Rhodia Engineering Plastics provides a new polyamide solution to meet engine cooling circuits trends, Launching two TECHNYL® grades of unequalled resistance to time and temperature in a water-glycol environment

Rhodia Engineering Plastics is launching two new high-performance, glass filled TECHNYL® PA 66 grades: TECHNYL® A 218G1 V30 black 34N and A 218G2 V30 black 34N, for 30 % glass fiber reinforced; TECHNYL® A 218G1 V25 black 34N and A 218G2 V25, for 25 % glass fiber reinforced.

These two grades have been specifically designed for applications in cooling radiator water tanks and other parts in automotive cooling and heating circuits. Rhodia developed the new materials to give unparalleled resistance to the action of water/glycol, and also to respond to sharp temperature increases in such parts. The new grades will withstand a continuous temperature of 130°C, and will handle peak temperatures of 160°C. We focus on 30% glass fiber filled materials, according 25% glass fiber filled materials have the same behavior.

In the course of the developing the new resins, Rhodia’s research and development team identified that most typical under-bonnet grades of PA 66 showed a major decline in properties with usage: For a typical nylon component, at a temperature of 132°C and pressure of 2 bar, the retention of impact resistance after 700 hours’ ageing in a water-glycol environment was no more than 20% of the initial properties. By contrast, Rhodia’s new TECHNYL® A218G2 V30 grade succeeded in doubling that performance to 40%, and TECHNYL® A218G1 V30 black 34N also now gives the automotive sector an intermediary level of characteristics which is sufficient for certain specifications. Rhodia’s new automotive resins have also increased the load period - by 50% in the case of the TECHNYL® A218G1 V30 grade, and by 100% for the TECHNYL® A218G2 V30 grade.

The new material grades have been designed to absorb the high thermo-mechanical stresses, such as coolant pressure pulses, typical of most modern automotive cooling circuits. The mechanical strength of the new grades is consequently reflected in their stress and elongation performance on tensile break: TECHNYL A 218G1 V30 black 34N allows for an increase of 20-25% in this stress after a period of 960 hours at 130°C in a 50/50 water-glycol environment. TECHNYL® A 218G2 V30 black 34N allows for an increase of 40-50% within this parameter.

Rhodia also ensured that the new materials would respond to the most critical cases of vehicle function, where exceptional temperatures such as 160°C were reached over short periods.

Under such severe conditions, the new A218G2 V30 grade succeeded in retaining its initial impact characteristics, while those of a standard product declined by 50%.

Rhodia testing also showed that crazing and cracking were notably visible on standard products following chemical attack by glycol. In contrast, the surface of TECHNYL® A218G2 V30, for example, was unimpaired.

In Rhodia’s automotive product development, many market applications other than the side-cooling and heating radiator boxes were discovered: In fact, all elements of a modern automotive cooling circuit can be moulded in Rhodia’s new grades. These include: degassing boxes, gas oil/water or oil/water exchanger housing; the components mounted on the engine block and on the cylinder head (thermostatic housing, water inlet and outlet pipe); the water pump housings and water conduits.

The new engineering resins result from several years of dedicated polymeric research carried out by the laboratories of RHODIA ENGINEERING PLASTICS based in Ceriano (Milan, Italy). The heart of the materials research focused on a specific family of stabilizers, and the initial studies were conducted on test pieces that were monitored for autoclave pressure and temperature throughout the ageing period. Confirmatory tests were performed on components in Rhodia’s application laboratories based in Lyons, France and Freiburg, Germany. These latter tests were mainly to validate the temperature-cycled pressure resistance for the main applications for the resins.

Rhodia’s new grades are an example of the company’s global approach; founded on servicing the expectations of its automotive suppliers and the au

Reader enquiries