DEVELOPMENT SPINNING TECHNOLOGIES FOR SUSTAINABLE TEXTILE PRODUCTS BASED ON A RESEARCH 4.0 MODULAR PLATFORM APPROACH
Keywords: Industry 4.0, Research 4.0, Sustainable textiles. Recycling, Biobased
The global demand of textile fibres has been almost doubled from approx. 60 to 110 million tonnes per year from 2000 to 2020 while the number of produced garments increased three times from approx. 50 billion to 150 billion. There are projections showing an increase in consumption reaching almost 150 million tonnes by 2030. With cotton stagnating at 20-25 million tonnes, the main contribution to this growth is provided by man-made fibres like polyester. In the same period, world’s population has increased by approx. 30% to reach almost 7.8 billion people.[1] The mismatch between both growth rates reflects an imbalance leading to the unsustainable situation which we are currently facing.
In 2015 only 1% of textile products were recycled at a global level as the result of the big challenges that the textile industry is facing in order to reach circularity.[2] The factors are manifold: undesired substances which are embedded in the yarns and cannot be recycled, the fact that many garments are made of mixed materials which are hard to separate, recycling costs being higher than the value of virgin materials, etc.
Technical textiles refer to textile materials primarily used for their technical performance and functional properties. They make roughly 35% of the total production of fibres worldwide. [3] The global yearly consumption of technical textiles was approximately 42 million tonnes in 2021 and is expected to reach not less than 67 million tonnes by 2032, thus experiencing an increase of roughly 60%. In monetary terms the technical textile market is estimated to reach 43% of global textile sales by 2032 [4], so that the size of this market size is projected to grow from $164.6 billion in 2020 to $222.4 billion by 2025, i.e., at a CAGR of 6.2% [5].
Given the anticipated rapid increase in demand for textile fibres in the years to come, it is crucial to implement transformative sustainable consumption and production models and circular business technologies both in the garment and technical textile industries.
The Ellen MacArthur Foundation defines recycling as the last value cycle after other measures (inner value cycles) to restore and regenerate value with the lowest environmental impact possible [2]:
- Maintain / Repair
- Re-use as a product
- Re-use as a material
- Recycle
Users represent the keystone for closed loops based on their behaviour towards usage, maintenance and repair of textile products expanding their lives to the maximum possible.
Technical textiles are commonly not feasible for re-use as they usually reach their end-of-life status based on damage rather than based on fashion as it is the case for garments. Re-use of textiles can be done as products (preferred option) or as textile material. When the quality of the fabric is such that it is no longer suitable for re-use as a product or material, it should be recycled.
There are mainly four main recycling technologies defining the industrial processing of new fabrics [6]:
- Mechanical recycling resulting in fibres as the raw textile material is broken down in separate fibres which can be re-produced into new textile structures.
- Chemical recycling of cellulose-based textile products (e.g. cotton, viscose, etc.) which are dissolved and spun into new fibres.
- Thermo-mechanical recycling of synthetic polymers, where polymers are melted and chemically improved (if required) before being spun again.
- Chemical recycling of synthetic polymers that are broken down to their monomers. Monomers can be polymerised again into the original polymers.
According to the EU Strategy for Sustainable and Circular Textiles, long-lived and recyclable textile products will be placed in European markets. These products will be made of recycled fibres to a great extent and free of hazardous components. The vision of the European Commission is a thriving ecosystem for circular textiles supported by sufficient capacities for fibre-to-fibre recycling and feasible services for re-use and repair. [7]
As consumers are nowadays searching for more sustainable solutions that address key environmental issues related to the garments they wear, there is a growing trend towards sustainability in the textile industry at global level. This new situation is building up pressure on textile brands by holding them accountable for their environmental impact in a way that consumers expect meaningful social and environmental goals and a trustworthy implementation of a sustainable product stewardship. This paradigm shift involves both the implementation of recycling approaches for textile yarns (both synthetic and biobased) and a growing use of biobased materials like MMCFs (Man-Made Cellulosic Fibres) as an alternative to synthetic fibres. MMCFs, also known as regenerated cellulose fibres, are a group of fibres that are conventionally derived from wood, whereas other sources of cellulose are gaining importance nowadays (e.g., alternative plant resources, recycled agricultural waste, etc.).
Textile industry is adapting to this new situation and manifold actions are being taken. Mainly there are two major trends:
- Recycling of used textiles products following any of the already mentioned recycling technologies.
- Production of bio-based fibre yarns.
Cellulosic (bio-based) and recycled fibre products pose a big technological challenge as growing demands on the varying quality of feedstock and the achievement of a consistent fibre performance require a continuous development and optimisation of both technology and production parameters.
Research work in this field is thus characterised by a high degree of adaptation needs. Research facilities must be able to be adapted after initial experiments and the knowledge gained thereby. The necessary adjustments are made under the conditions of a highly complex manufacturing process, which is determined by many influencing parameters. This results in the following requirements for the flexibility of the electronics control of the research facilities:
- INTEGRATION: Easy integration of new production modules.
- SCALABILITY: Easy replacement of production modules with modified specifications.
- LEXIBILITY: Easy modification of production steps’ positioning within the production line.
- HIGH PERFORMACE: Intelligent production modules synchronised by a master process control level.
- ANALYTICS: Continuous monitoring and evaluation of process parameters.
Research 4.0 is to be understood as the implementation of the principles of Industry 4.0 to research facilities. VDMA has developed a toolbox in which the stages of development represent the path to the realisation of an Industry 4.0 solution. [9]
DIENES’s implementation of Research 4.0 approach is called MultiMode®. In a MultiMode® plant, each process step is represented by a module which can be individually adapted to customer-specific requirements and has its own decentralised control. Thus, a modular production line consists of several intelligent units which can be easily exchanged and rearranged at any time with a reduced programming effort. Moreover, all production parameters can be permanently visualised and recorded, enabling a complete traceability of the process.
The configuration of a Multimode® system follows a hierarchical structure running at three levels: Slave (Level 1 – MMS: MultiMode® Slave), Master (Level 2 – MMM: MultiMode® Master) and Upper control (Level 3 – MME: MultiMode® Explorer).
Every single yarn treatment module represents a production step and can store knowledge at module level and act according to the function of the module in interaction with other modules. Each of these modules is equipped with a MultiMode® switch and control cabinet, hence it is equipped with its own intelligence based on a PLC to control itself and to organise the module in association with other modules in the plant. The control hierarchy has an intelligent modular structure that configures itself according to the arrangement of modules given by the hardware and the interfaces within the system. Thus, a structure is realised that allows new arrangements by configuration and without any programming work required.
From a control perspective, the process level with the MultiMode® boxes forms the control level “BASIC” with the MMS modules. The second control level “INTEGRATED” is organised by the MMM, which is also responsible for configuring and forwarding the information to the computer-based MME. The computer level control (MME) is the process control level “ADVANCED” and organises the elegance functions of the system like, e.g., real-time evaluation of sensors, data logging with a connection to an SQL database every second, tracking of operator inputs, transfer of data to Excel for further evaluation, alarm logging, recipe management for saving current settings as a recipe under a freely assignable name to be used a later moment if necessary, etc.
REFERENCES
[1] Cordeiro et al.; Becoming mainstream: Future opportunities and challenges for novel textile; International Conference on Cellulose Fibres, Cologne, 2022 [2] Ellen MacArthur Foundation; A new textiles economy: Redesigning fashion’s future, 2017 [3] Market demand of technical textiles worldwide in 2014 and 2022 (in million tons). In Statista – The Statistics Portal, available at https://www.statista.com/statistics/741532/technical-textiles-global-market-demand/ (accessed on March 13th 2023) [4] Fact.MR (February 2022). Technical Textile Market.https://www.factmr.com/report/technical-textile-market (accessed on March 3rd 2023) [5] Markets and Markets (2021). Market Research Report (February 2021). https://www.marketsandmarkets.com/PressReleases/technical-textile.asp (accessed on March 3rd 2023). [6] Fontell, P., Heikkilä, P.; Model of circular business ecosystem for textiles, VTT Technical Research Centre of Finland Ltd, November 2017 [7] European Union Strategy for Sustainable and Circular Texiles. European Commision, February 23rd 2022, https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A52022DC0141 (accesed April 14th 2023) [8] European Commission; European Directive 2008/98/EC on Waste; Official Journal of the European Union L312/3, 2008 [9] Stahl, Beate; et al; Leitfaden Industrie 4.0 Orientierungshilfe zur Einführung in den Mittel-stand; VDMA Forum Industrie 4.0; VDMA Verlag ISBN 978-3-8163-0677-1; 2015
