Getting to know your fibres - Part 3 - Unusual Fibres. 

Ok, so if you've been following along for the last few weeks, you'll know that we've already covered Animal Fibres and Plant Fibres (concentrating on cellulose fibres). This week it's the turn of unusual fibres - these ones don't easily fit into either of these categories, and are often considered semi-synthetic. 

So lets get started with something that you might not consider to be able to actually be a fibre...

Milk Fibre 

Yep, you read that right. Milk. You're right in thinking that generally milk is not known for being particularly fibrous. So how does it work? It was first invented in Italy at the start of 1935 and did originally involve a lot of chemical processes. It is considered a semi-synthetic fibre because of this, but modern production methods have stepped away from harsh chemicals and moved towards eco friendly processing. 

The Production

The two main modern manufacturers are QMilk in Germany and Duedilatte in Italy. Although their exact processes are secret, the general idea is that milk waste which is not fit for human consumption and due to be disposed of is instead repurposed, rather than any milk being specifically produced for the fibre. The part of the milk which is extracted is the protein, called Casein. This is where the production starts to vary between the two companies:

Qmilk

The Casein protein is converted into a powder form, where it is then mixed with water to create a dough. The dough is then heated and natural additives, including zinc and beeswax are added to improve the fibre. This mixture is then extruded through a thin nozzle into fibres. The resulting fibre can be composted at home, contains no plastics, and is soft and eco friendly. This fibre is as close to being 100% milk protein as you can get. 

Duedilatte

The Casein protein is converted into a powder form, and then dissolved into a 'viscose-based spinning solution'.

A Viscose spinning solution is used in the manufacture of a few of our unusual fibres, so I'm going to explain it to you now. A viscose-based spinning solution is created by dissolving plant cellulose (usually wood or bamboo) in caustic soda, which is then further treated with and carbon disulfide. This process creates something called Sodium Cellulose Xanthate. This is then dissolved further in more caustic soda until it looks like a syrup. 

The Casein is mixed with this viscose spinning solution, which is then 'wet spun'. This means that it is pushed at pressure through a device called a spinnerette, with many tiny holes in it, Contrary to the name, the spinnerette DOES NOT SPIN. As the fibre moves through the spinnerette, it goes through an acid bath, which causes the protein and cellulose to solidify once more. The resulting fibre is therefore technically 'milk infused viscose' rather than pure milk fibre. It is still 100% compostable, but it is important to understand the distinctions between these two production methods. 

The conclusion

For me, I feel that the Qmilk process is a cleaner one, however I haven't (as yet) been able to see the two fibres beside each other and do a comparison for spinning or using the resulting product. 

I have spun with 'milk protein fibre', however I don't know which method this will have been made with, and I haven't been able to see where suppliers such as World of Wool source theirs from to get any closer to an answer. 

What I can tell you is that the fibre is really soft and silky, and it's very nice to work with! Both main manufacturers strive to be as eco friendly as possible, so the upshot is that you're likely to have a sustainable product created from waste wherever you happen to purchase it. 

Rayon/Viscose

Viscose or Rayon is a semi-synthetic fibre, usually made from wood, bamboo, or other cellulose plant fibres such as cotton. 

Production

I covered some of this above in the Milk Fibre section, so I won't re-do things! The start of making viscose or rayon begins with pulping the material. Wood chips or other agricultural plant waste is put into a blender with water until it turns into a pulp. This pulp is then soaked in a strong alkaline solution to remove impurities and leave the cellulose structure intact. 

The resulting pulp is then rinsed repeatedly to remove the remaining alkalinity.

Once rinsing has taken place, you then need to dilute the cellulose further and drain it through a fine mesh. This means that the water can escape, whilst the fibres cling together over the top of the mesh to form a sheet. This sheet is then passed through rollers to remove any remaining moisture and force the fibres into a closer-knit sheet. 

This sheet is then what is used to create the 'viscose solution' mentioned in the steps above. and the process works as the Duedilatte process above to create fibres, only without adding in any milk protein. 

As a fibre or yarn.

As a fibre, viscose/Rayon is thought to be nice and breathable, and depending on how it is produced can be very environmentally friendly. Garments made from viscose tend to have a nice drape and feel cool, they are also very absorbent (even more than cotton!) so it will keep you dry if you get hot, but it's also best not to go out in the rain in them, and allow extra time for them to dry when you wash them. 

Tencel/Lyocell

Although very similar in construction to viscose, Tencel/Lyocell are made using more environmentally friendly processes. Tencel is the premium brand name, and Lyocell is the fibre. although often the names seem to be interchangeable in the world, some Lyocell is not made by the Tencel company. I am going to talk through the processes of the Tencel factory, as although other brands of Lyocell are available, Tencel does rather dominate the market. It has much higher eco-credentials and confidently states that it uses 50% less water and produces 50% less carbon than unbranded Lyocell.

Production

Unlike viscose, Tencel is almost exclusively made from eucalyptus wood pulp, but does also use beech and pine. It all comes from managed and FSC certified woodlands.  When the trees are felled, they have their bark stripped and are fed into a chipper to make small chips suitable for the next step in the process. 

The wood chips are then cooked and broken down into raw cellulose using 'biorefinery'. This is a completely closed-loop process which works in a similar way to the Viscose production we talked about above, however with this closed-loop system, nothing is wasted and everything is reused. 99.8% of all the chemicals are contained and reused. As well as creating the fibre for its Lyocell, Modal and Viscose fibres, it also produces a number of useful 'byproducts' which are used in other industries, and 'Black Liquor' which is the leftover bits of the wood pulp, concentrated. It is then used as a biofuel to power their factories. 

Tencel/Lyocell as a fibre

Similar to Viscose, Tencel is a soft, absorbent and drapey fibre. It is recommended for those with sensitive skin and adds a lovely soft, silkiness to garments. There are some wonderful blends that use Tencel in them to add shine and lustre to fibres (Think West Yorkshire Spinners Elements). The fibres are very durable and breathable. It definitely counts as a luxury fibre, and you can feel extra good about using Tencel with all its eco-friendly practices. Be more careful with non-Tencel branded Lyocell though, as the eco-friendly nature is not always guaranteed. 

Bamboo

That leads us quite neatly onto Bamboo fibres. These are produced in the same way as Viscose and Lyocell, and use the fast-growing bamboo plant. Because it uses the same process, I won't go into all the intricacies. Bamboo is often considered to be more eco-friendly than wood-based viscose, due to how fast the plant grows and renews itself, however the manufacturing process is where it falls down, as with the Viscose above, there is a lot of chemical involvement. 

Bamboo is cool and strong, as the other plant pulp fibres above have been. It is lovely to work with and very shiny with a lot of drape. As with all plant fibres, including those above, there isn't much stretch in the fibre, and so you're looking at drape more than elasticity. 

Seacell (Seaweed)

Seacell is very similar to Tencel in many ways. The parent company that creates it, SmartFibre, is a very eco-conscious business with a closed-loop system. 

Seacell varies from other similar products because the properties of seaweed are different to those of wood. As such, the resulting fibre is imbued with minerals and is reputed to have some very positive effects on the body when it is worn, with SmartFibre referring to it as 'nourishing and revitalising' with antioxidants and vitamins as part of the fibre.

The seaweed used in Seacell is 'knotted wrack' and the resulting fibre contains around 19%.

Its other characteristics are similar to the other viscose/tencel/bamboo fibres that we've been discussing. It is compostable, it's silky, strong, absorbent and soft. 

Pearl Fibre

Yep - here's another one you wouldn't have thought about being turned into a fibre. Pearl fibre is created using the same process as milk fibre. 

Cultivated fresh-water pearls are harvested and then crushed and milled into a fine powder. This is then mixed with the viscose fluid and processed into fibre. The finished percentage of pearl in the fibre is usually 0.5-5% depending on the producer.

Pearl fibre is a bright white soft fibre with good skin care properties. This is because the calcium carbonate, amino acids and minerals from the pearl dissolve into your skin when exposed to sweat. The resulting fabric is considered very luxurious (come on, it's pearls!). Definitely one to have a play with if you're a spinner, though you don't tend to find it made into yarns very often. 

More unusual fibres

There are sooo many more types of unusual fibres out there, pineapple, soy, rose, banana, corn and mint. These are created either in the same way as the cellulose fibres we discussed last week, or like the milk, pearl and viscose style fibres we've looked at this week. 

Blends

Blends are where fibres come into their own. I said in week 1 that we wouldn't talk about man-made fibres much. This is the exception, and the reason is that some projects need a bit of strength. The best example of this is for making socks. A standard 75% wool, 25% nylon is recommended for socks because of the warmth and stretch of the wool combined with the strength and resilience of the nylon. 

You can use a small amount of bamboo or other fibre instead of the nylon, but it can affect the elasticity of the yarn, which is important for socks.  

Many of us will have fallen in love with merino/silk blends, or alpaca/cashmere/silk yarns, or (my personal fave) yak/silk blends. They give a mix of drape and lustre, warmth and softness. The blends of fibre also dictate the colour, as you can see in the image above, different blends take the dye in different ways. 

Next?

Once you understand the properties of the different fibres, you can start to understand how best to choose the fibre for your project. Think about the elasticity, the drape, the shine, the warmth, the absorbency. Look back over these blog posts at any time on the website if you need to reference back to read about animal fibres, or plant fibres. 

We're going to have a break from multi-part blogs for a few weeks now, but if there's anything in particular you'd like me to cover, then please drop me a message and let me know.