Page 46 - Curriculum Visions Dynamic Book

Acetate fibre
Acetate is made by reacting cellulose
from wood pulp with acetic acid. After further chemical treatment (known as hydrolysis) cellulose acetate is formed, which is soluble in cheap solvents such as acetone.
The acetate is made into fibre by extruding it
through a spinneret and drying it in a current of warm air. It was first marketed in 1921 under the name Celanese®.
It became a successful product because it had a silky lustre and good crease-resistant properties. It does not shrink when washed.
Special dyes have had to be developed for acetate since it does not accept dyes ordinarily used for cotton and rayon.
Acetate, with its silky look and crease resistance, was widely used for blouses, dresses, coat and drape linings, and upholstery. It was also used as the material for cigarette filters. Its use has declined a little since the mid-twentieth century because of competition from polyester fibre, which has similar properties but is less expensive to make.
Microfibre
People have long treasured the fineness of some natural fibres in making fabrics. However, naturally fine fibres are scarce, and until recently it has not been possible to make very fine man-made fibres. In fibre terms a very fine fibre
is less than 1 denier (1 g weight per 9,000 m of fibre). This kind of fibre, which is finer than silk, is called a microfibre. Most new microfibres are made of polyester.
The advantages of a microfibre are often in lightness. For example, rainwear made of microfibres will still let moist air pass through, but it will be much thinner than conventional fabric and so is lighter and more comfortable to wear (see also page 18).
Of course, a thinner fibre is liable to be weaker than a thicker fibre, so special care has to be taken to make microfibres very strong. Microfibres are not suitable as insulating fibres because they do not trap much air.
(Above) A shiny acetate fibre finish makes this a suitable silk substitute often used to line suits and jackets. Common
or trade names for acetate fibres include Tricel® and Arnel®.
Microfibre
Microfibre is finer than silk, which is the finest natural fibre.
46