Hydrolysis resistance to hot water and steam as well as its resistance to environmental stress cracking when exposed to aggressive chemicals are two particular attributes of the 610 chemistry of polyamide (PA) that reportedly make it a worthy competitor to other long-chain high-performance polyamides such as PA 612 or PA 12. Further, it has a lower density and reduced moisture uptake compared with conventional PA 6 and 66.
BASF (Ludwigshafen, Germany) plans to release several new PA 610 grades at the K Show in October designated Ultramid S3EG6 Balance, Ultramid S3WG6 and S3WG7 Balance and Ultramid A3HG6 Balance. Their glass fiber contents are 30 (G6) and 35 (G7) percent and they will be available in sample quantities in Europe as of September.
Ultramid S3K Balance exhibits hydrolysis and stress crack resistance against chemicals like calcium chloride or zinc chloride.
One of the raw materials for production of Ultramid S Balance and Ultramid A Balance is sebacic acid, which is derived from castor oil. Thus, over 60 percent of the base polymer for the product family comes from renewable resources.
Above all, PA 610's resistance to calcium chloride, which is used in Asia and Russia as road salt, and zinc chloride, which can form on car bodies, should be emphasized according to BASF. Compared to PA 66, the material has not only greater dimensional stability, but also exhibits only a slight difference in mechanical properties between the dry and conditioned states. It is stronger, stiffer and has a higher heat deflection temperature than PA 12.
The three new grades in the Ultramid S Balance line are said to be especially well suited for overmolding of metal and electronic components that come into contact with aggressive fluids. They are also of interest for housings and transmission components where dimensional stability is a major factor. Connectors, tubing and reservoirs in coolant circuits that must satisfy demanding requirements for hydrolysis resistance represent an additional field of application. The material has already demonstrated its performance capability in wheel speed sensors that are exposed to water spray and can be attacked by road salt.
Ultramid A3HG6 Balance is a blend of PA 610 and PA 66 and characterized by a property profile that lies between that of PA 66 and Ultramid S Balance, while retaining its high resistance to environmental stress cracking and exhibiting in addition very good resistance to hot oil. This makes it a suitable candidate for oil pans and oil filter housings as well as for radiator end caps, wheel speed sensors, and other components subject to contact with aggressive water spray—in other words, for applications that do not have to satisfy the most demanding requirements for resistance to hot water, but must be strong, stiff, and dimensionally stable at elevated temperatures. —Stephen Moore