microfiber size, shape, material, capabilities SizeMaterialShape
For more information about Eastman Cyphrex™ microfibers, contact us.

Change size. Change shape. Change material.

Eastman Cyphrex™ microfibers are changing everything.

To satisfy demanding and ever-increasing performance needs, Eastman Cyphrex™ microfibers are designed to target unique functionality by independently or simultaneously fine-tuning:

microfiber size
microfiber shape
microfiber material

Eastman Cyphrex microfibers help manufacturers of nonwoven media achieve desired functional properties with a completely new set of tools — all without forcing them to compromise performance in one area to make gains in another.

Exclusive innovations in Cyphrex technology and process allow Eastman to produce these easily dispersible synthetic microfibers in uniform and precise lengths, diameters and shapes.

Through leveraging its insight and capability, Eastman is positioned to offer Eastman Cyphrex microfibers that can make the most meaningful difference in nonwovens performance and substantially shorten the innovation cycle. With an understanding of critical performance requirements for specific wetlaid nonwoven applications, Eastman designs new microfibers targeted to satisfy those needs. In its fibers and nonwovens & specialty paper research labs, prototype fibers are developed, incorporated into nonwoven media, and evaluated to best understand their impact on critical parameters, such as porosity, permeability or strength.

Micro​fiber size

Eastman Cyphrex™ microfibers offer customers access to highly uniform fibers in previously unavailable lengths, diameters and cross sections.

By delivering microfibers below 0.4 denier in both round and flat cross-sections, Eastman Cyphrex™ microfibers offer access to high-specific-surface-area materials that are both highly uniform and easily dispersed. As a result, a range of desired functional properties can be achieved through blending different Eastman Cyphrex microfibers to achieve precise and repeatable nonwoven properties. For instance, you can pinpoint precise permeability, pore size, and strength.

For more information about how the various sizes of Eastman Cyphrex™ microfibers can enable differentiated nonwoven functionality,
contact us.


biocomponent fiber

​Microfiber​ shape


Eastman Cyphrex™ microfibers can be made in a variety of shapes, including round, flat, and wedge.

Eastman has conducted extensive research with round and flat microfibers to show how the properties of wetlaid nonwoven media can be fine-tuned to achieve targeted functionality.

Recently, Eastman introduced a flat PET microfiber that is less than 0.4 denier with a unique cross section that enables manufacturers to produce exceptionally uniform synthetic nonwovens that are lightweight and remarkably strong.

Cyphrex flat PET microfibers demonstrate that the microfiber shape can impact the attributes of wetlaid nonwovens in ways that changing microfiber size alone may not allow.

To learn more about the research Eastman is conducting on different shapes of Eastman Cyphrex™ microfibers, contact us.
wetlaid nonwoven
Microfiber material

Eastman Cyphrex™ microfibers allow expanded options for synthetic microfibers in wetlaid nonwoven media applications.

Eastman Cyphrex™ microfibers technology enables access to the widest range of synthetic polymers for microfibers. Eastman has the capability to leverage a broad set of polymers, from the most commonly used PET and PP to materials considered specialties for nonwovens, such as nylon, PLA, copolyesters, and others. Eastman uses this capability to target the right functionality for the right application.

For more information about research Eastman is conducting on microfiber materials, contact us.
Synthetic polymers, PET, PP, Nylon, PLA, nonwoven materials
microfiber porosity, permeability, nonwoven formulations
Possibilities for enhancing functionality

Eastman has conducted research to measure how varying Cyphrex microfiber size, shape, and material enable the creation of unique wetlaid nonwoven products with an endless array of formulations and performance advantages, such as pore size, permeability, formation, and strength.

Influencing substrate permeability

The ability to control the permeability of nonwoven media is critical in many high value applications — such as filtration. PET microfibers of discrete diameters and 1.5 mm in length were blended with NBSK pulp at levels of 20 and 40 wt% based on total furnish solids (Figure 1).

Not surprisingly, significant improvements in the permeability of the otherwise impermeable cellulosic sheet were observed, and those were seen to be directly related to both the diameter of the PET microfiber and the amount of microfiber present. What may be somewhat surprising is the relatively linear response with respect to microfiber diameter.

PET microfibers blend, diameter, permeability
blend two microfiber sizes, permeability

When you change size, precision is no small thing.

One might question whether the wide and useful range of permeability enabled by the 40% microfiber blends would necessarily require a number of fiber sizes to access that functionality. Figure 2 shows the discrete fiber diameters of Figure 1 replaced with a blend of two commercially available microfibers — specifically 2.5-micron and 4.5-micron diameters. Figure 2 shows how the apparent diameters created by blending these microfibers allow manufacturers to more precisely achieve targeted permeability properties.

Influencing substrate uniformity

The uniformity of a nonwoven media (aka “formation”) is an attribute of some importance, as it can influence a wide range of functional media characteristics, which can be negatively impacted by the non-uniformity of the substrate. These characteristics can range from relatively simple appearance requirements to rather complex filtration phenomena. Formation can be evaluated visually (by those sufficiently experienced) or instrumentally (e.g., M/K Systems, Inc., Formation Analyzer). The impact of PET microfibers of multiple sizes and shapes on the formation of a cellulose/synthetic blend was evaluated (see Figure 3).

While the 4.5 micron round Cyphrex microfiber significantly improves the formation when compared to a cellulosic blend, the flat Cyphrex microfiber delivers more than twice the improvement.

Nonwoven uniformity, PET microfibers, 1.5 mm length, cellulose synthetic blend formation
fiber diameter aspect ratio, formation, microfiber diameter, nonwoven formulations
tensile burst  nonwoven formulations
Changing shape changes strength

The hydrodynamic forming process for wetlaid nonwovens causes the flat cross-section of the flat Cyphrex microfibers to primarily orient with the wide side of the fibers parallel to the surface of the media. This phenomenon results in both a high fiber to fiber contact area for bonding and an exceptionally smooth surface without the need to calender the sheet. To demonstrate the strength benefit of the flat fibers, samples were prepared by increasing amounts of flat Cyphrex microfiber blended with 6 micron diameter, 6mm cut length round PET fiber and also with the 2.5 micron diameter, 1.5mm cut length round Cyphrex microfiber.

It is worth noting that the larger, non-Cyphrex, PET fiber could not be tested for strength at less than 25% flat Cyphrex microfiber because it lacked any detectable strength.

In addition to laboratory studies, continuous roll good sheets have been produced from 100% flat Cyphrex microfiber at various basis weights. Evaluation of tensile and burst strength on continuous media yielded surprisingly high results for binderless synthetic sheets (see table 1).

Unlock new possibilities with flat PET microfibers.

Eastman Cyphrex™ flat PET microfibers have a profile and aspect ratio that enable them to disperse easily in water — without special shear or agitation. By allowing a wider useful range of synthetic fiber content ratio than other commercially available synthetic microfibers, Cyphrex flat fibers are compatible with all standard wetlaid processes and equipment.

Learn more about how changing microfiber shape can improve formation and strength of nonwovens. For more information about the endless possibilities available with Eastman Cyphrex™ microfibers, contact us