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The yarns produced in the spinning process create some form of decoration in the fabric. In the formation of the fabric, decoration is also obtained by the pattern of the construction. The checkerboard pattern of the plain weave, the variations of the basket weave, the diagonal of the twill weave, and the luster of the satin weave produce simple designs. This type of decoration becomes more elaborate as fabric construction advances to the use of the third dimension in the pile weave, to the open-mesh lace like effect of the lappet weave, and to the intricate effects of the jacquard weave, as well as to the various knits and other types of fabric formation.
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When fabric passes through finishing operations, it may be given lustrous effects that contribute further to its final appearance. Other finishing processes create the additional effects of soft napped surfaces and the crinkled designs seen in seersucker, and similar crepes. Dyeing makes an important contribution to fabric decoration by the many beautiful colours it produces and the colour harmonies obtained by combinations of the various dyeing methods. A finishing given to a cloth called as "Flocking" can still further enhance fabric.
The technique of adhering minute pieces of fibre is called flock. To form designs on fabric has been used to a limited extent for about 600 years. It has become more widely used in recent years because of modern methods. |
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Using a suitable adhesive (instead of a dye), a design is roller printed onto a fabric. Then, flock of cotton, wool, viscose rayon, nylon or acrylic is applied to the fabric in a manner that causes it to adhere in an upright position and produce a pilelike, velvet-textured design. The flock is usually of coloured fibres, thereby adding to the decorative appeal.
Cotton and wool waste fibre are often ground or random-cut into flock. However, since such production results in uneven and or regular ends that do not affix as well as straight ends. Precision-cut flock of rayon and other manmade fibres such as nylon and acrylics are preferred. The flock generally ranges in length from 2 to 6mm.
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Flocking may be accomplished by a mechanical method of beating the underside of the adhesive-coated fabric with rotating multisided beater bars as the flock is shifted onto the fabric. The fabric's vibrations, produced by the beater bars, cause the flock to flow over the surface of the fabric and stand erect those fibres that do not land flat on the adhesive. Continued vibration causes the erect fibres to penetrate deeper into the adhesive, and as more fibres fall on the already erect fibres, they become similarly oriented and build up a pile effect. With this method, which has the advantage of being relatively inexpensive, the fibers become more deeply embedded and, therefore, more permanently attached. However, since many fibres adhere at various angles, the flocking may not be as dense as desired.
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The Giroud process is a different mechanical method. Sheaves of fibre, such as tow, are fed into a device, which holds the fibres vertically and cuts them into predetermined, uniform lengths. The cutting operation is regularly repeated causing continuous horizontal pressure against the fibres. While remaining aligned in a vertical position, the flock is continually moved horizontally in a feeding guide towards a conveyer belt on, which is a fabric substrate coated with an adhesive. As the flock comes in contact with the adhesive, it is implanted in it to form a very erect, compact, dense pile superior to that possible by other methods. The flock may be cut in any length and may be made of any type of fibre, including glass and metal.
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Another technique utilizes an electrostatic principle. As the flock is shifted onto the fabric, it passes through an electrostatic field, or electrically charged air space. This directs and propels the fibres in the longitudinal direction of the current toward the fabric, which causes them to stick to the adhesive in an erect position. This method can produce a denser flocking because the fibres uniformly adhere, upright to the fabric. However, it is a more expensive technique, requiring more complicated apparatus and better-quality flock.
Depending upon the background fabric, or substrate, the depth of the pile, the flock used, and the pattern, flocked fabrics may be created for various purposes. Flocking is used for household goods such as curtains, draperies, carpeting and wearing apparels.
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