of the technologies can be put in place. On the other hand, the surface activation technology is so versatile and flexible that the application of the functions (anti-odour, water repellent, soil release, etc.) is much easier because it is really a fully thoroughly designed application rather than a 'trial and error' process as currently today. It is thought that the time to market can be reduced to less then a year. This new flexibility allows the brands and retailers to reduce significantly the lot quantity and so the inventory which offers a new chance for the European textile industry relying mainly on SMEs.
Finally, the involvement of the SMEs of the consortium led to excellent opportunities for networking between the Partners. This is particularly valuable for SMEs which can boost the international presence of their businesses by this means. This close collaboration creates a business dynamic which would be much more difficult to initiate if the Partners were not working closely together inside the NANOBOND consortium.
References
[1] Position paper Nr. 031/2009 of Bundesinstitut für Risiskobewertung (BfR = German Federal Institute for Risk Assessment): 'BfR unterstützt Verwendungsverbot von Triclosan in Lebensmittelbedarfsgegenständen (BfR supports the ban of using Triclosan in food contact materials and consumer articles by law)', 12 June 2009
[2] Cherednichenko, Gennady et al., 'Triclosan impairs excitationcontraction coupling and Ca2+ dynamics in striated muscle', PNAS 109 (35), (2012), 14158-14163, doi: 10.1073/pnas.1211314109
[3] Spiegel-Online: 'Desinfektionsmittel schwächt Muskeln' (Disinfecting agent weakens muscles), 14 August 2012; http://www.spiegel.de/wissenschaft/medizin/0,1518,849943,00.html
[4] Pollack, Andrew, 'Rising Threat of Infections Unfazed by Antibiotics', New York Times, 27 February 2010
[5] http://en.wikipedia.org/wiki/Nosocomial_infection
[6] Anonymous, 'Survey finds 8.2 % of patients have healthcare associated infection. Results of third national prevalence survey of healthcare associated infection in England released', Press release of the Hospital Infection Society, 8 March 2007
[7] Réseau REA-Raisin 'Surveillance des infections nosocomiales en réanimation adulte. France, résultats 2002', Institut de veille sanitaire, September 2009
[8] Vasselle, Alain, 'Rapport sur la politique de lutte contre les infections nosocomiales', Office parlementaire d'évaluation des politiques de santé, June 2006, pp. 290
[9] Jozsef, Éric, 'L'Italie scandalisée par "l'hôpital de l'horreur"', Libération, 17 January 2007
[10] Gastmeier, P.; Geffers, C., 'Nosocomial infections in Germany. What are the numbers, based on the estimates for 2006?' Dtsch. Med. Wochenschr. 133 (21), (2008), 1111-5
[11] Geffers, C.; Gastmeier, P., 'Nosocomial Infections and Multidrug-resistant Organisms in Germany: Epidemiological Data from KISS (The Hospital Infection Surveillance System)', Dt. Ärzteblatt 108 (6), (2011), 87-92
[12] Dettenkofer, M.; Ammon, A.; Astagneau, P.; Dancer, S.J.; Gastmeier, P.; Harbarth, S.; Humphreys, H.; Kern, W.V.; Lyytikäinen, O.; Sax, H.; Voss, A.; Widmer, A.F. 'Infection control - a European research perspective for the next decade', J. Hosp. Infect. 77 (1), (2011), 7-10
[13] Dancer, St. J., 'Attention prescribers: be careful with antibiotics', The Lancet 369, (2007), 442-443
[14] Ducel, G.; Fabry, J.; Nicolle, L. (eds.), 'Prevention of Hospital Acquired Infection World Health Organisation', http://www.who.int/csr/resources/publications/whocdscsreph200212.pdf
List of websites:
http://www.nanobond.org
http://www.maedical.com