• Vulkanfiber1

Vulcanized fiber as a sustainable alternative to plastic

Vulcanized fiber is a traditional, proven and tested, but largely forgotten plastic precursor, that has been replaced from most of its earlier applications (suitcases, circuit boards in the electronics industry, flat backing materials) by the emerging mass distribution of plastics made from mineral oil since the mid-1950s.

Vulcanized fiber is made of renewable raw materials, for the most part from recycled cotton.

The cotton fibers that are used for vulcanized fiber incur as by-products, waste (used clothing collection) or discard from other production processes (clothing, cotton seed oil).
On top of that we try to use pulps made from sawdust, i.e. yet another by-product of other industrial processes (… cutting wood for the construction industry, wood pellet produktion or furniture industry, etc.). But wood pulp makes up only a minor proportion of our fiber mix.

With the impending entry into a sustainable circular economy, vulcanized fiber could become an interesting plastic alternative for environmentally conscious consumers.

The “mineral oil-free bio-composite material” vulcanized fiber is so low in pollutants that it was previously even used for artificial sausage casings. Due to its 100% biodegradability, you can throw it onto your home compost heap, as well.

1.     Vulcanized fiber as a sustainable upcycling product
Vulcanized fiber is a circular economy product that uses raw materials that otherwise would have been discarded. These raw materials experience a significant increase in value (upcycling) being processed into vulcanized fiber.

Vulcanized fiber results from merging and parchmentizing several layers of vulcanized fiber base paper. The raw material for vulcanized fiber base paper is technical cotton pulp (dissolving pulp made from cotton).

For this technical cotton pulp, we use cotton scrap from the cotton seed oil production (“linter”) and the textile production (“rags” = textile cuttings made of cotton). The rags accrue from pre- or post-consumer waste, i.e. as cut-offs from clothing production or as part of the used clothing collection.

In contrast to the also renewable wood pulp, the raw material for vulcanized fiber is not produced with the intention of using it for the production of vulcanized fiber base paper, it is a by-product.
The amount of cotton produced is determined by other markets, mainly that of the textile production. Only that part of the total cotton production which cannot be used for the textile industry (the short fibers near to the grain) is used as raw material for vulcanized fiber base papers.

A certain amount of cotton consumes for its production a certain amount of ressources. And it doesn’t matter if someone uses the by-products of the cotton production or simply wastes them. If the vulcanized fiber would disappear tomorrow from the market, this would happen without any impact onto the total amount of cotton being produced worldwide. I.e., there is no primary consumption of ressources (water, chemicals, energy, soil, fertilizer etc.) for the raw material of the vulcanized fiber: the consumption of these ressources is linked to other uses (see above).
For comparison:
If you want to achieve the same sustainability with normal paper as with vulcanized fiber base paper, the wood pulp required must be made solely by sawdust, which had occurred when cutting wood for other processes such as the construction-, wood pellet- or furniture industry.

2.     Linters as raw material for vulcanized fiber
After harvesting, the cotton fibers are cleaned from undesirable components, i.e. the long cotton fibers are separated from the short fibers close to the grain. The good (long) fibers go into the production of textiles . The short fibers close to the grain go into the cotton seed oil production.

This is the first stage of cotton waste (… or: by-product) recycling.

This “waste” is an untreated, fresh by-product that stems from the production of cotton for manufacturing textiles. This by-product would not exist on its own, i.e. you would not plant cotton to produce cotton seed oil.

The fibers that remain after pressing the seeds in the oil mills serve as a raw material for vulcanized fiber.

This is the second stage of recycling cotton waste: this is where the waste of the waste (… the “by-product”) is exploited – and that with an increase in value!

3.     Rags as a raw material for vulcanized fiber
In the past (till the middle of the 19th century) paper was made from rags.

With the strongly increasing paper consumption during the second half of the 19th century, the supply of rags was no longer sufficient, new raw material sources had to be developed for the paper industry and the modern wood based mechanical and chemical pulp production was invented.

For the sake of simplicity, Cordier Spezialpapier GmbH uses rags from pre-consumer cut-offs, i.e. waste that arises when cutting during clothing production. Using rags from the used clothing collection would also be possible.

4.     The process of vulcanized fiber production
 a.       A pulp mill produces cotton pulp from linter (CLP = cotton linter pulp) or rags (CRP = cotton rag pulp).

The processes are …

–           shredding & singularizing the fibers (rag pulp process)
–           digesting (setting the correct viscosity, decolouring)
–           cleaning & sorting the fibers
–           refining (=milling) the fibers
–           bleaching (with peroxide)
–           dewatering and bale pressing

b.      A paper mill produces cotton paper (VFBP = vulcanized fiber base paper) from the cotton pulp.

c.      The VF-Factory produces vulcanized fiber based on the VFBP delivered by the paper mill.

          For that matter, several layers of paper are connected by a parchmentizing process:

See also the website of Dynos GmbH: production of vulcanized fiber

This process is forming a web-type material with a thickness of approx. 1 mm.

Through further process steps, a wide variety of products (including those of greater height/thickness) can be manufactured from this basic shape.

See also … Bio-sourced material (Source: Wirtschaftszeitung AKTIV Chemistry No. 5, from July 13, 2019, page 3.)

5.     The use of vulcanized fiber
The currently most important applications for vulcanized fiber are grinding disks and the small red sealing rings used in water pipes which are still common in German speaking markets.

Vulcanized fiber used to be a very common, widely used material, which has the following properties important for consumers:

–           high rigidity at a low weight
–           good sliding properties
–           a visually pleasant structure
–           a pleasant (surface) feel (feels warm)
–           good insulation properties
–           spark extinguishing properties

Typical applications were deep-drawn molded parts of all kinds, e.g. …

–           suitcases
              –           in the first half of the 20th century, vulcanized fiber was the standard material for suitcases.                     
              –           the material is still represented in the luxury segment of the suitcase market
–           components for the furniture industry
              –           e.g. slide rails for drawers
–           surface coatings for panels and furniture surfaces
–           load-bearing parts
–           insulating material (printed circuit boards, circuit boards in the electrical industry)
–           welding masks
–           decorative objects
–           packagings
–           etc.

You can find possible VF-applications – available here – and examples for the converting of VF – here – e.g in the brochures created by one of our customers.

                                                                            Fig. 1: Vulcanized fiber as packaging material

                                                                            Fig. 2: Vulcanized fiber for the furniture industry

Nowadays, vulcanized fiber could regain a wide range of uses in the new context of sustainability.

Certain applications that are currently met by plastic products cannot be replaced by an application of vulcanized fiber. Anyhow, one could find many applications for the use of vulcanized fibers: Its potential is sufficient to give the material a strong second life.

Additionally, the material as such does not need to be developed, it already exists.

However, the respective applications would have to be developed. To do this, one has to refresh skills and knowledge and adapt existing systems.

Here are some examples of previous or technically possible new applications:

                                                 Fig. 3: Frames of a pair of eyeglasses made from vulcanized fiber

                                                 Fig. 4: Deep-drawn case shell

Other examples of use

Other finishings for functions such as thermal insulation, moisture protection, etc. would open up new options.

Manufacturers of vulcanized fiber are:

DYNOS GmbH:                                          https://www.dynos-gmbh.de/1/commercial-market/forms-of-delivery
Ernst Krüger GmbH & Co. KG:    https://www.hornex.de/html/englisch.html
Sachsenröder GmbH & Co. KG:    https://sachsenroeder.com/en/vulcanized_fibre_savutec/what-is-vulcanized-fibre-savutec

You would have to contact these companies if you wanted to develop an application from vulcanized fiber.

6.     Links on the subject “vulcanized fiber”
(…all content in German)

YouTube videos


Other links…


7.     Vulcanized fiber and research
For example, in recent years the technical university TU Dortmund University (Department of Machine Elements, Prof. Dr.-Ing. Bernd Künne & Dipl-Ing. D. Dumke) engaged itself with the topic of vulcanized fiber in more detail.

This resulted in some interesting publications, e.g. “Direction-dependent mechanical characterization of cellulosebased composite vulcanized fiber”