TABLE OF CONTENTS Chapter 1 Section 1.7 classified nonwovens by process and presented brief descriptions of each process. More detailed discussions of each process follow.
The fundamental process for air laying a web is to hammer mill dry pulp fibers into an air stream and deposit it onto a moving collector fabric. The important products of this process are wipes and absorbent materials for hygienic products, incontinence pads, and diapers. The absorbent products may incorporate superabsorbent (SAP) materials to be blended with the fibers. Figure 1.1 of Chapter 1 diagrammed the MTS pilot process for producing air laid products. The web former is a Dan-Web dual head former produced by Dan-Webformin in Denmark. The process also provides fiber metering systems to feed long synthetic fibers to the air laid forming device. SAP powder is added through "dosers" at the forming heads. A latex spray provides for web bonding. The wet resin treated web is dried by a flat bed through-dryer.
Air laid webs can also be bonded by thermal bonding, hydroentanglement, and needle punching. Pittman and Irish [126] examined the effects of thermal bonding air laid webs with bicomponent sheath-core fibers.
At one time the air laid process was reported as producing an automotive carburetor air filter for Fram Filters [127] [128]. This product has since been discontinued. The author is unaware of any other filter media produced by the air laid process.
A variation of the air laid process is the use of formers...
