Textile Structure
how cloth is put together
Generator

Which gives first under a PTFE laminate

Which gives first under a PTFE laminate
Which gives first under a PTFE laminate. Two pressures against the sett for a 40 tex polyester cloth under a PTFE laminate: the bound on what the film will hold over one hole, and what the cloth's own threads will hold in a burst test. They cross at 22 threads per centimetre — below that the film is the weak link and above it the cloth is. Both are bounds computed from stated properties rather than measurements.

Two pressures against the sett for a 40 tex polyester cloth under a PTFE laminate: the bound on what the film will hold over one hole, and what the cloth's own threads will hold in a burst test. They cross at 22 threads per centimetre — below that the film is the weak link and above it the cloth is. Both are bounds computed from stated properties rather than measurements.

2 essays call coat-curve. The drawing above is what it returns with no arguments at all; every call below passes it something, because a placement that passes nothing draws whichever member of the family the generator happens to default to rather than the weave its essay argues about.

Where it is called

Every figure listed here is drawn from this one rule.

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. After the loom

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.

 A coating over the hole it has to bridge. Four warp ends of 40 tex seen end-on at 20 per centimetre, with a 120 micrometre PVC film over them. The film is supported everywhere it lies on a thread and unsupported over the 252 micrometre clear span between them, which is the same span at every hole in the repeat. The film's thickness is drawn to scale against that span; the bulge is exaggerated. At 20 MPa the film will hold at most 381 bar, which is a bound and not a prediction. Cloth doing a job

A coated cloth fails at its holes

Spread a film over a fabric and it is supported everywhere it lies on a thread and unsupported over every hole. A woven cloth's holes are all the same size — exactly, because a repeat is a repeat — so the film has one span to bridge and the fabric has a burst pressure rather than a distribution. A nonwoven gives it a distribution, and a membrane fails at the largest hole it meets.

The whole library · All essays