Tuesday, June 16, 2015

What is Napping

Definition of Napping

Napping is chiefly used to obtain a relatively deep hairy surface, but the degree of depth depends upon the technique used. When a fabric is to be napped, the yarns intended for the construction of the cloth are given only a slack twist in the spinning process. The fabric is passed under a roller that has fine steel wires with small hooks on the ends. The hooks scrape the surface of the fabric pulling up fibre ends out of the yarn.

Napped fabric

The fuzzy finish, produced by napping makes a soft fabric, which provides warmth because of the insulative air cells in the nap. The thicker the nap, the more air cells, and the warmer the fabric. In men’s suiting’s, where long wear is desired, a napped surface acts as a protection against objectionable luster. The fact that stains can be removed more readily from a napped surface is an additional advantage. On the other hand, napping may also serve to cover up a sleazy construction and weaving imperfections. It is generally considered that excessive napping tends to weaken the fabric, especially where a heavy nap has been produced, and to increase any propensity to pill.
Single napping signifies that both sides of a cloth have been napped in one direction; double napping signifies that both surfaces have been napped in opposite directions, which produces greater surface density, increased firmness, and greater warmth. Flannelette, wool flannel and duvetyn exemplify napped fabrics. Cotton and spun rayon fabrics are napped when a soft, fuzzy surface is desired.

The Teasel

Vegetable bars called teasels have been used for napping finer grades of wool fabrics. Long cylindrical rollers containing closely set wires, which act like brushes, also perform the teaseling operation. As the brushes slide over the revolving fabric, they pull the top fibres and raise the protruding ends above the surface of the cloth in the form of a fleece like nap. If a heavy nap is desired, teaseling is repeated several times.
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