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DITF: Biopolymers from bacteria protect technical textiles Photo: DITF
Charging a doctor blade with molten PHA using a hot-melt gun
23.02.2024

DITF: Biopolymers from bacteria protect technical textiles

Textiles for technical applications often derive their special function via the application of coatings. This way, textiles become, for example wind and water proof or more resistant to abrasion. Usually, petroleum-based substances such as polyacrylates or polyurethanes are used. However, these consume exhaustible resources and the materials can end up in the environment if handled improperly. Therefore, the German Institutes of Textile and Fiber Research Denkendorf (DITF) are researching materials from renewable sources that are recyclable and do not pollute the environment after use. Polymers that can be produced from bacteria are here of particular interest.

Textiles for technical applications often derive their special function via the application of coatings. This way, textiles become, for example wind and water proof or more resistant to abrasion. Usually, petroleum-based substances such as polyacrylates or polyurethanes are used. However, these consume exhaustible resources and the materials can end up in the environment if handled improperly. Therefore, the German Institutes of Textile and Fiber Research Denkendorf (DITF) are researching materials from renewable sources that are recyclable and do not pollute the environment after use. Polymers that can be produced from bacteria are here of particular interest.

These biopolymers have the advantage that they can be produced in anything from small laboratory reactors to large production plants. The most promising biopolymers include polysaccharides, polyamides from amino acids and polyesters such as polylactic acid or polyhydroxyalkanoates (PHAs), all of which are derived from renewable raw materials. PHAs is an umbrella term for a group of biotechnologically produced polyesters. The main difference between these polyesters is the number of carbon atoms in the repeat unit. To date, they have mainly been investigated for medical applications. As PHAs products are increasingly available on the market, coatings made from PHAs may also be increasingly used in technical applications in the future.

The bacteria from which the PHAs are obtained grow with the help of carbohydrates, fats and an increased CO2 concentration and light with suitable wavelength.

The properties of PHA can be adapted by varying the structure of the repeat unit. This makes polyhydroxyalkanoates a particularly interesting class of compounds for technical textile coatings, which has hardly been investigated to date. Due to their water-repellent properties, which stem from their molecular structure, and their stable structure, polyhydroxyalkanoates have great potential for the production of water-repellent, mechanically resilient textiles, such as those in demand in the automotive sector and for outdoor clothing.

The DITF have already carried out successful research work in this area. Coatings on cotton yarns and fabrics made of cotton, polyamide and polyester showed smooth and quite good adhesion. The PHA types for the coating were both procured on the open market and produced by the research partner Fraunhofer IGB. It was shown that the molten polymer can be applied to cotton yarns by extrusion through a coating nozzle. The molten polymer was successfully coated onto fabric using a doctor blade. The length of the molecular side chain of the PHA plays an important role in the properties of the coated textile. Although PHAs with medium-length side chains are better suited to achieving low stiffness and a good textile handle, their wash resistance is low. PHAs with short side chains are suitable for achieving high wash and abrasion resistance, but the textile handle is somewhat stiffer.

The team is currently investigating how the properties of PHAs can be changed in order to achieve the desired resistance and textile properties in equal measure. There are also plans to formulate aqueous formulations for yarn and textile finishing. This will allow much thinner coatings to be applied to textiles than is possible with molten PHAs.

Other DITF research teams are investigating whether PHAs are also suitable for the production of fibers and nonwovens.

Source:

Deutsche Institute für Textil- und Faserforschung (DITF)

Mobile robot system for automated loading of a bobbin creel (c) STFI
12.05.2022

STFI with sustainable and digital innovations at Techtextil 2022

The Saxon Textile Research Institute (STFI) will be presenting innovative highlights from research and development at Techtextil 2022, the international trade fair for technical textiles and nonwovens. In addition to a warp-knitted textile façade greening in a modular system and textile lightweight construction elements for the building sector made from hemp as a renewable raw material, the STFI will also be showing innovations from nonwovens research. The project optiformTEX is an example of the nonwovens competence: in this project, the mass per unit area was specifically influenced for the production of semi-finished products in the automotive sector. Furthermore, the Chemnitz Institute exhibits an ecological foam coating for protective textiles. Central highlight of the STFI's presence at the fair is also a mobile robot system, which demonstrates the automated loading of a small-scale bobbin creel.

The Saxon Textile Research Institute (STFI) will be presenting innovative highlights from research and development at Techtextil 2022, the international trade fair for technical textiles and nonwovens. In addition to a warp-knitted textile façade greening in a modular system and textile lightweight construction elements for the building sector made from hemp as a renewable raw material, the STFI will also be showing innovations from nonwovens research. The project optiformTEX is an example of the nonwovens competence: in this project, the mass per unit area was specifically influenced for the production of semi-finished products in the automotive sector. Furthermore, the Chemnitz Institute exhibits an ecological foam coating for protective textiles. Central highlight of the STFI's presence at the fair is also a mobile robot system, which demonstrates the automated loading of a small-scale bobbin creel.

Highlights at Techtextil 2022
The greened façade tile is a system with which large building surfaces can be cost-effectively greened through a simple, modular segment structure. In addition to insulating the building, the system has been created to meet the design requirements of a modern city centre; low-maintenance greening is made possible through functional integration in the textile carrier layer and coordinated plant selection.

Moulded components made of natural fibre nonwovens are increasingly used in the automotive sector. Conventional nonwovens currently have uniform masses per unit area. Technical solutions for load-oriented component reinforcement and the resulting optimised use of materials represent an enormous economic potential. The basic idea of “optiformTEX” was therefore to specifically influence the mass per unit area distribution in the pile before the semi-finished product is consolidated. As a result, a textile-technological process and the corresponding plant component were successfully developed.

Future-oriented materials are offered by developments from the field of renewable raw materials in combination with bio-based resin systems: In the “Gro-Coce” project, an innovative ceiling system was developed by combining sustainable building products and methods. Currently, a high-performance hemp-based semi-finished product as well as the steps for its reproducible production by means of textile surface formation is developed by the research team. Initial application and load tests of the hemp-based semi-finished products on wooden beams confirmed the high performance potential of the natural fibre materials.

Special functional textiles are based on composite materials with coatings or membranes. The previous production of the coatings/membranes poses ecological and health risks. At STFI, solvent-free, purely aqueous coating systems and a technology for their application were therefore developed for the protective textile sector, resulting in a breathable, waterproof and wash-resistant textile coating.

The central highlight of the STFI's presence at the fair is a mobile robot system, which demonstrates the automated loading of a small-scale bobbin creel. At the STFI, the robot is part of the “textile factory of the future”, where a play mat is woven and processed step by step along the textile chain.

The Montex®Coat ticks all the right boxes for coating success in 2021 (c) Monforts
A recent Montex®Coat installation at a European mill.
24.02.2021

The Montex®Coat ticks all the right boxes for coating success in 2021

Flexibility, product uniformity and automation are the keys to success for coating businesses in today’s rapidly-changing technical textiles industry, explained Jürgen Hanel, Monforts Head of Technical Textiles, at the recent 1st World Congress on Textile Coating.

Introducing the latest Montex®Coat magnetic roller coating option to virtual delegates from around the world at the conference organised by International Newsletters, Hanel explained why this technology makes perfect sense now

“The magnetic roller system allows a wide range of coatings and finishes to be carried out, while being easy to handle for operators and much easier to clean at the end of the process,” he said. “It provides textile finishers with an expanded range of options due to the fully-adjustable positioning of the magnet within the roller and with four different magnet positions possible, can be set to operate both as a direct coating system and as an indirect coater.”

Flexibility, product uniformity and automation are the keys to success for coating businesses in today’s rapidly-changing technical textiles industry, explained Jürgen Hanel, Monforts Head of Technical Textiles, at the recent 1st World Congress on Textile Coating.

Introducing the latest Montex®Coat magnetic roller coating option to virtual delegates from around the world at the conference organised by International Newsletters, Hanel explained why this technology makes perfect sense now

“The magnetic roller system allows a wide range of coatings and finishes to be carried out, while being easy to handle for operators and much easier to clean at the end of the process,” he said. “It provides textile finishers with an expanded range of options due to the fully-adjustable positioning of the magnet within the roller and with four different magnet positions possible, can be set to operate both as a direct coating system and as an indirect coater.”

With traditional dip coating systems, he added, as well as with many standard knife coating technologies, there is always a difference in the tension between the centre and the edges of the wide width fabrics being treated – and hence the amount of pressure with which the coating is applied. With the use of a magnetic roller, equal pressure is applied across the full width of the fabric, with consistent results even at wide widths of over 2.4 metres. In addition, adjusting the roller surface, rather than changing the coating formulation to match the required add-on and viscosity for each coating effect required, leads to much higher output from the line.

Cleaner and less wasteful
The contribution of such flexible and resource-saving new technologies to a cleaner and less wasteful textile industry was a key theme at the congress – held virtually across the four afternoons of February 11th, 12th, 18th and 19th – as was digitalization and the many advantages it is providing.

“A typical integrated Monforts coating line is automated from the inlet feed to the winder,” Hanel told delegates. “Adjustments can also be made simply and easily from the touchscreen and with the new hand-held remote controller which has recently been introduced for the Montex®Coat unit.”

Manual adjustment, he added, is time consuming and needs the attention of an experienced operator or the reproducibility will not be accurate between coating operations. The adjustment by motors allows each coating to be stored and downloaded again for 100% reproducibility.

The motors can be fully controlled from the touchscreen and all necessary adjustments carried out remotely, making switching from one process to another extremely quick and easy.
The accuracy that is now being demanded by today’s most exacting customers is met with an optional carbon fibre roller – especially in dealing with the winding tension required in the processing of materials such as prepregs for composites and other heavyweight fabrics. Typical applications for the Montex®Coat include the finishing of tents and awnings, black-out roller blinds and sail cloth, automotive interior fabrics and medical disposables. Full PVC coatings, pigment dyeing or minimal application surface and low penetration treatments can all be accommodated.

“The World Congress on Textile Coating was characterised by some very stimulating presentations and forums between the speakers and a global audience of textile specialists,” Jürgen Hanel concluded. “It truly reflected the high level of positive changes now taking place in not just textile coating, but the entire textile industry. I look forward to the next edition, which hopefully will be a face-to-face event for even deeper level discussions and debate.”

13.01.2021

The first online World Congress on Textile Coating

  • World Congress on Textile Coating, to take place on 11-12 & 18-19 February 2021.

The conference organisers have developed a well-structured programme of five sessions over four days with live discussion forums following each session for maximum attendee participation.

“The programme aims to be inspiring and informative, and will showcase the best innovations and collaborative actions in the industry. Functionality can be added to textiles and nonwovens at the beginning or the end of the supply chain, with an increasing range of raw materials, offering many options when designing and realizing a high-performance fabric. At the other end, there are many ways, such as applying a coating, to add functionality to an otherwise finished product. For example, the current pandemic has prompted new commercial anti-viral processes and four such presentations will outline the impact on industry and its response to the global pandemic,” says Dr Nick Butler, head of the conference organising committee.

  • World Congress on Textile Coating, to take place on 11-12 & 18-19 February 2021.

The conference organisers have developed a well-structured programme of five sessions over four days with live discussion forums following each session for maximum attendee participation.

“The programme aims to be inspiring and informative, and will showcase the best innovations and collaborative actions in the industry. Functionality can be added to textiles and nonwovens at the beginning or the end of the supply chain, with an increasing range of raw materials, offering many options when designing and realizing a high-performance fabric. At the other end, there are many ways, such as applying a coating, to add functionality to an otherwise finished product. For example, the current pandemic has prompted new commercial anti-viral processes and four such presentations will outline the impact on industry and its response to the global pandemic,” says Dr Nick Butler, head of the conference organising committee.

World Congress on Textile Coating will feature time dedicated to networking, encouraging attendees to interact with conference speakers and industry peers throughout the online programme, offering the opportunity to expand professional networks. All the presentations and discussion forums will be recorded for post-event viewing. Event sponsors imogo AB, Lamberti SpA, JX Nippon ANCI and Weitmann & Konrad GmbH & Co. KG will give individual presentations and host Q&A during the four days of the event.

For the full programme, speakers and abstracts please visit https://www.technical-textiles.online/WCTC.

Source:

AWOL Media