CFF® Fibrillated Fiber

CFF® acrylic pulps offer a number of unique advantages in specialty wet laid and slurry applications. CFF fibrillated fibers were developed to serve as high-efficiency binders in addition to providing other engineering attributes to technical papers, filter media, nonwovens, speaker cones, pulp molded products and specialty composites.

CFF fiber

Figure 1: CFF Fibrillated Fiber Structure.

CFF fibrillated fiber pulp is produced by unique technology incorporating a special grade wet spun acrylic fiber precursor, and is fibrillated in a customized refining process. The architecture of the pulp, which is obtained by controlling the combinations of fiber length and degree of fibrillation, distinguishes CFF as a uniquely engineered fiber.

As shown in Figure 1, CFF fibrillated fiber has a treelike structure with a main fiber and various size limbs and branches attached to the main trunk. The trunk fiber is about 20 µm in diameter, with smaller macro-fibrils and fibrils with diamters down to a few µm. Very fine micro-fibrils which are ~1 µm in size can be created with sufficient processing, which is unique for a synthetic pulp.

CFF pulp provides both the very high degree of fibrillation and the fiber length required for high-performance nonwoven and specialty composite applications. This long, highly fibrillated fiber cannot be achieved with conventional refining techniques traditionally used with standard acrylic fibers. A comparison of processes is shown in Figure 2.

fiber length vs binding capacity

Figure 2: Structure-property map for conventional and CFF acrylic pulps.

CFF wet pulps are being used in wet laid paper processes for interlocking other organic and inorganic fibers as well as various powders, such as aramid, carbon, etc. CFF 106-3 pulp has a Canadian Standard Freeness (CSF) of 600 ml and a typical length of 6.5 mm. CFF 111-3 pulp has a CSF of about 250 ml and a typical length of 6.5 mm. CFF 114-3 pulp has a freeness of 60 ml and a length of about 4.3 mm. These materials are supplied at about thirty percent solids and are available in commercial quantities. CFF 125-2 has a smaller trunk diameter and shorter length for improved dispersion in low intensity hydropulpers. Other freenesses between 650 and 50 ml can also be supplied. CFF wet pulps contain no size or surface finish.

Commercially available grades of CFF acrylic pulp.
CFF Pulp TypeSolids Content
(%)
CSF
(mL)
Typical/Max Fiber Length
(mm)
106-3306006.5 / 8.0
111-32506.5 / 8.0
114-3604.3 / 6.0
125-2504003.5 / 5.5

Typical Properties of CFF Fibrillated Acrylic Fibers

PropertyUnitValue
Densityg/cm31.17
Tensile StrengthMPa450
ModulusGPa6.0
Elongation%15
Typical Fiber Lengthmm4.5 - 6.5
Canadian Standard FreenessmL35 - 700
BET Surface Aream2/g50
Moisture Regain%<2
Surface Charge Anionic
Appearance Fine white pulp

Applications of CFF Acrylic Pulp

CFF Fibrillated Fiber in Specialty Papers

One hundred percent acrylic papers with a wide range of properties can be produced utilizing acrylic pulp alone or in combination with acrylic staple to produce an entirely synthetic paper with controlled sheet characteristics. The tensile strengths of acrylic sheets prepared from various blends of staple and pulp are shown in Figure 3. These physical properties are for binder-free one hundred percent synthetic fiber paper made from combinations of fibrillated fiber and acrylic staple without the use of any resins, adhesives, chemicals, additives, or any heat calendaring.

tensile strength increase with CFF

Figure 3: Tensile strength of acrylic-based papers.

Use of one hundred percent acrylic paper has advantages of exceptional wet strength, moisture resistance, dimensional stability at varying humidities, resistance to sunlight (UV), and excellent chemical resistance, to name a few. There is little difference in dry or wet sheet strength because the fibrillated fibers are mechanically entangled during drying and the fibers are then relatively insensitive to moisture. By choosing the proper degree of fibrillation of the acrylic pulp and the proper manufacturing procedure, filter paper consisting of one hundred percent fibrillated fiber can be made for the whole range of analytical filter paper requirements established for cellulosic paper. Filter paper produced from these fibers has excellent acid resistance, good alkali resistance and is insoluble in common organic solvents.

CFF Fibrillated Fiber in Filtration Media

Nonwoven filtration media can be produced without resin binders by utilizing fibrillated fiber to mechanically interlock all components of the sheet, including organic and inorganic fibers, granulars and fine powders. The use of fibrillated fiber permits the incorporation of materials not normally used in non-woven form, such as activated carbon fibers and powders.

Fibrillated acrylic pulp is also attractive for use in aerosol and HEPA filters where glass microfibers are normally used, since the fibril size of the acrylic may range to near micron or sub-micron size. Incorporation of acrylic pulp into papers containing glass microfibers has been shown to reduce shredding and improve strength. For aerosol entrapment, it is possible to make paper using one hundred percent CFF fibrillated fiber which has high DOP resistance while maintaining acceptable air flow.

CFF Fibrillated Fiber in Speaker Cones

CFF acrylic pulp is now being used by several speaker cone companies worldwide on a commercial basis in their slurry molding processes. Typically about 20-30 percent of CFF pulp is used either with cellulose pulps or a blend of cellulosic pulps and glass or other short synthetic fibers. These acrylic pulps enhance physical and mechanical performance, provide better acoustical / frequency response, reduce moisture adsorption, and improve wet strength. Cones containing CFF acrylic pulp can be hot pressed to improve surface smoothness, increase strength and reduce porosity. CFF 111-3 is the most commonly used pulp because of its good balance of properties.

Data Sheet:

Other Fibrillated Fibers: