Origin

Rayon is the first fibre to be made by man and was sold as an artificial silk. It is made from the cellulose in the pulp of trees or cotton. The invention of rayon came when a disease that affected silkworms threatened to halt silk production in France during the 1860’s. Count Hilaire de Chardonnet was studying a way to save the silk industry and came up with the idea of creating an artificial silk. During the year 1885 he created the first usable fibre from cellulose. Until the year 1925 it was known as artificial silk and the Federal Trade Commission renamed the fibre Rayon.

Preparation

When made from trees Rayon normally is based off the pulp off pine, spruce and hemlock trees. There are three main processes in the preparation of Rayon fibres. These are purifying cellulose, producing filaments and spinning.

The first step to preparing Rayon is purifying cellulose. This happens when sheets of cellulose are put in a sodium hydroxide solution which will turn the cellulose alkaline. The sheets are then dried and shredded before being left in metal containers for up to 3 days. After this the shredded cellulose and mixed with carbon disulfide where it becomes a honey like consistency. The mixture is then aged for up to 5 days before being filtered to remove any impurities. The mixture is next put through a spinneret into a tank of acid which turns the mixture into a solid substance.

The next step of producing Rayon Fibres is called spinning. This is when the fibres are spun into yarn ready to be turned into fabric. The way the fibres are spun depends on what type of yarn is desired. The fibres are spun onto spools ready to be turned into fabric.

Rayon being Manufactured

Aesthetic Properties Of Fibres

Rayon is a fibre which is very easy to dye in any colour due to its high absorbency. It does not produce any static and does not pill. Rayon is not usually damaged with the use of acids or bleach to its surface and on its own when not blended has a high lustre. The downside to Rayon is that it is prone to creasing and shrinks under high heat. It also does not resist mildew.

Rayon Yarn

Origin

Lyocell is made from cellulose which is found in all plants. Making fibres from cellulose was a common practice in the 19th century onward although nobody made one commercially until the year 1989. Lyocell was first produced in the year 1992 by the company Courtaulds under the name of Tencel. It more commonly became known as Lyocell in the year 1996 in the United States.

Preparation

Lyocell is produced from the cellulose found in the pulp of hardwood trees. such as Oak and Birch. The trees are harvested and then transported to the mill where the trees are cut to 20ft in length. The trees are then sprayed with powerful jets of water in order to remove the bark. The wood is then put through a chipper before being placed in a vat which is filled with chemicals that will soften the wood into a pulp. After the wood has become a pulp the pulp is washed and bleached before being dried in large sheets. The sheets of pulp now consists of the cellulose of the trees and are then rolled onto spools.

Next the sheets of cellulose are unrolled off the spools once they reach the lyocell mill and are cut into squares each measuring one inch. The squares are then put in a hot pressurised vessel which has been filled with a chemical called amine oxide.

After the cellulose has been soaked in the amine oxide the cellulose will dissolve into a solution and is filtered through a system in order to make sure all the remaining wood chips are removed.

The solution is then put through a spinneret which forces the solution into the desired fibre shape. The solution is forced through the spinneret into another amine oxide solution which hardens the strands into the desired shape.

The lyocell fibres are then dried and a soap or silicone based lubricant is coated over the fibres. Finally the lyocell fibres are taken to a crimping machine. This machine compresses the fibres to add its texture and is finally passed through a carding machine in order to separate the fibres. The lyocell is now ready to be shipped to a fabric mill and turned into fabric.

lyocell-bamboo-fiber-275758 — Lyocell Fibres

Physical Properties Of Fibres

Lyocell is a very strong a durable fabric. It is a hydrophillic fabric meaning is it has excellent absorbency. It is much stronger than wet and can absorb even more than cotton can.

Lyocell is an anti-bacterial fabric and is good for sensitive skin. It is also very breathable as a fabric and can be used on its own or mixed with other fabrics.

Aesthetic Properties Of Fibres

Lyocell is a very soft and lightweight fabric. It is resistant to creasing and can simulate the look of fabrics such as silk, leather or suede. Due to this depending on how it is prepared it can either have a high lustre or a low lustre. It is a easily dyed fibre with an excellent drape.

References

Made How. (2018). Lyocell . Available: http://www.madehow.com/Volume-5/Lyocell.html. Last accessed 27/11/18.

American Fibre Manufacture Accosiation Inc. (2018). Lyocell. Available: http://www.fibersource.com/fiber-products/lyocell-fiber/. Last accessed 27/11/2018.

Simplifi fabric . (2018). Lyocell . Available: https://www.simplififabric.com/pages/lyocell. Last accessed 27/11/18

Papnews. (2016). Wood pulp exports from Russia up 10 per cent in 2015. Available: https://www.papnews.com/wood-pulp-exports-from-russia-up-10-per-cent-in-2015/. Last accessed 27/11/18.

exportsindia. (2018). Lyocell Bamboo Fibre. Available: https://www.exportersindia.com/chinapopulus/lyocell-bamboo-fiber-china-275758.htm. Last accessed 27/11/18.