TABLE OF CONTENTS Polymers are used for the fibers in nonwoven webs and for the resins and additives used to bond, coat, and provide other properties to the fiber formed web.
In meltblown, spunbonded, and electrospinning processes the polymer is the fundamental raw material supplied to the process and the forming of filament fibers is an intermediate stage in the forming of the web. Web properties for these processes are determined by the appropriate choice of polymer based on its properties and selection of the process conditions for forming that polymer into a fibrous form.
On the other hand, formation of webs by the air laid, dry laid and wet laid processes begins with a raw material that is already in fiber form. These are shorter nonfilament types of fibers provided by some form of outside supplier. The choice of fiber properties is the guiding criterion in the design of the web.
Organic fibers and resin binders are composed of polymers. Their properties and processability are very much dependent on the chemistry and properties of the polymers from which they were made. A listing of the structures of many of the polymers used for nonwoven materials is tabulated in Table 4.1.
| Polymer | Type(s) & trade name(s) | Chemical name | Application | Structure |
|---|---|---|---|---|
| Cellulose | Woodpulp Vegetable Fibers
Cotton | Repeat unit:anhydro-beta-cellobiose |
