Woven Fabrics - Fairchild Books

warp
yarn
Figure 4.14
Making chenille yarn: Filling yarns are cut between each section of warp leno.
to 1 ⁄128 inch (0.20 millimeter) wide. These yarns can be
supported by loosely twisting one or more fine-filament
yarns around them (e.g., two 15-denier nylon yarns).
This increases its strength and abrasion resistance.
Metallic yarns are mostly used for decorative rather
than functional purposes; a wide range of colors and
effects is available. Metallic yarns tend to be expensive.
Lurex Co., Ltd. is a major metallic yarn manufacturer.
Yarn Numbering Systems
Yarns are bought and sold by the pound. Knitting mills,
for example, purchase their yarn requirements in pounds
rather than in yards. Even home knitters purchase yarns
in packages sold by ounce or gram weight.
Yarn numbering systems are used to express
a relationship between a unit length and weight of
yarns—either meters per gram or yards per pound. The
relationship between unit length and weight also reflects
the diameter or thickness of a yarn. This is because a
yarn of low weight per unit of length would be finer
(thinner) than a yarn with a higher weight per equal
unit of length. However, the diameter of the yarn may
vary for any given yarn number because of differences
in the specific gravity of the fibers from which yarns
are made, and because some yarns are highly twisted
whereas others have low twist.
The terms yarn numbers and yarn sizes are used
interchangeably. Despite the words “yarn size,” bear in
mind that the size (or number) expresses a relationship
between a unit of length and weight, and only a close,
but not exact, relationship to diameter or thickness.
There are two main numbering systems in use: the
denier system, which is used for all filament yarns, and
the yarn-count system, which is used for all spun yarns.
YARNS AND SEWING THREADS
A 81 F
filling
yarn
A third system known as the tex system was developed
to bring all yarn numbering systems into a single system
for all types of yarns.
The Denier System
The denier system is the simpler of the two numbering
systems. In this system, heavier and usually thicker
filament yarns are designated by higher denier numbers.
Very fine yarns, of 10 denier, for example, are used in
sheer hosiery. The heavy, coarse yarns used in carpeting
are around 2,000 denier. The denier system is called a
direct system because higher denier numbers designate
heavier (thicker) yarn. A 100-denier nylon filament has
twice the weight of an equal length of 50-denier nylon
filament. Thus the system is based on weight in grams
per 9,000 meters.
A 1-denier yarn is a yarn in which 9,000 meters, if
weighed, would equal 1 gram. A 2-denier yarn would
weigh 2 grams per 9,000 meters, and so forth. Thus the
yarn has twice the thickness per unit length.
Filament yarns are sold by indicating the number
of filaments the yarn contains, and the twist as well
as the denier size. For example, a 300-10- 1 ⁄2 Z filament
yarn indicates a yarn of 300 denier in size, containing
10 filaments with 1 ⁄2 TPI of Z twist. Each filament fiber
in this yarn would be 30 denier. A 400-40- 1 ⁄2 Z would be
thicker than the 300-10- 1 ⁄2 Z, but have finer filaments
because each filament fiber would be a 10-denier fiber
and thus finer.
The Yarn Count System
In the yarn count system, the yarn count number is
inversely proportional to weight. This system, therefore,
is indirect. A 50-count spun yarn has twice the
weight (thickness) of a 100-count spun yarn. The