AutoFocus #15, September 2011
DuPont™ Viton® fluoroelastomer enables new fuel hose by Ningbo TIP to meet Toyota emissions requirements

Ningbo TIP Automobile Parts Co. Ltd. of China, a leading supplier of rubber hose to major automobile makers, has chosen DuPont's patented co-extrusion technology, with a barrier veneer of DuPont&trade Viton® fluoroelastomer, to produce a fuel filler neck hose for Toyota Europe's Yaris, Avensis and Verso gasoline powered cars. The construction of FKM/NBR/Kevlar® aramid fiber/NBR offers processing and interlayer adhesion advantages and rugged durability, while the veneer of Viton® fluoroelastomer provides a barrier to permeation by aggressive fuels, enabling the filler neck hose to meet Toyota and global emissions requirements.

Low permeation and best adhesion
According to the Chief Engineer, Technical Development and Quality Control Director of Ningbo, the "low permeation of the FKM terpolymer compound, low volume swell in gasoline and diesel, adhesion with the NBR layer, easy extrusion and low temp flexibility" were key reasons for choosing Viton® in the special multi-layer construction.

He reports that the unique co-extrusion technology enables the best adhesion between DuPont&trade Viton® fluoroelastomer and PVC-containing NBR compounds. In addition, the reinforcing layer of DuPont™ Kevlar® aramid fiber gives the hose essential stiffness and strength to resist mechanical stresses during the lifetime of the vehicle.


The key veneer layer of DuPont&trade Viton® fluoroelastomer in this multi-layer fuel neck hose by Ningbo TIP for the Toyota Yaris, Avensis and Verso (seen here) provides resistance to gasoline and aggressive fuel additives, and a barrier to fuel permeation.


Cost advantages
Among key factors that influenced Ningbo's decision in favor of the patented construction were the material, processing and production efficiency advantages of the Viton® VTR-9217 compound, resulting in a competitive total cost benefit.

New development with a future
The co-extruded FKM/NBR/AR/NBR construction represents a new development for Ningbo and one that has a good future, the company reports. In addition to Toyota, the company is using the Viton® FKM-based construction in a program with Dongfeng Nissan.

About Viton®
DuPont&trade Viton® has been the elastomer of choice in seals and hoses for automotive fuel systems for nearly 50 years. It helps auto manufacturers meet tough LEV, PZEV and Euro 5/6 automotive evaporative emissions control legislation requirements by providing fuel system sealing capability for the lifetime of the vehicle, at operating temperatures well above 150°C, or as low as -40°C.

Viton® fluoroelastomer exhibits broad compatibility with, and excellent resistance to, petroleum-based fuels, and also to new flex fuel/alcohol/ether blends and biofuels. It also has the best permeation resistance of traditional elastomeric sealing materials, being 1000 times better than VMQ and 100 times better than HNBR.

About Ningbo TIP
Ningbo TIP Automobile Parts Co.Ltd., produces high quality molded and extruded automotive hose, including fuel, water, and air conditioning hoses, supplied to Dongfeng-Citroen, Dongfeng-Nissan, Ford, GM, Honda, Mazda, Toyota, and VW, and to Tier 1 manufacturers such as Bosch, John Deere, Denso and Kuboda. The company operates plants in Ninghai County and Shanghai Jinshan, China.

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