Textination Newsline

Nonwoven production received more attention than ever before from the general public in Corona times, because the technical textile is crucial for infection protection. The ultra-fine nonwoven products are manufactured in so-called meltblown processes. A cross-departmental team at the Fraunhofer Institute for Industrial Mathematics ITWM in Kaiserslautern is optimizing the entire production chain in the »ProQuIV« project. Simulations help to guarantee the product quality of the filter material despite fluctuations in production.

The abbreviation »ProQuIV« stands for »Production and Quality Optimization of Nonwoven Infection Protection Clothing«. This is because bottlenecks in the production of these materials were particularly evident at the beginning of the Covid 19 crisis. For the meltblown nonwovens, this optimization of the product quality is also particularly difficult because the textiles react very sensitively to fluctuations in the manufacturing processes and material impurities.

Digital Twin Keeps an Eye on the Big Picture
»Meltblown« is the name of the industrial manufacturing process whose ultra-fine fiber nonwovens are responsible for providing the crucial filtering function in face masks. In this process, the molten polymer is forced through nozzles into a forward-flowing, high-speed stream. It is stretched and cooled in a highly turbulent air flow.

»The overall process of filter media production – from the polymer melt to the filter medium – presents a major challenge in simulation,« explains Dr. Konrad Steiner, head of the »Flow and Materials Simulation« department. »In the project, we kept the big picture in mind and developed a completely integrated evaluation chain as a digital twin. In doing so, we take several key components into account at once: We simulate the typical production processes of nonwovens, the formation of the fiber structures and then the material properties – here, in particular, the filter efficiency. This allows us to quantitatively evaluate the influences of the manufacturing process on the product properties.« In each of these individual areas, Fraunhofer ITWM and its experts are among the leading research groups internationally.

Homogeneity of the Material – Fewer Clouds in the Simulation Sky
In the meltblown process, a key factor is the behavior of the filaments in the turbulent, hot and fast air flow. The properties of the filaments are strongly influenced by this air flow. The quality of the filaments – and thus the quality of the nonwovens – is influenced by many factors. Dr. Dietmar Hietel, head of the »Transport Processes« department, knows what this means more precisely in practice. His team has been working at Fraunhofer ITWM for years on the simulation of various processes involving filaments, threads, and fibers. »The focus of the project is the so-called cloudiness, i.e. the non-uniformity of the fiber distributions in the nonwoven,« explains Hietel. »We are investigating the question: How homogeneous is the fabric? Because the quality of the products can be greatly improved if we increase the uniformity. Our simulations help figure out how to do that.«

Objective Evaluation of the Homogeneity of Nonwovens
The researchers also use appropriate image analysis techniques to quantify this cloudiness. The power spectrum plays a special role here. »The cloudiness index (CLI) describes homogeneity complementary to local basis weight and its variance,« describes Dr. Katja Schladitz. She brings her expertise in image processing to the project. »Our CLI ensures a robust assessment of the homogeneity and can thus be used for different material classes and imaging techniques to be used as an objective measure.« The frequencies that go into the CLI calculation can be chosen so that the CLI is meaningful for the particular application area.

Filtration: How Efficient Are the Filters?
For the upscaling to industrial processes such as mask production, the ITWM expertise in filters is also included in the project. The »Filtration and Separation« team led by Dr. Ralf Kirsch has been working for years on the mathematical modeling and simulation of various separation processes.

»What's special about this project is that we calculated the efficiency of the filters for fluctuations of varying degrees in the fiber volume fraction,« emphasizes Kirsch. »This allows us to specify up to what level of cloudiness the required filter efficiency can be achieved at all.« As a current example of this, the figure depicts in the graphic the efficiency of a filter material for N95 masks as a function of the inhomogeneity of the nonwoven.

ITMW Methods Support Across the Entire Process Chain
In »ProQuIV«, digital twins and calculations from Fraunhofer ITWM support a holistic view and better understanding of the processes. The production of technical textiles thus not only becomes more efficient, but the nonwovens can be developed virtually without having to realize this in advance in a test facility. In this way, production capacities can be increased while maintaining or even increase the quality. Together with long-term partners from industry, the research can be put into practice quickly and efficiently.

Simulations save textile companies experiments, allow new insights, enable systematic parameter variations and solve upscaling problems that can otherwise lead to bad investments during the transition from laboratory plant to industrial plant. However, virtual implementation of nonwoven production also opens up new opportunities for optimization at other levels. For example, acoustic insulating nonwovens or even hygiene nonwovens can also be optimized in terms of their product quality precisely with regard to the material properties to be achieved – while taking into account the process fluctuations that occur.

The project is part of the Fraunhofer-Gesellschaft's »Fraunhofer versus Corona« program and was completed in April 2021. The results will flow into several follow-up projects with the nonwovens industry.

With “Next Horizons”, Heimtextil is presenting its design forecast for the new season 2022/23 – analysed by international trend researchers and packed with valuable inspiration and inspiring content. The new trend themes take sustainability and resource conservation in the heart of their approach. The international trade fair for home and contract textiles takes place from 11 to 14 January 2022 in Frankfurt am Main.

Three international design agencies form the Heimtextil Trend Council. Together, they develop a well-founded global vision of the coming interior trends. Alongside the Heimtextil Trend Council, Heimtextil management has established a trend forecast for the coming season and presented it live via an online conference on 1 September 2021 from Frankfurt am Main. Trend Council members Anja Bisgaard Gaede from SPOTT trends & business, Anne Marie Commandeur from Stiljinstituut Amsterdam and Kate Franklin and Caroline Till from London studio FranklinTill shared their insights into the future of the industry. Designers, interior architects and decorators get inspired by the design forecast for the new season.

Next Horizons: long-term and circular mindset
The Next Horizons are not a fixed goal or a finish line – they are mindsets. These are made up of long-term thinking, accepting that the best way to impact the world is simply not to. Paradoxically, we have begun our transition to sustainability by addressing the problems within our manufactured system instead of transforming our approach to not create waste or imbalance. Transforming our nexus begins with accepting our economies are embedded within nature. The composition of design should be accessed, made and recirculated in tune with a long-term and circular mindset and simply not create waste. The Heimtextil Trends 22/23 “Deep Nature”, “Hyper Nature”, “Beyond Identity” and “Empowered Identity” explore these new mindsets for “Next Horizons”.

Heimtextil Trends in a new digital format
With “Next Horizons”, Heimtextil is breaking new ground and, for the first time, making trend information fully available in a digital format. The brand-new online platform of Heimtextil introduces the trends richly illustrated via colours, short films, bespoke imagery, key designer features and a soundtrack. The new online platform and all trend activities are directed by SPOTT trends & business from Denmark.

The Future Materials Library is now digital
Curated by Futures Agency FranklinTill, The Future Materials Library was launched in 2020 and is now available online at www.heimtextil-trends.com/future. This collection of exciting interior material innovations from around the world celebrates radical designers, innovative manufacturers and environmentally conscious producers who are helping to turn the current, linear system of production and consumption into a circular model.

Heimtextil Trends 22/23 – overview
Deep Nature – Rebalance by relearning
“Deep Nature” explores our ecosystem’s strategies: it’s our legacy and future all at once. We need to relearn and give into untamed texture, slow process, natural structures and living colours. “Deep Nature” is a long-term transformation and relearning process which gives us the ability to rebalance the natural world for a regenerative future. The colour scale for “Deep Nature” has a harmonious and soft expression used for untamed patternmaking. Mouldy, herbal tones and delicate tones of blue and rouge create a calm, tonal, and earthy approach.

Hyper Nature – Reconnect with nature via technology
“Hyper Nature” is about reconnecting to nature through technology. The theme is a digital facilitator of nature’s blueprint, fusing technology and nature for a protopia state and creating a better tomorrow step by step. Responsive materials, technical fibres, fluid patterns and microscopic structure describes materials and textiles for “Hyper Nature”. Bioscience brings inspiration to colours of both bright and lucid and blurred nuances of green and grey. Reflections and artificial light create new perceptions of nature-based colours. Coral, salmon and light raspberry are highlights.

Beyond Identity – Values more than physical attributes
“Beyond Identity” addresses the future with hopeful messages and soft and powerful defiance toward existing norms, leaving identity in flux. For the world of home interiors and textiles “Beyond Identity” works with recycled synthetic fabric, vintage silk and satin, natural-coloured textiles and new cellulose-based textiles. They are formed via the uncontrolled colouration process of a pastel-coloured look resembling the constant flux of identity. The colours scale for “Beyond Identity” features a range of pastels, complemented with a familiar grey and pale khaki as muted transferral colours.

Empowered Identity – Empower artisanship to sustain culture
“Empower Identity” is about creating sustainable cultural connections, renewing artisan sources of inspiration in a collaborative way. Empowering Identity encourages forming new connections between heritage cultures and future generations. Recycled and heritage textiles combined with textile craft techniques as tufting, embroidered appliqué and Cross-stitch are in focus in “Empower Identity”. Primary colours resemble their colour pigment origins to support the heritage expression of the theme. Sparks of coral and a greyed lilac accompany these primary tones. Multi-coloured usage is key.