Tribasic Lead Sulphate is the most versatile and most popular Lead stabiliser for PVC, specially for high temperature working. It is by itself very stable to heat and can be heated,without fear of decomposition, to temperatures higher than those normally encountered in PVC compounding and fabrication such as high speed extrusion and manufacture of PVC rigid products. Sound products with complete absence of porosity caused by gas evolution are thus ensured. Very good electrical properties are also imparted to the compound when stabilised with TBLS. It is white, sweet and toxic powder with specific gravity of 7.10. It can dissolve in nitric acid, hot thick hydrochloric acid, ammonium acetate and sodium acetate, partly in acetic acid, but not in water. It will become yellow when it loses water of crystallisation at 135.

Tribasic Lead Sulphate is well known for its excellent stabilising properties in the PVC. Balsochem TBLS has been given a special surface coating to ensure its higher and better dispersion, irrespective of the compounding techniques. It is highly suitable for all types of pigmented compounds requiring heat stability over longer periods, particularly for rigid or unplasticised extrusion of rain water pipes, guttering soil pipes and pipes for carrying gases and liquids. It is also recommended for use in PVC compounds for fabrication of injection moulding items like elbows, bends etc. When used in mixture with Dibasic Lead Phosphite, it provides excellent weathering properties, since DBL Phosphite is resistant to ultra-violet light. Since it has good electrical properties, it is widely used for cable sheathing. It's very good electrical properties have high values of volume and surface resistivity. Being non-lubricating, it benefits by the addition of a small amount of a stabiliser lubricant such as Lead Stearate or Dibasic Lead Stearate. Combination of more than one lubricant in the desired production should be added to TBLS to take care of heating friction and sticking at feed mixing and shearing in the barrel zones of extruder and hot die temperature.