Reclaimed fibres

Guhch, B., 2006b. Development of products made of reclaimed fibres. In Wang, Y. (Ed.), Recychng in Textiles. Woodhead, London, pp. 117—136. 

Reclaimed fibres mixed together are one example of how multi-material composite systems can be used. Compacting as in the recycling of plastic materials is another one. The agglomerate achieved this way, however, faces problems with regard to marketing. 

Upholstered furniture contains textile nonwovens with a variety of degrees of bonding. They are also found as textile cover material. Nonwovens used in areas well below the surface are made from reclaimed fibres. They are of little interest with regard to recycling. However, the voluminous cover nonwovens used directly between the core of foam and the surface cover material are certainly of interest. Generally, these are made from white primary fibres. Made into reclaimed fibres, such materials can well be re-used to make nonwovens. The main prerequisite to... 

Currently, raw materials available from reclaimed fibres have short fibre lengths but it is hard to clearly define their other characteristics. We should aim to break down the waste in question so as to achieve a type of reclaimed fibre which, with regard to its further application, is easy to characterize. In particular, we should aim to preserve fibre length as much as possible for most final applications. 

Producers use reclaimed fibres for a number of reasons They are low cost. Sometimes, chemical fibres are not available. Raw materials and waste disposal are becoming more and more expensive. Ecological aspects, too, play an ever more important role. It is in this context that, looking for suitable raw materials to make reclaimed fibres, household textile waste as well as industrial waste should receive more attention. 

Breaking-down equipment should only be used to process waste which, in the end, can be made into reclaimed fibres. 

The degree of material break-down is descriptive of the spectrum of materials that results from the breaking-down process. It is defined as the proportions of fibres, threads, bits and remains of fabric in a specimen of 3 g or 10 g of the blend of reclaimed fibres, depending on the proportion of unopened pieces (by manual separation), in nnits of mass per cent. 

In addition, both producers and users of reclaimed fibres should know the material composition of the blend of reclaimed fibres in question. It can be defined by means of qnantitative chemical analysis, which, however, will entail corresponding cost. There are systems allowing quick definition which are based on near-infrared-spectroscopy. They are limited to qualitative information of the fibre materials contained in a blend. One well-known example is the sorting of end-of-life carpets by the kinds of polymers contained in their piles. - ... 

Reclaimed fibres can be manufactured from a variety of textile waste. Both quality and processability of such fibres depend on the kind of waste. Well-known are the pure sorted fibres of high-quality which are achieved from spinning-fibre waste. In contrast, reclaimed fibres made from end-of-life textiles are of much poorer quality. They will rarely be found of homogeneons fibre type. 

There are many ways open to using reclaimed fibres in both textile and nontextile products. The suitability of processes depends on waste characteristics and on how much they cost. 

To achieve easy processabihty, reclaimed fibres are frequently blended with primary fibres (about 15%). 

As compared with the production of yams, reclaimed fibres are even more often used today to make nonwovens. In Germany, about 95% of the reclaimed fibres produced are processed into nonwovens. The main fields of application are in technical textiles, which we will take a look at in the paragraphs to follow. 

Technical textiles as a market for products made from reclaimed fibres... 

Prerequisites to using reclaimed fibres to make technical textiles... 

It is most important to have reclaimed fibres available which are of the right quality with regard to the purpose and which are cheaper than primary fibres. Quality is expected, throughout the whole production period, to constantly remain within the parameters defined. Such parameters can, and should, be documented. 

Producers of reclaimed fibres being suppliers of raw materials, they should provide a range of, say, ten to thirty types of reclaimed fibre. With each of these, they should clearly define parameters with regard to their possible uses and the products they may serve, such as... 

After-treatment should focus on the further enhancement of the quality parameters reached in the breaking-down process, so that the reclaimed fibres become more competitive. The steps to be taken include... 

Seen with the user s eyes, unproved quality of reclaimed fibres means... 

At the point of the producer of reclaimed fibres handing the materials over to the user, it is helpful to have a syslan of quality assessment available that allows the documentation of the technological parameters of the material. It will oeate the base on which contracts can be negotiated and questions of warranty clarified between the producer and the user. Such a system should help to define the parameters below within a short time and at low-cost ... 

Depending on product functions, reclaimed fibres can be looked upon as conventional in technical textiles, particularly in nonwovens (mobility textiles which mainly serve to cover up surfaces or to insulate materials, agrotextiles, and geotextiles which are used to protect soil against erosion). In all these cases, reclaimed fibres are used because of low prices, or because they merely cover something up. However, reclaimed fibres are also applied in nonwovens to utihze highly valuable functional components. This concerns fibres which would not be available at a competitive price if made from primary materials, such as... 

Geotextiles may be looked upon as an ideal field for the application of reclaimed fibres. To make them, it is important to use well-selected textile waste and to exactly tune the process parameters when breaking it up. In this way the quality requirements below can be met ... 

Standards vary from country to country. European Standard EN 13249, for instance, prohibits the use of reclaimed fibres from end-of-life textile waste. Otherwise, reclaimed fibres of industrial waste need to meet the strengths required by the purpose or else must not be used. Table 9.2 shows further fields of application of reclaimed fibres in technical textiles. 

Table 9.1 Needle-punched nonwoven of primary and reclaimed fibres Comparison of hydraulic parameters...

Application Most urgent requirement to be met by reclaimed fibre ... 

As can be seen in Table 9.3, both the aerodynamic and mechanical processes of web formation raise different questions with regard to the quality of reclaimed fibres. When producing the fibres, quality parameters can be set to some degree. 

Needle-punched warp-knitted nonwoven material serves us as a further example of how important the quality of reclaimed fibres is. This material is used to substitute for the components of polyurethane foam in laminated composites. The purely textile composite resulting allows one to recycle both the production waste generated and the composite structure itself at the end of its life (see Chapter 3). To make sure a nonwoven containing 40% of reclaimed fibres can be well processed on a warp-knitting machine and shows full functionality when used as a laminated composite for a motor vehicle seat, the reclaimed fibre used needs to meet the following requirements ... 

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