Expert Instructors Share Key Lessons to Be Learned at the Upcoming Fiber and Filament Extrusion Short Course

The Nonwovens Institute (NWI) is offering its popular Fiber and Filament Extrusion Fundamentals Short Course July 23-25 at the Centennial Campus of North Carolina State University in Raleigh. This course, presented in partnership with INDA, The Association of the Nonwoven Fabrics Industry, will be led by expert instructors, including Carl Wust, Ph.D., NWI Emeritus Member and formerly the manager of research and development for FiberVisions® Corporation; an Indorama Ventures Company, and Behnam Pourdeyhimi, Ph.D., professor and executive director of NWI at NC State University.

The Fiber and Filament Extrusion Fundamentals course is designed to provide attendees a firm understanding of the critical variables and process parameters required to optimize extrusion practices to enable nonwoven innovation. In addition to spunbond and meltblown nonwovens, the course will consider staple-fiber applications, the process for crimping and cutting fibers, and fiber finishes, highlighting the differences between filament extrusion and staple-fiber extrusion. The course is designed to be accessible and valuable to attendees who do not have prior hands-on knowledge in fiber extrusion, as well as those who have a strong foundational understanding of extrusion fundamentals.

The following article provides perspectives from Dr. Wust and Dr. Pourdeyhimi on the compelling points that will be covered during this course and why extrusion is such a key variable in the success (or failure) of many nonwoven products.

What can attendees expect to learn from the Fiber and Filament Extrusion Fundamentals Short Course?

Carl Wust, Ph.D., NWI Emeritus Member (formerly FiberVisions)

In nonwovens, we tend to focus on spunbond and meltblowing processes, but a lot of nonwovens are made by carded bonding, and major companies remain focused on making staple fiber today.

My former company, FiberVisions, operates the world’s largest PP staple-fiber plant housed under one roof. The plant, which is located in Covington, Georgia, has a nameplate capacity of 110 million pounds per year. During its peak of production, the plant was producing staple fiber for one product  targeted at carded thermal bonded cover stock for baby diapers. In the 1990s, baby diaper companies started switching to spunbond for cover stock, so we had to find new applications. Today the Covington plant produces staple fiber for a variety of end-use products – none of which are cover stock – so we learned a lot over the years about how to optimize staple-fiber production to suit the needs of varied applications.

“The versatility in blending of different fiber types and adding finishes is what I think sells staple fiber, and I will provide the Fiber and Filament Extrusion Fundamentals course attendees an understanding for how they can leverage this versatility to the benefit of nonwoven applications.”

During the Fiber and Filament Extrusion Fundamentals course, I will share the key learnings I have gained throughout my career. I will walk the attendees through the fiber production process, explaining how a staple-fiber production works, how to process blends and other important factors to consider when spinning and processing staple fiber. I will show-and-tell with extruder screws and spinnerets and describe polymers and finishes. I will explain how to cut and crimp fiber, how to put finish on the fiber, and how to bale the fiber up and prepare it for shipment.

One of the important advantages of carded staple fiber is you have flexibility to make different types of fibers – such as trilobal fibers or hollow fibers – with relative ease. You can incorporate such capabilities as antimicrobial, ultraviolet protection and electrostatic charging. When producing sheath/core bicomponent fibers, you can adjust the sheath properties to enhance the bonding strength and loft of through-air bonded fabrics. Staple fiber also can lead to nonwovens that blend cotton, viscose, etc.

The versatility in blending different fiber types and adding finishes is what I think sells staple fiber, and I will provide the Fiber and Filament Extrusion Fundamentals course attendees an understanding for how they can leverage this versatility to the benefit of nonwoven applications.

Behnam Pourdeyhimi, Ph.D., Professor and Executive Director, NWI

When it comes to the extrusion process, you really need to understand the material, process, performance interactions as they relate to fiber and filament formation.

During the Fiber and Filament Extrusion Fundamentals course, I will explain different polymer characteristics and the requirements for different processes. Filament formation is very similar to what you would experience in a spunbond nonwoven application. Meltblown, on the other hand, is very different from spunbond or filament production. We will highlight the critical material characteristics that need to be considered to enable innovation around fiber and filament formation in different process scenarios.

“Filament formation is very similar to what you would experience in a spunbond nonwoven application. Meltblown, on the other hand, is very different from spunbond or filament production. We will highlight the critical material characteristics that need to be considered to enable innovation around fiber and filament formation in different process scenarios.”

During the course, I will explain how you can “tune” fibers to provide unique capabilities such as orientation, crystallinity, strength, uniformity and dyeability. I will answer the question, “For a given polymer, how do we control the process to achieve the desired characteristics?”

When you look at polypropylene (PP), polyester (PET) and polylactic acid (PLA), for example, these are very different materials. I will consider the unique characteristics of each and how the process should be controlled to enable the end product you are aiming to create. We will consider, for example, how we can enable materials like PLA to overcome challenges such as shrinkage and crystallinity so it can be employed in a wide variety of applications.

Nonwovens can be made up of fully drawn fibers (fibers have a high degree of orientation) or partially drawn (fibers are only partially oriented). The majority of products use fully drawn fibers, but moldable structures, for example, require partially oriented fibers to facilitate molding.

PP is a model material because it offers fast crystallization and has strong bonding characteristics to support partially or fully oriented structures without exhibiting shrinkage. PET and PLA, on the other hand, are slower to crystallize and they don’t bond well.  When the PET and PLA fibers are partially oriented, they exhibit significant shrinkage, which is a challenge in applications such as moldable structures. However, there are additives and bicomponent options that can overcome such challenges. Some aspects of this will be covered in the class.

So, I think it is safe to say, those who attend the Fiber and Filament Extrusion Fundamentals course will leave with the knowledge to make significant improvements in a variety of nonwoven and filament production scenarios.

Are you interested in attending the July 23-25 Fiber and Filament Extrusion Fundamentals Short Course?

Dr. Wust received his Ph.D. in Polymer Engineering from the University of Tennessee in 1982 and joined Hercules Inc. in Wilmington, Delaware, where he initially worked on polypropylene resin developments for fibers, controlled permeability films, and even solid rocket propellants. Over the ensuing 40 years, Dr. Wust transferred to Covington, Georgia, where he is currently located, accepted positions of increasing responsibility, and made numerous contributions to the advancement of fiber and fabric technologies that have benefited our every-day lives. In 2022, Dr. Wust retired as manager of research and development in the Americas at FiberVisions, an Indorama Ventures company.  

Since the early 2000s, Dr. Wust has been an active member of NWI. He has served on the Industrial Advisory Board Executive Committee, served on and, most recently, chaired the Strategic Scientific Advisory Board (SSAB) and led the Institute’s Materials Research Focus Group (RFG).  

Dr. Wust has been a significant contributor to the content of training programs offered by NWI and INDA, The Association of The Nonwovens Industry, and mentors 4-6 Ph.D. candidates in the field of engineered textiles annually. He currently serves as an Emeritus Member at NWI and continues to support the mission of the Institute through participation on Research Focus Groups, student mentoring and as a training course instructor. 

Dr. Pourdeyhimi joined North Carolina State University as a Research Associate immediately after completing his Ph.D. at the University of Leeds in 1982. Soon, he left for other opportunities, Cornell (2 years), the University of Maryland (11 years) and Georgia Tech (4 years) before returning to NC State in the 1998-1999 academic year. Dr. Pourdeyhimi joined NC State at the rank of Full Professor and soon after received the Klopman Distinguished Professorship for his work in textile materials.

Early in his career, Dr. Pourdeyhimi focused on the development of tools for characterizing various materials including nonwovens, medical devices, composite materials, etc. For this body of work, he received the ASTM D-13 Dewitt Smith Medal. In particular, his work on image analysis won him the Fiber Society Distinguished Scientist Award in 1994. He also was selected as the Fiber Society Lecturer where he traveled broadly to present his work to industry and academia. He later served as the vice president and then president of the Fiber Society.

Dr. Pourdeyhimi is best known for his contributions to nonwovens and establishment and the growth of nonwovens at NC State. Dr. Pourdeyhimi joined NC State in part to take on a leadership role in the Nonwovens Cooperative Research Center (NCRC).  He was appointed as the director of NCRC in 2000 and he successfully led the transition of NCRC into what is now known as The Nonwovens Institute (NWI).