Mercerized cotton is a special kind of cotton yarn that is more
lustrous than conventional cotton. It is also stronger, takes dye a
little more readily, makes the yarn more resistant to mildew and reduces
lint. It also may not shrink or lose its shape as much as "regular"
cotton.
Mercerisation is a treatment for cellulosic material, typically cotton threads, that strengthens them and gives them a lustrous appearance. The process is less frequently used for linen and hemp threads.
Mercerization, the process by which mercerized yarn is
made, is named for the British chemist John Mercer, who developed the
process and received a patent for his work in 1851.
Mercer found that adding caustic soda (lye) or sulfuric acid to
cotton made the fiber swell and straighten. No one was too impressed by
that, but in 1890 Horace Lowe developed a process by which
caustic soda
was added to the yarn under high tension, which added the luster that
mercerized cotton is famous for today.
Thread :
The modern production method for mercerised cotton, also known as
"pearl" or "pearle" cotton, gives cotton thread (or cotton-covered
thread with a polyester core) a sodium hydroxide bath that is then neutralized with an acid bath. This treatment increases lustre, strength, affinity to dye, and resistance to mildew. On the other hand, it also increases its affinity to lint.
Cotton with long staple fibre lengths responds best to mercerisation. Mercerised thread is commonly used to produce fine crochet.