Nonwovens Glossary - INDA

Doffer loading
Refers to fibers firmly fixed or plugging the doffer roller’s wire preventing the doffer comb
from removing the web.
DOP
Dioctylphthalate (diethyhexyphospate) is a viscous liquid that is heated into an aerosol in the
critical particle range to challenge a filter. The aerosol’s presence upstream of the filter and
downstream are measured to determine the media’s efficiency. DOP is used to measure HEPA
and ULPA media performance.
Drape
The ability of a fabric to fold on itself and to conform to the shape of the article it covers.
Draw-through
An air circulating fan located downstream of the heating or cooling coils, humidifiers and
filters in an HVAC system.
Drawing
A process of stretching a filament after it has been formed so as to reduce its diameter. The
ratio of the final length to the initial length is called the draw ratio. Controlled stretching of
the filament by a factor of 4 to 10 causes the molecular chains to become aligned (oriented)
along the fiber axis and makes the filament stronger.
Dry spinning
The process in which a liquid polymer solution is passed through spinnerets into a heated air
stream that drives off the solvent and coagulates the polymer into fibers. Sometimes referred
to as Solvent Spinning.
Dry forming or dry laying
A process for forming a web from dry fibers by using carding equipment. Air laying refers to
the formation of random webs with a stream of air.
Dry laid nonwoven
Dry laid web of fibers that has been bonded by one or more bonding techniques to produce a
fabric with integrity.
Dry laid web
A web of fibers produced by the dry laying process.
Dry scrubbing
The process of removing heavy concentrations of gaseous contaminants from an airstream by
the use of some specially designed adsorbers or chemisorbers.
18 Nonwovens Glossary