The Polyplastics Group has announced the introduction of a new polybutylene terephthalate (PBT) resin which delivers excellent alkali stress crack resistance for a range of automotive applications. The new grade, DURANEX(R) 532AR, also exhibits outstanding hydrolysis/heat shock resistance and electrical performance for components in the chassis and engine compartment.
As demand for durability, safety and reliability in auto parts continues to increase, DURANEX(R) 532AR has successfully reduced the risk of cracking in molded articles by preventing alkali from penetrating the inside of the resin, thus imparting toughness that helps generate less stress. This alkaline can arise from rust formation in metal parts. DURANEX(R) 532AR, treated with a hydrolysis-resistant formula, has greater durability than standard materials.
Recent test evaluations show that when specimens are immersed in alkali, cracking occurs within two hours in standard material DURANEX(R) 3300 and in hydrolysis- and heat shock-resistant DURANEX(R) 531HS. No stress cracking occurs in DURANEX(R) 532AR even when immersed for up to 200 hours.
Electrical components and sensors installed near the engine are also often metal insert-molded and there are cases when sudden temperature changes can cause heat shock fracture issues. This occurs because the metal and resin have linear expansion coefficients that differ by roughly a factor of 10. DURANEX(R) 532AR also has outstanding heat shock resistance and is capable of withstanding these harsh environments.
DURANEX(R) 532AR is ideal for use in parts installed in the chassis section and lower areas of vehicles which can be splashed with water and mud, and come into contact with chemicals such as snow-melting agents. This grade offers a combination of high reliability and long life even in harsh environments.
