New Development


The world first Polyester Nanofiber
improve mechanical property
in rubber mixing


The fiber reinforcement effect in rubber depends on the aspect ratio of the fiber, defined as the ratio of its diameter to length. Reducing fiber diameter effectively increases the aspect ratio, but achieving good dispersion with fine fibers in high-viscosity rubber can be challenging. Consequently, thick, high-tenacity fibers are typically preferred in such applications. We have successfully developed very fine polyester fibers that disperse easily in rubber.
nanofront logo
(fiber diameter:700nm)

(fiber diameter:2μm)


In an island-sea cross-section, these fine fibers constitute the “island” within a “sea” of polyethylene polymer. By mixing the sea-island cross-section fiber with rubber at temperatures above the melting point of polyethylene (PE), the PE sea component melts and becomes compatible with the rubber. This allows for effective dispersion of numerous fine fibers within the rubber matrix, resulting in improved rubber properties, including enhanced modulus, vibration resistance, and flex resistance.
Work as dispersing agent in rubber

Diamter & Length Numbers of Fibers Aspect Ratio
400nm x 0.5mm 25,000 1,250
700nm x 1m 4,080 1,429
20pm x 5mm
1 250

Conventional Fiber in Rubber

Nanofront® 700nμ×1mm in Rubber


Our Products Polyester Cut Fiber Aramid Cut Fiber
400nμ Nano Fiber 700nμ Nano Fiber

Cuttable length :0.5mm~

“Observation of Dispersion State and Tensile Fracture Surface Using Electron Microscopy

Conventional Material 3% Added 400nm 10% Added 700nμ 3% Added 700nμ 10% Added
x 1000
x 2000

Cross-section of the rubber compounding sheet

PE (sea components) is compatible with rubber, and PET nanofibers disperse well within the rubber

How it works



Ultra Fine Polyester Fiber Conventional Short Fibers
  • Achieving unifrom disperson within rubber by heating above 130℃ to melt the Sea component(PE).
  • The rubber and fine fibers undergo a process akin to merging and stretching together, commonly referred to as Parallel mode deformation
  • Parallel mode deformation, combined with a large aspect ration, results in a higher modulus even with a small quantity of fine fibers in the mixture.
This represents a straight model where rubber (the matrix) and fibers deform separately. In this model, the softer rubber deforms first, and it’s less prone to experiencing stress increases.

Parallel Model

Rubber and fine fibers integrate, Requiring a consider force for deformation

Straight Model

Rubber part is easily stretched with small stress


Streamlined manufacturing process helps reducing the amount of chemicals and water consumption. The energy required to product PE/PET Nano reinforcement fiber could be roughly estimated to be half that of conventional fibers. (in house comparison)
Conventional reinforcement fiber Solid polymerization
Surface Treatment
Kneading with ruber
Increasing molecular weight Adhensive agent for rubber
(ref.) Cellulose nano fibers Mechanical Refining
Water based slurry
Replacing water to organic solvent
Kneading with ruber
PE/PET nano reinforcement fiber
Kneading with ruber


Transmission Belts

  • Driving Stability and Longer Life is Essential performance for belts.
  • Make it possible with Nanofront

Our Solutions

① Driving stability (energy-saving, safety)
: proportional to modulus
  1. 1.Increasing Modulus
  2. 2.Improves Driving Stability
  3. 3.Energy saving and enhancing Safety
② Durability (Long life ・safety)
: proportional to flex durability
  1. 1.Increasing Flex Durability
  2. 2.Improves Product Durability
  3. 3.Extended life and enhancing Safety


    Rubber containing nano PET fibers exhibits a low tanδ value at 60°C, which makes it a promising material for use in tires with reduced fuel consumption.

Tan δ at 60℃ represents Low Rolling resistance of tire

EPDM+nano PET fiber 700nm* 3parts
EPDM+Aramid 3parts
tan EPDM EPDM PET diameter of
700nm × 1mm × 3parts
EDPM Conventional
Aramid × 3mm × 3parts
60℃ 0.25 0.189 0.241

Vibration Isolator

Dynamic Multiplication =
Dynamic spring constant
= Absorbance of vibration
Static Spring Constant
= Supportive Property

Dynamic & Static spring constant and Dynamic multiplication