Textile Structure
how cloth is put together
Concept

Areal weight — where it appears

A fabric's mass per unit area, quoted in grams per square metre, and the number most cloths are sold by. For a woven cloth it is two setts times two counts; for a plain knit it is the stitch density times the loop length times the count.

Named by 4 essays across 3 fields — each of them below, with the objects they name alongside it.

What a coating does to seven properties of a cloth. Seven quantities computed for uncoated fabric, with what each becomes once a film bonds the crossings: the shear a cloth will take — changed in kind; tear strength — changed in kind; the loss from a hole — reversed; wicking — halved; air permeability — reversed; the sett's effect on strength — unchanged in sign; areal weight — added to. Two of the seven reverse outright. The table is a collection rather than a computation, and each row points at the essay whose result it qualifies.

Coated is a state

Almost every mechanism in a woven cloth assumes threads that can move relative to one another — the bias is a mechanism because the crossings rotate, a tear runs because threads gather, a cloth takes a hole without minding because the neighbours pick the load up. A film bonds the crossings. Two of those results reverse outright, the rest change in kind, and a fabric's quoted numbers almost never say which state they belong to.

finishing · Coating Every count that can make 150 g/m² as plain jersey. Areal weight against count for plain jersey in the fully relaxed state: the shaded wedge is every knit between a tightness factor of 1.3 and 1.6, whose weights are kₛ times the tightness times the root of the count. The rule at 150 g/m² crosses it between 15.8 and 23.9 tex, a ratio of 1.51. A plain woven cloth of the same weight can be made from anything between 20 and at least 200 tex, a range of at least 10 to one against the knit's 1.51.

A knit's weight nearly names its yarn

A woven cloth's weight is one equation in four unknowns, and a hundred and fifty grams can be woven from anything between twenty tex and two hundred. A plain jersey's weight has the loop in it and nothing else to spare, and the loop is bounded by the yarn it is knitted from. Put the two together and the loop cancels: the weight is a constant times the tightness times the root of the count, so at one weight the count is fixed to within half again — and in each relaxed state it is fixed to a different half.

setting · Weight A jersey's bending length against its tightness. The wale-wise bending length of plain jersey in the fully relaxed state at 10, 20, 40 tex, across the whole tightness band from 1.3 to 1.6, at the two ends of the yarn's stiffness bracket. At the free bound every count and every tightness gives 10.13 mm. At the locked bound the lines separate by count — 55 mm at 10 tex, 70 mm at 20 tex, 88 mm at 40 tex — and are still flat. The weights along the lines run from 97 to 239 g/m². What the plot cannot show is friction between the loops, which is where a tight jersey's firmness has to come from.

A jersey's drape does not know its loop

A woven cloth's bending length at the free bound turned out to hold neither its count nor its weight — only the fibre. A plain jersey goes further. Its stiffness per width and its weight per area are both a number of loops per millimetre times something about one loop, so the loop cancels at every stiffness the yarn could have; at the free bound the count cancels too, and what is left is the fibre and which relaxed state the fabric is in.

setting · Weight What every 150 g/m² cotton cloth carries into the drying, against its count. The water a plain cotton cloth of 150 grams a square metre holds when it starts to dry, as a share of its dry weight, for every count that can make that weight as one cloth, from 20 to 200 tex — cloths whose thickness runs from 0.33 to 1.06 mm. Laid flat without a spin, every pore is full and the share climbs with the count from 128% to 591%, because a coarser cloth of one weight has larger, deeper holes. Hung on a line for a metre, the holes drain above their own head and every count keeps 101% to 104%. Spun at 1,400 rpm in a full load, every count keeps 40.9%, the finest and the coarsest within 0.1 of a point of each other. What the chart cannot show is the water a drained channel keeps as films, which lifts the two lower lines alike.

A spun cloth dries by its weight

Every plain cotton of 150 grams a square metre contains the same fibre, and the count only arranges it: the coarsest is three times as thick as the finest. Laid out wet without a spin, the thick one holds four and a half times as much water, all of it in its holes. Spun, every one of them keeps 40.9 per cent of its weight and dries in the same time — because a spin empties the holes, and what it leaves in the yarns is not their volume but the fibres' surface, which the weight has already fixed.

cloth · Water

Named alongside it

The objects these essays reach for when they reach for this one.

Loop lengthMunden constantsRelaxationSpecificationTightness factorBending lengthBending rigidityBiasCoatingDrapeEvaporationFilm

All concepts