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Aerogel (c) Outlast Technologies GmbH
31.01.2023

Aerogel: Frozen Smoke for Clothing and Work Safety

Comprised of up to 99.8 percent air, aerogel is the lightest solid in the world. The material, which is also called “frozen smoke” due to its appearance and physical properties, exhibits extremely low heat conductivity which exceeds other insulations many times over. This is why NASA has already been using aerogel for aerospace projects for many years.

Despite this, it has not been possible to bind the material to textiles in a high concentration and enable straightforward further processing over the roughly 90-year history of the material. Outlast Technologies GmbH has developed an innovative process - a patent has already been filed for -  for permanently adhering large amounts of aerogel to different media, like nonwoven fabric, felt and composites materials. Their original properties are retained throughout, so they can easily be further processed using conventional production methods.

Comprised of up to 99.8 percent air, aerogel is the lightest solid in the world. The material, which is also called “frozen smoke” due to its appearance and physical properties, exhibits extremely low heat conductivity which exceeds other insulations many times over. This is why NASA has already been using aerogel for aerospace projects for many years.

Despite this, it has not been possible to bind the material to textiles in a high concentration and enable straightforward further processing over the roughly 90-year history of the material. Outlast Technologies GmbH has developed an innovative process - a patent has already been filed for -  for permanently adhering large amounts of aerogel to different media, like nonwoven fabric, felt and composites materials. Their original properties are retained throughout, so they can easily be further processed using conventional production methods.

The fabrics sold under the Aersulate name are only 1 to 3 mm thick and achieve very high insulation values which are largely retained even under pressure and in moist conditions. Despite their high performance, they are still soft and can be used for shoes, clothing and work safety products, as well as for sleeping bags and technical applications.
 
“Thanks to its extraordinary physical properties, NASA has already been using aerogel for many years,” remarked Volker Schuster, Head of Research and Development at Outlast Technologies. “For example, for the insulation of its Mars rovers and for capturing dust from the tail of a comet during the Stardust mission,” he continued. Since the development of aerogel by American scientist and chemical engineer Samuel Stephens Kistler in 1931, no-one had been able to apply the versatile material to textiles in large amounts without changing their original properties, despite intensive research. This means that the products were often not only very rigid, but made processing with conventional production methods impossible due to their high degree of dust abrasion. With the newly developed Aersulate technology, which was presented for the first time in June 2022, the Heidenheim-based specialist for textile thermoregulation is opening a different chapter in insulation history.

High-performance insulation just 1 to 3 mm thick
“The consistency of aerogel can be best described as liquid dust particles which spread uncontrollably throughout a room within seconds thanks to their minimal thickness,” explained Schuster. “This is why processing is a big challenge.” Outlast Technologies has managed, after a development period of around five years, to bring an innovative process involving the adhering of aerogel between multiple layers of material to market maturity. Depending on the area of application, nonwoven fabric, felt and different composite materials can be used as the media. What is special here is that the properties of the respective textiles are not adversely affected by the Aersulate technology, meaning that they can easily be further processed with conventional means and under industrial conditions despite their acquired thermal properties.
 
As a silicate-based solid, aerogel is obtained from natural quartz sand, yet exhibits a density over 1,000 times lower than glass manufactured from the same raw material. The extraordinary thermo-insulating properties of the material are thanks to its extremely porous structure, which enables it to be composed of up to 99.8 percent air.
 
“One liter of aerogel weighs just 50 g,” explained Schuster. “Just 10 g of the material has the same surface area as a soccer field, though.” Thanks to these properties, Aersulate textiles exceed all other previously known insulation materials in terms of performance, despite the fact that they are only 1 to 3 mm thick. Tests carried out by the German Institute for Textile and Fiber Research in Denkendorf (DITF) using the Alambeta method showed that the thermal resistance of an Aersulate fleece is more than double that of a conventional fleece of the same thickness. Add to this the fact that the thermo-insulating properties of Aersulate products remain high despite pressure and wetness, while they decrease enormously with other conventional materials like felt and polyurethane foam (PU) under these conditions.

Work safety and functional clothing with Aersulate
Thanks to the textile medium, thin Aersulate products are especially suitable for the shoe and clothing industry, as well as all areas of work safety. The user benefits from different properties, depending on the intended use. “With a glove made of Aersulate just 1 mm thick, you can put your hand into boiling water without being scalded, for example,” explained Schuster. “The material’s extremely hydrophobic properties play quite literally into our hands here.” In the case of knee patches on work and functional pants, as well as shoes and soles, on the other hand, the material properties also become relevant when compression occurs. This is because the thermo-insulation properties of other materials would be reduced little by little due to moisture from the outside and sweat from the inside on the one hand, and by the continual influence of body weight on the other.
          
In addition to the human body, luggage and technical devices can also be protected from extreme temperatures and the effects of weather with Aersulate. For this purpose, corresponding cell phone or equipment pockets could be sewn into garments, for example, to maintain their battery life even at very cold outside temperatures and to safeguard the devices from overheating in case of high heat exposure. “With the broad range of possible textile medium materials, Aersulate is suitable for all applications requiring high thermal resistance on the one hand, where only a little space is available and both compression and moisture can be expected on the other,” said Schuster in summary.

Source:

Outlast Technologies / Textination

(c) Continuum
24.01.2023

... and they actually can be recycled: Wind Turbine Blades

The Danish company Continuum Group ApS with its subsidiary companies in Denmark (Continuum Aps) and the UK (Continuum Composite Transformation (UK) Limited) wants to give end-of-life wind blades and composites a new purpose, preventing them going to waste. The goal is to reduce the amounts of CO2 emitted to the atmosphere by the current waste streams, delivering a value to Europe’s Net Zero efforts.

Continuum states that it ensures all wind turbine blades are 100% recyclable and plans to build industrial scale recycling factories across Europe.

Net zero is the phrase on everyone’s lips, and as 2030 rapidly approaches we constantly hear updates about wind energy generating renewable energy that powers millions of European homes – but what happens when those turbine blades reach the end of their lifespan?

The Danish company Continuum Group ApS with its subsidiary companies in Denmark (Continuum Aps) and the UK (Continuum Composite Transformation (UK) Limited) wants to give end-of-life wind blades and composites a new purpose, preventing them going to waste. The goal is to reduce the amounts of CO2 emitted to the atmosphere by the current waste streams, delivering a value to Europe’s Net Zero efforts.

Continuum states that it ensures all wind turbine blades are 100% recyclable and plans to build industrial scale recycling factories across Europe.

Net zero is the phrase on everyone’s lips, and as 2030 rapidly approaches we constantly hear updates about wind energy generating renewable energy that powers millions of European homes – but what happens when those turbine blades reach the end of their lifespan?

Currently the general answer is to put them into landfill or co-process them into cement, but neither is planet friendly. Many countries in Europe look to ban landfill from 2025, so this option is likely to be eliminated in the near future.

Continuum provides an alternative: When the end of their first life arrives, Continuum recycles them into new, high performing composite panels for the construction, and related industries. The vision of the Danes: Abandon the current landfilling, and drastically reduce CO2 emitted during currently applied incineration & co-processing in cement factories by 100 million tons by 2050, via their mechanical composite recycling technology and their industrial scale factories.  

The technology is proven, patented, and ready to go, says Reinhard Kessing, co-founder and CTO of Continuum Group ApS, who has spent more than 20 years of research and development in this field, and advanced the reclamation of raw materials from wind blades and other composite products and transformation of these materials into new, high performing panel products.

By working with partners, Continuum’s cost-effective solution covers end-to-end logistics and processes. This spans from the collection of the end-of-life blades through to the reclamation of the pure clean raw materials and then the remanufacturing of all those materials into high value, highly performing, infinitely recyclable composite panels for the construction industry or the manufacture of many day-to-day products such as facades, industrial doors, and kitchen countertops. The panels are 92% recycled blade material and are said to outperform competing products.

Nicolas Derrien: Chief Executive Officer of Continuum Group ApS said: “We need solutions for the disposal of wind turbine blades in an environmentally friendly manner, we need it now, and we need it fast, and this is where Continuum comes in! As a society we are rightly focussed on renewable energy production, however the subject of what to do with wind turbine blades in the aftermath of that production has not been effectively addressed. We’re changing that, offering a recycling solution for the blades and a construction product that will outperform most other existing construction materials and be infinitely recyclable, and with the lowest carbon footprint in its class.”

Martin Dronfield, Chief Commercial Officer of Continuum Group ApS and Managing Director of Continuum Composite Transformation (UK) Ltd, adds: “We need wind energy operators & developers across Europe to take a step back and work with us to solve the bigger picture challenge. Continuum is offering them a service which won’t just give their business complete and sustainable circularity to their operations but help protect the planet in the process.“

Each Continuum factory in Europe will have the capacity to recycle a minimum of 36,000 tons of end-of-life turbine blades per year and feed the high value infinitely recyclable product back into the circular economy by 2024/25.

Due to an investment by Climentum Capital and a grant from the UK’s ‘Offshore Wind Growth Partnership’, Continuum are planning for the first of six factories in Esbjerg to be operational by the end of 2024 and for a second factory in the United Kingdom to follow on just behind it. After that they are looking to build another four in France, Germany, Spain, and Turkey by 2030.

As part of their own pledge to promote green behaviour, Continuum have designed their factories to be powered by only 100% green energy and to be zero carbon emitting environments; meaning no emissions to air, no waste fluids to ground, and no carbon fuel combustion.

Source:

Continuum / Textination

North Carolina State University
17.01.2023

Embroidery as Low-Cost Solution for Making Wearable Electronics

Embroidering power-generating yarns onto fabric allowed researchers to embed a self-powered, numerical touch-pad and movement sensors into clothing. The technique offers a low-cost, scalable potential method for making wearable devices.

“Our technique uses embroidery, which is pretty simple – you can stitch our yarns directly on the fabric,” said the study’s lead author Rong Yin, assistant professor of textile engineering, chemistry and science at North Carolina State University. “During fabric production, you don’t need to consider anything about the wearable devices. You can integrate the power-generating yarns after the clothing item has been made.”

Embroidering power-generating yarns onto fabric allowed researchers to embed a self-powered, numerical touch-pad and movement sensors into clothing. The technique offers a low-cost, scalable potential method for making wearable devices.

“Our technique uses embroidery, which is pretty simple – you can stitch our yarns directly on the fabric,” said the study’s lead author Rong Yin, assistant professor of textile engineering, chemistry and science at North Carolina State University. “During fabric production, you don’t need to consider anything about the wearable devices. You can integrate the power-generating yarns after the clothing item has been made.”

In the study published in Nano Energy, researchers tested multiple designs for power-generating yarns. To make them durable enough to withstand the tension and bending of the embroidery stitching process, they ultimately used five commercially available copper wires, which had a thin polyurethane coating, together. Then, they stitched them onto cotton fabric with another material called PTFE.

“This is a low-cost method for making wearable electronics using commercially available products,” Yin said. “The electrical properties of our prototypes were comparable to other designs that relied on the same power generation mechanism.”

The researchers relied on a method of generating electricity called the “triboelectric effect,” which involves harnessing electrons exchanged by two different materials, like static electricity. They found the PTFE fabric had the best performance in terms of voltage and current when in contact with the polyurethane-coated copper wires, as compared to other types of fabric that they tested, including cotton and silk. They also tested coating the embroidery samples in plasma to increase the effect.

“In our design, you have two layers – one is your conductive, polyurethane-coated copper wires, and the other is PTFE, and they have a gap between them,” Yin said. “When the two non-conductive materials come into contact with each other, one material will lose some electrons, and some will get some electrons. When you link them together, there will be a current.”
Researchers tested their yarns as motion sensors by embroidering them with the PTFE fabric on denim. They placed the embroidery patches on the palm, under the arm, at the elbow and at the knee to track electrical signals generated as a person moves. They also attached fabric with their embroidery on the insole of a shoe to test its use as a pedometer, finding their electrical signals varied depending on whether the person was walking, running or jumping.

Lastly, they tested their yarns in a textile-based numeric keypad on the arm, which they made by embroidering numbers on a piece of cotton fabric, and attaching them to a piece of PTFE fabric. Depending on the number that the person pushed on the keypad, they saw different electrical signals generated for each number.

“You can embroider our yarns onto clothes, and when you move, it generates an electrical signal, and those signals can be used as a sensor,” Yin said. “When we put the embroidery in a shoe, if you are running, it generates a higher voltage than if you were just walking. When we stitched numbers onto fabric, and press them, it generates a different voltage for each number. It could be used as an interface.”

Since textile products will inevitably be washed, they tested the durability of their embroidery design in a series of washing and rubbing tests. After hand washing and rinsing the embroidery with detergent, and drying it in an oven, they found no difference or a slight increase in voltage. For the prototype coated in plasma, they found weakened but still superior performance compared with the original sample. After an abrasion test, they found that there was no significant change in electrical output performance of their designs after 10,000 rubbing cycles.

In future work, they plan to integrate their sensors with other devices to add more functions.
“The next step is to integrate these sensors into a wearable system,” Yin said.

The study, “Flexible, durable and washable triboelectric yarn and embroidery for self-powered sensing and human-machine interaction,” was published online in Nano Energy. Co-authors included Yu Chen, Erdong Chen, Zihao Wang, Yali Ling, Rosie Fisher, Mengjiao Li, Jacob Hart, Weilei Mu, Wei Gao, Xiaoming Tao and Bao Yang. Funding was provided by North Carolina State University through the NC State Faculty Research & Professional Development Fund and the NC State Summer REU program.

 

Source:

North Carolina State University, Rong Yin, Laura Oleniacz

Photo Pixabay
10.01.2023

Fraunhofer: Optimized production of nonwoven masks

Producing infection control clothing requires a lot of energy and uses lots of material resources. Fraunhofer researchers have now developed a technology which helps to save materials and energy when producing nonwovens. A digital twin controls key manufacturing process parameters on the basis of mathematical modeling. As well as improving mask manufacturing, the ProQuIV solution can also be used to optimize the production parameters for other applications involving these versatile technical textiles, enabling manufacturers to respond flexibly to customer requests and changes in the market.

Producing infection control clothing requires a lot of energy and uses lots of material resources. Fraunhofer researchers have now developed a technology which helps to save materials and energy when producing nonwovens. A digital twin controls key manufacturing process parameters on the basis of mathematical modeling. As well as improving mask manufacturing, the ProQuIV solution can also be used to optimize the production parameters for other applications involving these versatile technical textiles, enabling manufacturers to respond flexibly to customer requests and changes in the market.

Nonwoven infection control masks were being used in their millions even before the COVID-19 pandemic and are regarded as simple mass-produced items. Nevertheless, the manufacturing process used to make them needs to meet strict requirements regarding precision and reliability. According to DIN (the German Institute for Standardization), the nonwoven in the mask must filter out at least 94 percent of the aerosols in the case of the FFP-2 mask and 99 percent in the case of the FFP-3 version. At the same time, the mask must let enough air through to ensure that the wearer can still breathe properly. Many manufacturers are looking for ways to optimize the manufacturing process. Furthermore, production needs to be made more flexible so that companies are able to process and deliver versatile nonwovens for a wide range of different applications and sectors.

ProQuIV, the solution developed by the Fraunhofer Institute for Industrial Mathematics ITWM in Kaiserslautern, fulfills both of these aims. The abbreviation “ProQuIV” stands for “Production and Quality Optimization of Nonwoven Infection Control Clothing” (Produktions- und Qualitätsoptimierung von Infektionsschutzkleidung aus Vliesstoffen). The basic idea is that manufacturing process parameters are characterized with regard to their impact on the uniformity of the nonwoven, and this impact is then linked to properties of the end product; for example, a protective mask. This model chain links all relevant parameters to an image analysis and creates a digital twin of the production process. The digital twin enables real-time monitoring and automatic control of nonwoven manufacturing and thus makes it possible to harness potential for optimization.

Dr. Ralf Kirsch, who works in the Flow and Material Simulation department and heads up the Filtration and Separation team, explains: “With ProQuIV, the manufacturers need less material overall, and they save energy. And the quality of the end product is guaranteed at all times.”

Nonwoven manufacturing with heat and air flow
Nonwovens for filtration applications are manufactured in what is known as the
meltblown process. This involves melting down plastics such as polypropylene and forcing them through nozzles so they come out in the form of threads referred to as filaments. The filaments are picked up on two sides by air flows which carry them forward almost at the speed of sound and swirl them around before depositing them on a collection belt. This makes the filaments even thinner: By the end of the process, their thickness is in the micrometer or even submicrometer range. They are then cooled, and binding agents are added in order to create the nonwoven. The more effectively the temperature, air speed and belt speed are coordinated with each other, the more uniform the distribution of the fibers at the end and therefore the more homogeneous the material will appear when examined under a transmitted light microscope. Lighter and darker areas can thereby be identified — this is referred to by experts as cloudiness. The Fraunhofer team has developed a method to measure a cloudiness index on the basis of image data. The light areas have a low fiber volume ratio, which means that they are less dense and have a lower filtration rate. Darker areas have a higher fiber volume and therefore a higher filtration rate. On the other hand, the higher air flow resistance in these areas means that they filter a smaller proportion of the air that is breathed in. A larger proportion of the air flows through the more open areas which have a less effective filtration effect.

Production process with real-time control
In the case of ProQuIV, the transmitted light images from the microscope are used to calibrate the models prior to use. The experts analyze the current condition of the textile sample and use this information to draw conclusions about how to optimize the system — for example, by increasing the temperature, reducing the belt speed or adjusting the strength of the air flows. “One of the key aims of our research project was to link central parameters such as filtration rate, flow resistance and cloudiness of a material with each other and to use this basis to generate a method which models all of the variables in the production process mathematically,” says Kirsch. The digital twin monitors and controls the ongoing production process in real time. If the system deviates slightly from where it should be — for example, if the temperature is too high — the settings are corrected automatically within seconds.

Fast and efficient manufacturing
“This means that it is not necessary to interrupt production, take material samples and readjust the machines. Once the models have been calibrated, the manufacturer can be confident that the nonwoven coming off the belt complies with the specifications and quality standards,” explains Kirsch. ProQuIV makes production much more efficient — there is less material waste, and the energy consumption is also reduced. Another advantage is that it allows manufacturers to develop new nonwoven-based products quickly — all they have to do is change the target specifications in the modeling and adjust the parameters. This enables production companies to respond flexibly to customer requests or market trends.

This might sound logical but can be quite complex when it comes to development. The way that the values for filtration performance and flow resistance increase, for example, is not linear at all, and they are not proportional to the fiber volume ratio either. This means that doubling the filament density does not result in double the filtration performance and flow resistance — the relationship between the parameters is much more complex than that. “This is precisely why the mathematical modeling is so important. It helps us to understand the complex relationship between the individual process parameters,” says ITWM researcher Kirsch. The researchers are able to draw on their extensive expertise in simulation and modeling for this work.

More applications are possible
The next step for the Fraunhofer team is to reduce the breathing resistance of the nonwovens for the wearer without impairing the protective effect. This is made possible by electrically charging the fibers and employing a principle similar to that of a feather duster. The electric charge causes the textile fabric to attract the tiniest of particles which could otherwise slip through the pores. For this purpose, the strength of the electrostatic charge is integrated into the modeling as a parameter.

The Fraunhofer researchers’ plans for the application of this method extend far beyond masks and air filters. Their technology is generally applicable to the production of nonwovens — for example, it can also be used in materials for the filtration of liquids. Furthermore, ProQuIV methods can be used to optimize the manufacture of nonwovens used in sound-insulating applications.

Source:

Fraunhofer Institute for Industrial Mathematics ITWM