The few cancellations by the presenters did not prevent the first conference on cellulosic fibers in Cologne during the second week of February. Cellulose is one of the most widely occurring fibrous materials in organic nature, and although ingenious straight-chain polymer has been studied for nearly 200 years, new perspectives are constantly opening up. The themes of the conference were new technologies and applications, market conditions, sustainable development, strategies and societal issues. (Carus)
The annual growth rate of regenerated cellulosic fibre (6.1 million tonnes) is projected to be nearly 5% until 2024. This is mainly due to the conversion of paper mill production into dissolving pulp and an increase in fibre mill capacity of EUR 9 million tonnes per year. On the other hand, the production capacity of dissolving pulp (DWP) already exceeds 10 million tons. At the same time, it seeks to meet the challenges of sustainable development, such as Canopy and other far-reaching certification programs. Due to the long textile processing chain, extensive co-operation is required from brand owners through technology to legislation. (Landsdell, Rycroft, Canton)
Raw materials
In addition to wood, paper pulp that was not recycled was also used as a raw material, amounting to some EUR 20 million tonnes in Europe and wheat straw from cereals. A pilot plant for 1000 tonnes of straw per year has been set up in Denmark for technology, possibly leading to a plant of 40000 tonnes. A Lyohemp pilot plant of 1000 tonnes/a has been set up in China, using raw straw from the cultivation of medicinal hemp. The method uses alkali-peroxide bleaching and enzyme treatments followed by dissolving the cellulose in a NMMO / water solvent. Infite Fiber introduced a cellulosic carbamate process for using cotton textile waste (jeans) as a raw material for new fibres. The Once More project is under way at the Södra pulp mill, where pulp from cotton and viscose waste is added to the dissolving pulp. Lenzing also uses fiber treated with cotton latex bricks in Refibra technology to manufacture Lyocell fibers. (Pijman, Bonefeld, Meister, Alava, Glaesson, Schuster)
Micro plastics in Oceans
As the source of marine micro-plastics, PET is by far the largest due to its widespread use in garments that are washed dozens of times during its lifetime. PET products researched at the University of Lower Rhine lost 2.5-3.0 g / kg in weight, equivalent to globally more than 125,000 t of non-degradable microplastics. In contrast, viscose fibers – also dyed – will degrade within weeks if the fiber surface has not been treated with a synthetic polymer. In San Diego, California, materials are tested under natural conditions in seawater tests. In this case, first the biomechanical structure of the fiber undergoes a change, after which smaller fractions decompose into CO2 and water. The degradation was compared to that of the deciduous leaf cellulosic fibers. (Rabe, Deheyn)
Research and development
In addition to Lenzing Refibra, news of viscose product development was heard on products from Kelheim and Aditya Birla. Kelheim is certified in the FSC system for the origin of wood and the principles of ecologically, socially and economically sustainable forestry in the PEFC network. This also applies to triangular and flat fibers used in wet wipes. New products include linen towels made of a mixture of viscose short fiber and pulp, as well as antimicrobial quat fibers. Viscose silica (Visil) fibers can be made when needed, but price competition in the Far East is often too fierce. Aditya Birlan R&D has developed a range of spun dyed viscose fibers. Colour shades and colour fastnesses are very good in textile products and the customer does not have to clean dye water when using fibers. (Scholz, Sharma)
New Methods and Chemicals
New regeneration methods for lyocell were presented at Metsä Spring’s Ioncell pilot plant in Äänekoski. It has a capacity of 5000 t / a and Itochu, a co-operating company in Japan, produces fiber textiles for trial marketing. In addition, the poster booth provided access to the Biocelsol method, an enzyme-based method that does not use any organic solvent, which was further developed in the EU Neocell project. (Suurnäkki, Vehviläinen)
Chemicals for cellulose processing are developed on the basis of vegetable oil and in waste water to produce the lowest chemical oxygen demand (COD). Functionality is difficult to maintain with a COD of 0, but the goal is minimal, for example Bluesign or Roadmap Zero. New spinning and avocating agents for the viscose and lyocell process have also been developed on a plant-based basis. Nanocellulose can also be made from cotton waste by the TEMPO method. It can be utilized by improving the strength through the orientation of the films and fibers. The improvement of dyeing yield has been studied using dyed nanocellulose as a dye. (Pellegrini, Wendler, Nyhofen, Ankeny, Håkanson)
From certification of paper to fibers, textiles and fashion brands, Canopy caters for certification (FSC) customers in the forest sector. In addition to it and PEFC, fiber and textile products are certified by the International Sustainable Carbon Certification (ISCC) index, which emphasizes durability and transparency. Of particular important is information on sustainable forestry and greenhouse gas (GHG) production or product data. (Rycroft, Kroll)