ZINC FACTS

Proper Name: Zinc Dialkyl Dithiophosphates

• A family of additives – not a single additive
• Polar molecule – attracted to steel
• Activated by heat and load

Types – High and Low Molecular weight

• Primary – more thermally stable (Slower “burn”)
• Secondary – less thermally stable (Faster “burn”)
• Aryl
• Lower Molecular weight – Less thermally stable

Developed in 1941
Limited By API – ISLAC Standards

• Began in 1992 – API SH/ILSAC GF-1 – 1,200 ppm max
• Contains Phosphorus

Source: Automotive Lubricants Reference Book, SAE International