At the end of this module, you will be able to:
- List the three general classifications of web forming used to manufacture nonwovens
- Describe the meaning of fiber opening
- Describe the purpose of fiber carding
- Describe the advantages and disadvantage of air laid forming
- Describe the advantages and disadvantage of wet laid forming
- List the five major steps of spunbond forming
- List some of benefits that can be achieved with bi-component fibers
- Describe the main difference between the spunbond and meltblown processes
The following key questions are answered in this module:
What are the three broad classes of forming use to create nonwoven materials?
Nonwoven webs can be formed using air-laid, wet-laid and spunmelt processes.
What are some of the benefits of wet-laid forming?
Wet-laid forming produces an isotropic web structure, offers the ability to easily blend performance enhancing additives into the fiber blend, and has higher production rates than dry-laid processes.
What are the basic steps in spunmelt web forming?
To create a spunmelt web, thermoplastic polymer pellets are melted, extruded through a die, stretched and cooled, and then deposited across a porous moving surface.
What is the difference between spunbond and meltblown products?
Spunbound and meltblown fibers are treated in a different manner as they exit the die. The result is that meltblown fibers are much smaller in diameter than the typical spunbound product.
What are bicomponent fibers?
Bicomponent fibers are fibers which are extruder with two different types of polymer within a single fiber. The components do not mix with each other, but by changing the physical relationship of the two components within the fiber, and by changing the composition of the components, the properties of the final fiber can be altered.
Below is a transcript of the video sample provided for this module:
Nonwoven web formation is accomplished using one of three general methods. One, dry-laid. In this process, raw fibers are mechanically aligned, and then laid out. Or they are dispersed into an air stream and collected on a belt to create a sheet. When air is used, the process is referred to as air-laid. Two, wet-laid. A suspension of raw fibers in water is deposited on a porous belt to create a sheet. Three, spun-melt. In this process, polymer is melted and extruded to create filaments, which are then directly laid onto a belt to create a sheet. The two most common variants of this method are spun-bonding and melt-blowing.
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