Mercerized Handloom Cotton Fabric by Folksmarket.com

Often known as Pearl Cotton, Mercerization is a chemical treatment of Cotton Fabric and Cotton Yarn to give it more shiny, lusturous appearance and also increases its strength. Cotton Fabric is the most widely used fabric, be it in Handloom or Powerloom. Around 60% of all the Fabric used for Apparels and Home Furnishing, come from the cotton. The first use of Cotton assigned to India from where it reaches to different part of the world. The earliest use dates back to 3000 BC!

The English name of cotton is taken from the Arabic ‘(al) qutn’. The fibre is often spun to make breathable textile which is soft and most widely used natural fibre. 

It thus become obvious that lot and lot of experiments started to make this fabric more appealing to the consumers. Sometimes the fibre is altered keeping in mind the end result and use but sometimes its pure lateral thinking and experiment.

Mercerization of Cotton, though now symbolizes a lab treatment, is the name after the scientist who experimented it clinically. 

Cotton straight from the Farms

Before that lets look at what actually comes out of the nature that we use as Cotton Yarn. 

Cotton is a soft staple fibre that comes around the seed in the form of a ball, thus Cotton Ball. Each fibre is produced from an individual seed rooted through the base. One cotton ball has approximate 5,000 seeds altogether. The fibre starts out as projecting a hollow sheath and fresh layer is laid down in the inside of the sheath. The fibre, at this time, looks like a solid cylindrical rod with a central lumen consisting entire of cellulose. The ball then burst because added lateral movement of fibre produces a force. The fibre dries up due to the sun and collapse. The fibre is flat and there are alternating left and right twist per turn. The cotton also known as Kapas locally is then collected from the field and reaches to the mills for further processing. The carding machine in cotton mills turns the fibre into cotton yarn. Normally cotton fabric shrinks by 3% until pre-treated to neutralize that effect.

 

Mercer, Mercerization and Shine

Mercerization of the Cotton is the treatment of cotton fibre with Caustic Soda. John Mercer in 1851 got the patent for his work that he did with cotton fibre using caustic soda, sulphuric acid and many other chemicals. He listed all the changes in the fibre after treating it with various chemicals. One important point he mentioned, was that the fibre swelled, rounded and straightens out once treated with Caustic Soda. Though fibres swelled and straighten, there was no luster and the British Cotton trade industry showed NO INTEREST in this invention and the invention remained obscured for 40 years till 1890 when Horace Lowe showed what the Cotton industry missed out in these 40 years.

In 1890, Horace Lowe suggested that by applying Mercer’s caustic soda process to cotton yarn or fabric under tension, a resultant high lustre is observed in the yarn. The tension, which was missing in Mercer’s process, makes the surface of the fibre smooth and rounded and results in the reflection of the light off the surface. This is similar to the glass fibre phenomenon. The Mercerization was huge success and Cotton Industry embraced this process overnight. Lowe was gracious enough not to use his name even partially and the process is still called Mercerization and used only for Cotton.

Use of Mercerized Cotton

Merc Cotton by Folksmarket.com

Mercerized Cotton by Folksmarket.com

Though mercerized cotton abbreviated as merc. in textile industry finds it use in virtually all the things like apparel, furnishing yet its most important use is for Crochet.

Tension and Lustre

It is established that without tension there is no lustre. The more glass like fibre, the more the lustre will be. In the mercerization, cotton is held under tension for 10 minutes and treated with 21-23% of NaOH (Caustic Soda).

As the twist is required to give tension, it was found that fine, long staple cotton fibre gives the best adhesion required for tension. Thus it is those type of cotton that is selected for the mercerization process. In India, the cotton grown over Deccan Plateau under ideal condition and Egyptian cotton are good for mercerization.

Mercer while conducting his experiment found enough evidence to suggest that after caustic soda treatment there is a dramatic increase in the absorption level (a good 7.5%-8.5%) of the cotton fibre with all other variables keeping in constant.

The increase affinity in absorption level of the fibre holds true for direct dye-stuffs. This augurs well for the cotton. For dyeing its very important that fibre should have good affinity level with that dye. This affinity was due to Caustic Soda treatment. The cotton in its roving state that is no twist, is more likely to absorb water and dye then it is twisted. The amount of dye/water absorption depends a lot in twist. So you can very well assume that twisted yarn absorbs dye/water proportionally.

Mercerization, not only increase the lustre and dyeing absorption but also increase the strength of the cotton and resistance to mildew (a kind of molds or fungus found in plant)

Ammonia versus Caustic Soda

Mercerization is also done by Ammonia and these days they are done more frequently than the Caustic Soda. The effect of the fabric is different in two cases. The resistance to abrasion tears and tensile is significantly improved in ammonia mercerized cotton. The ammonia mercerized fabric is more softer than caustic soda mercerized fabric. The difference in effect is due to the smaller molecule of ammonia which led it to penetrate the cotton fibre complete than caustic soda. There is a less fibre swelling and fibres are more pliable and allow them to recover the bend more easily.

Nevertheless, it is the great Mercer and gracious Lowe who showed the world how a human intelligence can break the hurdles and create something that allows the textile industry swing with the mood of folks. This piece Celebrate such folks!!