Slack Wax SPO (Spindle Oil)

About This Product

Slack Wax SPO, derived from the spindle oil distillate fraction of lubricating oil refining, is a semi-solid petroleum-derived hydrocarbon wax classified under CAS No. 64742-61-6. The term 'spindle oil' historically referred to light lubricating oils used in textile mill spindles and precision machinery — and the SPO grade inherits this designation as the wax fraction crystallised from that specific distillate cut. SPO sits as the second lightest grade in the LMO-SPO-MMO-DAO hierarchy, exhibiting a pale to light yellow colour on the ASTM D-1500 scale (maximum 1.5). The large-scale industrial production of SPO slack wax traces back to the mid-20th century, when rapid expansion of lubricating oil refinery capacity — particularly across Southeast Asia and the Middle East — created abundant byproduct wax streams requiring systematic grading and commercial outlets. Pertamina's Cilacap refinery formalised the SPO classification as part of its product portfolio, a system since adopted as a de facto standard across global slack wax trade. With a melting point of 53–58°C and Bio Green Wax's customised oil content range of 5–20%, Slack Wax SPO offers a distinctly softer, more unctuous character than LMO while retaining useful wax structure for a wide range of processing applications. Its viscosity of 4.7–5.7 cSt at 100°C ensures reliable melt flow. An interesting fact: SPO is one of the most widely traded slack wax grades globally due to its broad application compatibility — effective in both light applications such as polishes and matches, and heavier uses such as fiberboard treatment and emulsion bases. Industrial applications include candle manufacturing as a blending and base wax, match and firelighter production, MDF, particleboard, and perforated board waterproofing, shoe and leather polish formulations, corrugated board moisture-barrier treatment, emulsifying wax (E-wax) production as a primary feedstock, general-purpose wax emulsion manufacturing, and tyre and rubber compounding.