At the end of this module, you will be able to:
- List the three general classifications of web bonding used to manufacture nonwovens
- List the three different techniques for apply binder to a nonwoven web
- Describe solvent bonding
- Describe thermal bonding
- List some of the techniques for heating and bonding a nonwoven web
- List the three general types of mechanical bonding
- Describe the two general types of finishing processes
- List some of the benefits that can come from nonwoven finishing
The following key questions are answered in this module:
What are the three broad classes of bonding use to create nonwoven materials?
Nonwovens can be bonded together using chemical, thermal or mechanical processes.
What are the advantages of using foam to apply binder to nonwoven materials?
Applying binder as a foam leads to higher production rates and lower drying costs than binder application by web immersion. Foam allows low application rates without the need for a containment enclosure which is required by the spray application technique.
How does thermal bonding work?
Thermal bonding works by heating a web and partially melting polymeric fibers, allowing them to bind to each other or to other fibers in a blended material.
What are three mechanical bonding techniques?
Nonwovens can be mechanically bonded together by needlepunching or spunlacing, which are entanglement processes, or by stitchbonding which uses woven threads to help hold fibers together.
What is one advantage of spunlacing?
Spunlacing uses high pressure water to entangle fibers and can be used to create surface patterns in the final web.
Below is a transcript of the video sample provided for this module:
Most of the polymers used in the spun-melt process create fibers that do not wet and are inherently water-repellent or hydrophobic. Many nonwovens are used in diapers, wipes, and other hygiene-related products. For these products, liquid transfer and absorbency are essential to how they function. One of the most important finishing coatings is the addition of a rewetting compound, which converts the sheet into a hydrophilic material, which is one that wets and allows water to pass through.
This is typically done by passing the bondage sheet over a roll wetted with the rewetting compound, or a surfactant. After the application, the sheet must be dried before being wound on the parent roll. Other coatings used include antistatic compounds, softeners, and additives to enhance product performance and customer satisfaction.
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