New conductive low-extractable multilayer tubing system without fluoropolymer inner layer

25 October 2019 | Web Article Number: ME201916769

Chemical & Allied Industries
Plastics & Rubber

EVONIK Industries, Essen, a global supplier of polyamide 12 for multilayer plastic tubing systems, is expanding its product range to include the MLT 4840 multilayer tubing system, another low-extractable conductive system for fuel lines.

Its special feature is that the inner layer does not consist of a fluoropolymer but of a conductive low-extractable VESTAMID polyamide 612. “The system is therefore outstandingly well suited for extrusion. It shows excellent antistatic properties even after long-term contact with alcohol-containing fuels and is also more cost effective than systems with fluoropolymers. No comparable fuel line system currently on the world market has this particular combination of properties,” the company said in a statement.

Low-extractable plastics for fine injectors Alcohol-containing fuels, such as ethanol-containing biofuels, can dissolve out components from the inner walls of conventional fuel lines. Under certain extreme conditions, these substances could clog the nozzles in sensitive fuel systems that use small-diameter nozzles to create an atomized spray of fuel and air for fuel injection, in order to reduce fuel consumption.

To reliably exclude the possibility of clogging, Evonik has expanded its range of multilayer tubing systems to include some with significantly reduced extraction.

New conductive low-extractable multilayer tubing system without fluoropolymer inner layer

For many years now, MLT 7440 has been offering a conductive low-extractable system with an EVOH (ethylene vinyl alcohol) barrier layer and a fluoropolymer (EFEP) inner layer; thanks to its mechanical properties such as low-temperature impact strength, chemical resistance, and permeation behavior, the system is already being widely used globally. MLT 7400 is the nonconductive variant with the same layer structure.

In Europe multilayer tubing systems with an EVOH barrier layer and polyamide inner layers are most commonly used. MLT 4800 is a low-extractable system from Evonik with a low-extractable VESTAMID® polyamide 612 inner layer. This system has now been supplemented by the conductive variant with the same layer structure and an antistatic, low-extractable VESTAMID polyamide 612 inner layer.

“The combination of properties in the new MLT 4840 multilayer tubing system is a milestone in development,” said Dirk Heinrich, head of the Automotive & Mobility market segment of the High Performance Polymers business line.

“The system combines the easy processability of polyamides 12 and 612 with exceptionally low extraction values and stable conductivity even in the presence of alcohol-containing fuels, at attractive system costs. At present it is the only one of its kind on the market,” he said.

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