Exfola™

Surface Modifier

Usage detail

Exfola™ is an additive for polyolefin, such as polyethylene and polypropylene, and combines the characteristics both of polyolefin and silicone.

Usage
Characteristic

Oil resistance

  • Introduction
  • Characteristics
  • Applications

Exfola™ is an additive for polyolefin, such as polyethylene (PE) and polypropylene (PP), that combines the characteristics of polyolefin and silicone. Exfola™ is most often used as a surface modifier for injection molded parts, or extruded articles and film. Enhanced surface properties include:

  • Releasability
  • Water Repellency
  • Oil Repellency
  • Lower Coefficient of Friction
  • Abrasion Resistance
  • Surface Smoothness

Exfola™ is widely used as a surface modifier of polyolefin film, sheet, containers, and packages. The product is available in pellet form, and in two types:

  • Polyethylene-based (PE) Masterbatch
  • Polypropylene-based (PP) Masterbatch

Block Polymer of Polyolefin and Silicone Units

Exfola™ is a genuine tri-block polymer in which polyethylene (PE) units and the silicone unit are combined by covalent bonds. The PE block of Exfola™ ensures compatibility in either a polyethylene-based (PE) or polypropylene-based (PP) masterbatch.

The proper selection of either PE-based masterbatch or PP-based masterbatch enables Exfola™ to bond exceptionally well with injection molded polyolefin parts, and with extruded articles and films. The silicone block allows Exfola™ to offer astonishing surface modifications including oil and water repellency, low coefficient of friction, and “releasable film” properties.

Exfola™ is a tri-block copolymer consisting of Silicones and polyethylene (PE) units. The pelletized product is opaque white in appearance, and offers very low specific gravity at 0.963 gm/ml. The polyethylene block allows Exfola™ to bond with polyolefins; polyethylene (PE), polypropylene (PP), polybutene (PB) and thermoplastic polyolefin (TPO) resins. The Silicone block modifies the surface properties of injection molded parts or extruded articles.

Unique Features of Exfola™

Exfola™ is valued for its ability to modify the surface properties of injection molded parts and extruded articles. The unique features of Exfola™ include:

  • Excellent compatibility with polyolefins, from the Exfola™ polyethylene block
  • Outstanding Oil / Water Repellency from the Exfola™ silicone block
  • Exceptional “slippery properties” from the Exfola™ silicone block

The oil and water repellency properties offered by Exfola™ may be demonstrated by Surface Free Energy measurement. The addition of 10% Exfola™ to homopolymer polypropylene, and to EVA reduced the measured Surface Free Energy to levels approaching that of PTFE.

The “slippery properties” offered by Exfola™ may be demonstrated by Coefficient of Dynamic Friction (COF) measurement. The addition of 10% Exfola™ to homopolymer polypropylene reduced the measured COF by nearly 70%.

As a tri-block copolymer, Exfola™ demonstrates excellent compatibility with a polyolefin substrate due to its polyolefin block, while altering surface properties due to its Silicone block. These attributes create value in release film and flexible packaging applications, as well as industrial wear-resistant articles.

Polypropylene Release Film

Exfola™ was added to polypropylene (PP) film, and peel strength was measured against an acrylic adhesive layer. The addition of 15% Exfola™ on polypropylene film yielded peel strength below that of silicone coated PET film.

The demonstrated improvement in releasability finds application in adhesive protective film that requires easy-release on its back side. The potential to replace silicone coating processes with Exfola™ offers economic and sustainability benefits in release film applications.

Due to its polyethylene (PE) block, Exfola™ demonstrates excellent compatibility with polyolefins. As a result, Exfola™ additivated articles or films offer minimal silicone transfer or bleed out, compared to silicone coating. This makes Exfola™ an outstanding choice for applications requiring high surface purity.

Oil Repellency

Cooking oil colored with black ink was poured into heat-sealed flexible packages. The packages were constructed with 2-layer polypropylene (PP) film. The inner layer was 5 microns thick, and the outer layer was 45 microns thick. The packages were vigorously shaken for two minutes, and movement of the liquid was observed.

Two versions of the 2-layer package were produced. One version was constructed with 10% Exfola™ in the 5-micron polypropylene (PP) inner layer. The second version was constructed with no Exfola™ in the inner layer. Cooking oil was observed clinging to the inner surface of the 2-layer PP film packages made without Exfola™. Dramatic improvement was seen in the package made with Exfola™.

The results indicate Exfola™ can demonstrate value in flexible packaging applications, as well as in rigid containers for cosmetics.

Wear Resistance

The addition of Exfola™ to polypropylene or polyethylene can significantly improve the wear resistance of injection molded parts, or extruded articles. Exfola™ was added to polypropylene (PP) injection molded disks at 3% and 10% loading. Wear resistance was measured by the rotation of a metal cylinder placed on the injection molded disks.

The wear resistance of injection molded polypropylene disks showed dramatic improvement with the addition of Exfola™. The results indicate Exfola™ can demonstrate improve wear resistance in syringe and spray pump applications.

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