Fibrillated fiber is the general term used for fibers that have been subjected to a proprietary wet fibrillation process. Fibrillation results in “peeling” of the surface of individual fibers into fibrils, and thus increasing the surface area by generating highly branched fibril structures. Fibrillated fibers can be used to make specialty papers, or in applications where a high degree of mechanical entanglement is desired, such as in high-performance filtration media.

The founders of Engineered Fibers Technology have been involved in fibrillating fibers for over 20 years, and have developed unique commercial and experimental fibrillation technologies to fibrillate a variety of different fibers, such as:

• Acrylic (CFF®)
• Lyocell (Tencel®)
• LCP (Vectran®)
• PBO (Zylon®)
• Para-aramid
• Cellulose (wood and non-wood)

 

Engineered Fibers Technology (EFT) has developed and is manufacturing a unique product line of nanofibers under the name EFTec™ Nanofibrillated Fibers, which are produced from a wide range of synthetic and natural (sustainable) materials. These fibrillated fibers have a broad distribution of fibril diameters covering a range between 50 to 500 nanometers, which is the same diameter range as that achieved with electrospinning and melt-spinning of nanofibers and nanofiber webs.

Depending on the Canadian Standard Freeness (CSF) levels,and precursor fiber lengths, there can be between 40 million and 200 billion nanofibers /gram of dry fiber. As a comparison, eucalyptus pulp, used in papermaking to make products requiring fine fibers, would have about 14 million fibers per gram. Nanofibrillated fibers can be as small as 0.1-0.25 microns in diameter, which translates to 0.1-0.7 mg/ 9000 m or 1-7x10^-4 denier. For comparison, the starting precursor fibers are 1.5 denier (1.5 g / 9000 m) and have diameters of 11-12 microns.

In addition to fibrillated nanofibrils, EFTec™ Nanofibrillated Fibers also contain a small number of  residual longer precursor fibers that function as scaffolds and enable the bridging of the nanofibrils.

By using EFTec™ Nanofibrillated Fibers, one can dramatically increase fiber number concentration at relatively low addition rates. Precursor fiber length, which is typically in the range between 3 and 6mm can be selected based on a specific application. The fiber length of the fibrils may also depend on the starting length and the degree of refining during the fibrillation process. The unique EFTec™ manufacturing process does not result in fiber cutting, which allows one to preserve the length of fibrils at the same level as that of the precursor fiber. However, a specialized process can be employed if there is a need to shorten the fibers to less than 1 mm, as may be desirable in some applications, such as e.g. coatings.

EFTec™ Nanofibrillated Fibers are suitable for use in papermaking, for making wet-laid composites and in other processes used to manufacture many types of slurry-processed or molded engineered materials.   

EFTec™ Nanofibrillated Fibers address many of the disadvantages existing with other nanofiber materials. Proprietary EFTec™process yields smaller diameter microfibers, as compared to those obtainable with melt-spun fibers, including splittable bicomponent fibers known as "islands in the sea".  EFTec™ Nanofibrillated Fibers typically have high aspect ratios over 1000 and are produced economically in metric tons per day quantities. The latter allows one to broaden value proposition and utilize these nanofibers in materials and applications for which the use of both electrospun and meltspun nanofibers is not viable because of availability and cost.   EFTec™ Nanofibrillated Fibers are utilized in large volume applications, such as specialty / technical papermaking, as well as manufacturing of high efficiency filtration media, consumer wipes /wipers, battery separators, electrical insulation papers, and building materials. EFTec™ Nanofibrillated Fibers work just like nanofibers in existing applications but without such limitations as the need to apply them as a layer onto another material, or to produce a nonwoven web. EFTec™ Nanofibrillated Fibers can be blended directly as a component into the furnish for making wet laid papers.

EFTec™ Nanofibrillated Fibers improve and enhance properties of cellulosic paper products. They act as mechanical binders in papers to effectively hold fillers such as calcium carbonate, talc, clay, etc. In typical wet laid papers these nanofibers significantly increase wet web toughness and increase wet strength.  The inclusion of these materials into graphic papers or into paper coatings changes the substrate microstructure, so that the inks stay on the surface and yield much more vibrant yellow and red colors that are difficult to achieve otherwise. The utilization of these nanofibers also significantly increases sheet opacity, surface smoothness and bulk of the paper. For example, higher opacity/ higher bulk papers with smooth surfaces for extremely bright and clear photographic papers can be made without chemical additives and coatings.

EFTec™ Nanofibrillated Fibers can be utilized to control and enhance porosity, and are currently used in microfiltration papers for potable water to achieve specific pore sizes, in automotive, and analytical filters to improve efficiency by producing  papers with extremely tight submicron pores, and in wet friction (transmission) papers to control fluid flow. The tight pore structure having mean pore diameters on the order of tenths of a micron can be achieved.  EFTec^TM Nanofibrillated Fibers, when added or coated onto fabrics and papers, allow one to produce materials with significant barrier properties and controlled porosity.  The end applications for such materials can be very diverse and include medical barrier materials, environmental protective clothing, fuel cells, barrier packaging, etc. Because of small diameters and high aspect ratios of these fibers, the materials with very low basis weight / caliper (<10 g/m2 / 25 micron) and very low mean pore diameters can be produced and utilized in  such applications as membranes, and battery separators.


EFTec™ Nanofibrillated Fibers and can be carbonized in paper form  Both Lyocell (regenerated cellulose) and acrylic (PAN) can be carbonized (with or without chemical treatments increasing char yields) after being formed into paper. The use of carbonized materials have been evaluated for use in ultracapacitors and other electrical storage devices.

EFTec™ Nanofibrillated Fibers are economically produced in large commercial quantities. The ability to produce EFTec™ ffibers on a commercial scale offers the companies developing nanofiber-based products an opportunity to evaluate them for large volume applications, focusing on adding value and delivering new product features without worrying about supply issues.

CHARACTERISTIC DIMENSIONS	Diameter (nm)
Atom	0.03 - 0.3
Electrospun Nanofibers	50 - 500
EFTec™ Nanofibrils	100 - 500
Melt Blown Microfibers	2,000 - 5,000
Blood Cell	2,000
Carbon Fiber	7,000
Textile Fiber (1.5 Denier)	12,500
Human Hair	30,000

EFTec™ Nanofibrillated Fibers can be effectively dispersed in water and used with various wet-laid paper machines  to obtain specialty nonwovens or papers. In order to obtain maximum performance, the starting wet lap needs to be dispersed and the nano-fibrils need to be opened up at the initial stages of use. The extent of dewatering and compaction in the produced EFTec™ Nanofibrillated Fibers is controlled to permit good dispersion in typical high shear environment existing in hydrapulpers, refiners, beaters, etc. EFTec™ pulps can be successfully processed on Fourdrinier, Roto-former, Inclined Wire and Cylinder paper machines, as well as pulp molding machines.

Regardless oof the type and concentration of EFTec™ Nanofibrillated Fibers used, they can be readily dispersed and formed in sheet making equipment using EFT recommended industrial best-practice procedures. However, one must remember that material quality can be affected by several factors including storage conditions, moisture levels, type of paper machine, degree of fibrillation, dispersion, and the use of specialty chemicals, such as retention, dispersion or drainage aids.

AVAILABLILITY
 
EFTec™ Nanofibrillated Fibers are available in a range of standard grades, either as a wet lap / wet crumb (about 20% solids) or as an aqueous slurry (<5% solids). Three types of precursor material are available, and all types can be produced with different precursor fiber lengths and different degrees of fibrillation. All grades are being produced on a commercial scale and can be delivered in truck-load /container load quantities, as well as in smaller-scale / production quantities

EFTec™ Nanofibrillated Fibers: Standard Types / Designations

EFTec™ NANOFIBRILLATED FIBER	PRECURSOR FIBER	DEGREE OF FIBRILLATION, CSF* (mL)	SOLIDS (% by wt.)	PRECURSOR FIBER LENGTH mm
L-010-4	Lyocell - 1.5 denier	10 ± 5	25 ± 7	4.0 ± 0.2
L-040-6	Lyocell - 1.5 denier	40 ± 12	25 ± 7	6.0 ± 0.2
L-115-6	Lyocell – 1.5 denier	115 ± 15	25 ± 7	6.0 ± 0.2
A-010-4	Acrylic – 3.0 denier	10 ± 5	25 ± 7	4.0 ± 0.2

*CSF=Canadian Standard Freeness

PRODUCT CODES EXPLAINED           L-040-6 is Lyocell Fiber, 40 mL CSF, 6mm Precursor Fiber Length             A-010-4 is Acrylic Fiber, 10 ml CSF,4mm Precursor Fiber Length

EFT can acan also manufacture customer-specific grades of nanofibrillated fibers with specific lengths of precursor fibers and fibrillation levels where required. Such EFTec™ Nanofibrillated Fibers are also provided as a dewatered wet lap or wet crumb with approximately twenty (20) percent solids content.

TECHNICAL / QUALITY SUPPORT

Engineered Fibers Technology has a commitment to quality and to provide technical and engineering support  to assist customers in the use of EFTec^TM Nanofibrillated Fibers. All EFTec™ products are manufactured to closely defined specifications and quality standards. Certifications are included with all shipments. Our Development Laboratory in Rockford, IL is available to provide additional information, technical assistance and contract-based product development to address specific customer needs,

Nanofiber Definitions
Exact definition of the term "nanofibers" is still a subject of continuing discussions. ISO Technical Committee TC 229 on Nanotechnologies is in charge of developing standards for "understanding and control of matter and processes at the nanoscale, typically, but not exclusively, below 100 nanometers in one or more dimensions".* This definition most closely describes very short (0.1 mm or less), highly crystalline, needle-like “nanocellulose” fibers extracted from wood pulp. These fibers have high modulus which makes them suitable for use in composites reinforcement. Most nonwovens manufacturers dealing with fibers generally understand that the term “nanofiber” generally relates to fibers with diameters of less than 1000 nanometers (1micron, µm), and preferably less than 0.5 µm , with much longer lengths (high aspect ratios). EFTec™  Nanofibrillated Fiber products conform to these definitions.

*International Organization for Standardization, Technical Committee TC 229. 2005. Scope.
https://www.iso.org/committee/381983.html