TITK: Sustainable textile fibers for clothing...

Sustainable textile fibers for clothing, lightweight construction and greening

At the TITK a process to directly dissolve and dry-wet form cellulose has been established – the Alceru-process (left). Based on this process, to date functional lyocell fibers have been developed. The latest modification (right): By loading with copper ions the fiber Cell Solution Bioactive has a permanently anti-viral effect. (Source: TITK)
At the TITK a process to directly dissolve and dry-wet form cellulose has been established – the Alceru-process (left). Based on this process, to date functional lyocell fibers have been developed. The latest modification (right): By loading with copper ions the fiber Cell Solution Bioactive has a permanently anti-viral effect. (Source: TITK)

Textile processing of hemp pulp, biodegradable planting bags at buildings and natural fibers for automobile interiors can make an important contribution to climate protection and CO2 savings.

Worldwide the capacity of cotton production is reaching its limits due to its high land and water usage as well as the necessary use of pesticides. Need of textile fibers, however, is increasing – particularly in view of rapid population growth in Asian countries. This mismatch strongly speeds up demand for sustainable cellulose regenerated fibers (man-made cellulosic fibers – MMCF). Cellulose as natural, constantly renewable raw material can be used in innumerable fields. The Thuringian Institute for Textile and Plastics Research (TITK), Rudolstadt/Germany, as a leading development center for environmentally friendly and sustainable cellulose forming, has established a modified lyocell process to incorporate additional functions into the lyocell fibers.

For these fibers pulp from natural sources (spruce, beech etc.) or – as part of circular economy – recycled old textiles can be used. In addition to that, lyocell is biodegradable. Compared with other cellulose regenerated fibers like viscose the production process is regarded as especially environmentally friendly. Thanks to a patented process, the TITK is able to provide the lyocell fibers with diverse additional functions – for example with thermo-regulating or skin-caring properties or also with electrical conductivity. Another modification of this fiber underwent a veritable demand kick during the corona pandemic: the cellulose fiber with silver ions (brand name Cell Solution Bioactive). It has an antibacterial and fungicidal effect – therefore, kills germs and fungi very reliably. During the last months, that fiber was further developed: Is Cell Solution Bioactive equipped with copper ions, the fiber has a permanently anti-viral effect both against non-enveloped and enveloped viruses like influenza or Covid-19.

As it has become apparent in the meantime that wood as sole raw material provider for MMCF is becoming less attractive, plant fibers from direct cultivation or from agricultural residue are gaining increasing market shares. The TITK oriented towards this trend together with its subsidiary smartpolymer GmbH, Rudolstadt/Germany, and developed a procedure to generate hemp-based lyocell fibers under the brand name Lyohemp. Thus, pure hemp pulp is processed to high-quality textile staple fibers which even offer very good wear-physiological properties. For Lyohemp, controlled organically grown hemp for medicinal application can be utilized, for example. To date, only the upper third of the plant – flowers and seed heads – have been used, but now the complete stems can be exploited. Thereby, the institute builds upon a cellulose which arises anyway in passing – without additional land or water usage. This means that previous agricultural residue is now usable for environmentally friendly and sustainably produced clothing textiles.
A challenge and at the same time a chance is to establish local, textile value-added chains in Germany and Europe. These can contribute to a sustainable, independent, and local textile industry. Currently, the corresponding regional value-added chains with a production volume of several tons are being established and evaluated with the participation of the TITK.

Lyocell fibers also played a decisive role in another very promising research project: UrbInTex – Green City. In this joint research project, several enterprises and business-related research institutions are looking for intelligent, textile-based solutions for the city of the future. One idea is an innovative planting system being able to provide for more green areas downtown, especially in vertical application scenarios. The task of the TITK was to develop innovative cellulosic regenerated fibers which can be processed as textiles as well as nonwovens which are characterized by a significantly higher absorptive and water retention capacity. Planting systems could be realized with lightweight, sustainable textile materials which can be adapted through modular construction and easy adaptability to most various building structures.
First larger fiber and nonwovens samples could be tested by project partners and be further processed, such as for the production of sample fabrics with planting bags in combination with wool. In the end, different textile components were available (e.g. fibers, bag fabrics, braided strings for seed uptake, soutage embroidery) which offer new solutions for vertical greening.

The TITK is also very active in the field of lightweight applications with technical textiles and has been researching materials and procedures for textile reinforced semi-finished products and fiber reinforced composites. Sustainability, resource efficiency and CO2-minimization have played a decisive role here long since. By focusing on a material cycle as closed as possible, cost-effective recycling processes and reuse of high-quality materials are the aim of every new development.
Therefore, the transfer of the exploitation of carbon fiber production residue to industrial scale was an important task at the TITK. The institute developed a procedure for reprocessing the dry waste, i.e. the offcuts occurring in the handling process. Thereby, the opened fibers are used in different processes to produce nonwovens. Therefore, a high-quality residue gains new utilization potential – resource efficiency and productivity are increased.

With the production of trim parts for the automobile interior the TITK showed that sustainable materials do not necessarily entail losses in design and comfort. Visible natural fibers and compression elastic components have been difficult to combine in appealing form. Therefore, during the research project natural fiber-interior-components with soft-touch-surfaces processes and approaches were examined to replace critical materials in door panels, dashboards and other parts by natural fiber-based nonwovens as soft touch elements. All that in combination with the same or even reduced weight and adherence to all mechanical requirements. Further conditions were the use of existing plant technology as well as the fulfillment of the high requirements regarding fastness to light and surface resistance through the application of PP foils suitable for the use in automobiles.

ALCERU, Cell Solution, Lyohemp = registered trademarks

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