Eastman, Kingsport, Tenn., USA, explains that with the ability to produce high-performing, high-strength synthetic nonwovens on standard papermaking equipment using its Cyphrex™ microfibers, product developers can achieve performance without any of the final product trade-offs that typically come with using a combination of synthetic and cellulosic fibers. Due to their unique geometry and composition, these microfibers behave differently than existing synthetic fibers, as they process very much like cellulose fibers.

Unlike most synthetic fibers, Eastman Cyphrex flat polyethylene terephthalate (PET) microfibers process well on inclined wire, rotoformer, and fourdrinier machines. These microfibers can be run at standard consistency (1.0% to 3.2%) on the wet end, disperse easily with minimal sheer, and can blend with cellulose to improve strength and formation of paper products.

 

Another benefit is that the microfibers can be easily run as 100% of the fiber furnish on conventional papermaking machinery and can be processed very much like cellulose on flat wire machines, a benefit not typically expected from synthetic fibers.

  

Overall, PET microfibers behave differently than other synthetic fibers, providing benefits previously unseen. For example, unlike other non-fibrillated synthetic fibers for wetlaid applications, Cyphrex microfibers improve strength, formation, and permeability of high-strength paper products — without requiring significant processing compromises. In fact, uniformity of the novel flat fiber substrate made on a fourdrinier or rotoformer machine is similar to that seen on an inclined wire machine, Eastman points out.

These microfibers also can be converted to nonwoven substrates without the processing and performance tradeoffs often observed when incorporating existing synthetic fibers. Eastman Cyphrex microfibers provide excellent wet strength, they can be run at standard consistency on the wet end, and they provide high dry strength without the use of a wet strength agent or bonding agent, the company says, adding that they do, however, respond exceptionally well to wet strength agents when those materials are used.

 "Eastman Cyphrex™ microfibers are well-suited for paper, pulp, and nonwoven industry technical professionals who want innovations that can help them stay ahead of product commoditization," says Jon Woods, GM, nonwovens microfibers, Eastman. "Because technical professionals want synthetic fibers to enable product performance without the processing challenges that often accompany them, Cyphrex microfibers could enable new attributes to allow for more customizable applications in the high-strength paper applications."

In addition, these microfibers provide impressive tensile, tear, and burst strength within a lightweight nonwoven sheet and produce highly uniform sheets with high green strength. Uniformity of the microfibers can allow for printability advantages, which adds value to specialty paper applications such as strong and lightweight backing for wall coverings and practical alternatives to high-strength polyethylene as a 100% Eastman Cyphrex sheet, the company says. 

More information is available online.