Long chain polyamides like Rilsan® PA11 and Rilsamid® PA12 resins have been used to produce plastic fuel lines for more than 60 years because of their combination of high flexibility, excellent mechanical performance, and outstanding chemical resistance (to fuel but also to metal chlorides used in road salts). Successive regulations have made it mandatory to use barrier layers for gasoline and to introduce biobased content in fuels, which has generated new challenges for fuel lines.
Key application challenges:
- Adhesion with various barrier layers that can be used: Arkema has tremendous know-how in making resins with different polarity stick together and is the only material producer on the market to offer structural tie layers (Rilsan® Tieflex, based on PA6 or PA610) that allow optimized cost-performance balance multilayer constructions.
- Cleanliness of fuel in order to avoid clogging of sensitive line components like injectors: low oligomer releasing materials have been offered for several years (Rilsan® PA11 and more recently Rilsan® Tieflex, Rilsan® T PA1010) and low extractible materials are now available, to comply with most severe requirements on the market.
- Increasing environment temperatures: Engines are getting more efficient & under-the-hood space is decreasing but turning back to heavy & expensive rubber solutions is not mandatory. Rilsan® T PA1010 offers improved long term heat resistance vs PA12 & a higher high temperature burst pressure (thus safety factor) especially when combined with structural PA610-based Rilsan® Tieflex.
|Standard PA12 construction when no permeability resistance is required|
|Standard PA12 construction with good permeability resistance (EVOH)|
|Higher performance PA12-EVOH construction (VW specification) with excellent external ZnCl2 resistance & low oligomer content|
|High performance EVOH construction (VW, high temperature PA1010) with excellent external ZnCl2 resistance & low oligomer content|
|High performance EVOH construction (VW, high temperature PA1010) with excellent ZnCl2 resistance on all thickness & low oligomer content|
|High performance EVOH construction (VW, high temperature PA1010) with excellent ZnCl2 resistance on all thickness & low washout (extractible) content|
Rilsan® BESN black P20 TL (PA11)
& Rilsan® TESN black P213 (PA1010)
|Widely used in contact with most internal barriers on the market, especially in Japan|
- *All constructions have a conductive version when needed.
Diesel & Bio Diesel
Key application challenges:
- Increasing environment temperatures: Engines are getting more efficient & under-the-hood space is decreasing but turning back to heavy & expensive rubber solutions is not mandatory. Rilsan® T PA1010 offers improved long term heat resistance vs PA12 & higher high temperature burst pressure (thus safety factor) especially when combined with structural PA610-based Rilsan® Tieflex.
- Chemical resistance in contact with biodiesel: Aggressiveness due to methyl ester degradation, especially when produced from soy bean, requires more and more a switch from standard PA12 to better resisting solutions (Rilsan® PA11 and more recently Rilsan® T PA1010).
|Rilsamid® AESN black P201 TL||Standard PA12 solution|
|Rilsan® BESN black P20 TL||PA11 solution, for higher cold impact & thermochemical (biodiesel) resistance|
|Rilsan® BESN black P210 TL||PA11 solution with extreme cold impact performance|
|Rilsan® TESN black P213 TL||PA1010 solution with extreme cold impact performance, excellent resistance to biodiesel & improved thermal behavior (burst & long term)|
|Rilsan® BESN black P126 TL||PA11 solution with extreme performances (cold impact, thermal & chemical resistance)|
Fuel delivery modules require tubing that combine outstanding flexibility with resistance to extreme conditions like high temperature during tank production when in metal, and internal/external fuel contact. Good processability is also needed so that either smooth or corrugated tubes can be made to be .
|Rilsamid® AESNO P40 TL||Very flexible & natural colored PA12 solution|
|Rilsan® BESNO P40 TL||Very flexible & natural colored PA11 solution with better performances (cold impact, thermal & chemical resistance)|
|Rilsan® Evolution ENO P210 TL||Flexible & natural colored PA11-based alloy with extreme performances of thermal & chemical resistance|
Venting Lines & Fuel Filler Necks
Environmental regulations are making it mandatory to continuously handle more gases. This includes areas around the fuel tank and across the whole vehicle, which has led to the increasing quantity and diameter of venting lines. Arkema monowall and multilayer solutions for fuel lines and in-tank lines are well adapted for extrusion up to a diameter of at least 30 mm and corrugation is possible when a more flexible line is needed.
Replacing metal-rubber filler necks with plastic is also a growing trend to save weight and avoid corrosion issues that metal brings. The outstanding combination of performance and processability (extrusion, blow molding) of Arkema resins make it possible to produce parts according to the most challenging designs.
Conductive Solutions Available
Non-conductive fuel lines can create charge separation that leads to the build-up of electrostatic charges. This may create a serious safety concern for spark discharge, therefore a solution using conductive plastics may be preferred in the fuel delivery system.
- Rilsamid® AESN black P212 CTL – PA12 extrusion grade
- Rilsan® BESN black P212 CTL – PA11 extrusion grade
- Rilsan® ASR13 – PA12 injection grade
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