Slack Wax LMO (Light Machine Oil) — Frequently Asked Questions

Slack Wax LMO (Light Machine Oil) is a semi-solid petroleum-derived wax produced as a byproduct of the solvent dewaxing process during lubricating oil refining. It is the lightest grade in the slack wax family, composed of straight-chain and branched saturated hydrocarbons (CAS No. 64742-61-6) with carbon numbers predominantly in the C20–C50 range. LMO is characterised by a near water-white to very pale straw-yellow colour, a melting point of 47–53°C, and an oil content of 10–25% in Bio Green Wax's customised specification.

LMO stands for Light Machine Oil — the specific lubricating oil distillate fraction from which this slack wax grade is derived. Light machine oil is a low-viscosity lubricating oil historically used in light industrial machinery, and the wax fraction crystallised from this distillate cut during refining is designated as Slack Wax LMO.

Slack Wax LMO is produced as a byproduct of the solvent dewaxing process in lubricating oil refining. The light machine oil distillate fraction is chilled in the presence of a solvent (typically methyl ethyl ketone or propane), causing the waxy components to crystallise. These crystals are then separated from the liquid oil by filtration, yielding the raw slack wax. The resulting product retains a proportion of residual oil — between 10–25% in Bio Green Wax's specification — which distinguishes it from more refined paraffin waxes.

The ASTM D-1500 colour of Slack Wax LMO is maximum L1.0 — a designation that places it among the lightest petroleum wax products commercially available. The 'L' prefix indicates the product is lighter than the standard 1.0 colour chip on the ASTM comparator scale, appearing as near water-white to very pale straw-yellow in practice. This light colour reflects LMO's low aromatic content and high paraffin purity relative to heavier slack wax grades.

The primary difference is oil content. Fully refined paraffin wax contains less than 0.5% residual oil and is virtually colourless and odourless, meeting food and cosmetic grade purity standards. Slack Wax LMO retains 10–25% residual oil, giving it a softer, more unctuous character and a slightly yellowish tint. LMO is not suitable for food or direct cosmetic contact without further processing, but it is significantly less expensive and serves a wide range of industrial applications where oil content is not a disqualifying factor.

The melting point of Slack Wax LMO is 47–53°C as measured by ASTM D-87. This is the lowest melting point among the four slack wax grades (LMO, SPO, MMO, DAO), reflecting its lighter molecular weight and lower carbon chain length distribution. The congealing point (ASTM D-938) sits at 46–53°C, closely aligned with the melting point as expected for a predominantly paraffinic wax.

Bio Green Wax Ltd supplies Slack Wax LMO with an oil content of 10–25% as measured by ASTM D-721. This is a customised operational range that reflects the actual product supplied rather than a theoretical maximum. Buyers requiring a tighter oil content window within this range should discuss specific batch requirements with the sales team, as oil content can affect downstream processing consistency.

The kinematic viscosity of Slack Wax LMO at 100°C is 3.1–4.2 centistokes (cSt), measured by ASTM D-445. This is the lowest viscosity of all four slack wax grades, making LMO the most fluid at elevated temperatures. This low viscosity is beneficial in processing environments where the wax needs to be pumped, blended, or applied as a coating — reducing energy requirements and equipment stress compared to heavier grades such as MMO or DAO.

The minimum flash point of Slack Wax LMO is 145°C as measured by the Pensky-Martens Closed Cup (PMCC) method per ASTM D-93. The flash point indicates the minimum temperature at which vapours from the heated wax can ignite in the presence of a flame. A flash point of 145°C means LMO is classified as a combustible material rather than a flammable liquid, but appropriate precautions should still be applied during melting, processing, and storage. Storage should be away from open flames and oxidising materials.

Slack Wax LMO has a maximum sulphur content of 0.30%wt as measured by ASTM D-1552. This is higher than the other three slack wax grades (SPO, MMO, DAO), which all carry a maximum of 0.20%wt. For most applications — candles, paper coatings, MDF waterproofing — this difference is inconsequential. However, for rubber and tyre applications where sulphur content can interfere with vulcanisation chemistry, buyers should evaluate whether the 0.30% maximum is within acceptable limits for their specific formulation.

Slack Wax LMO serves a wide range of industrial applications, including: candle manufacturing as a paraffin extender and base wax; match and firelighter impregnation; MDF and particleboard waterproofing; rubber compounding as a processing aid and anti-ozonant; paper and board moisture-barrier coatings; textile lubricant and softener formulations; wax emulsion manufacturing; fully refined paraffin wax feedstock for deoiling operations; and carbon paper and ink manufacturing.

Its low melting point and good fluidity make it the preferred slack wax grade for applications requiring easy melt processing.

Yes, Slack Wax LMO is used in candle manufacturing, primarily as a blending component or extender rather than a standalone candle wax. It is blended with fully refined or semi refined paraffin wax to adjust hardness, melt pool characteristics, and cost. Its pale colour (ASTM ≤ L1.0) means it does not significantly affect the visual appearance of light-coloured candles. It is not suitable as a standalone candle wax due to its oil content, which can affect burn performance and fragrance loading at higher concentrations.

Yes, Slack Wax LMO is used as a processing aid and anti-ozonant in rubber compounding. In rubber formulations, waxes migrate to the surface of the vulcanised article to form a thin protective film that shields the rubber from atmospheric ozone degradation — a process known as static ozone protection. LMO's light molecular weight and fluid character make it compatible with rubber mixing processes. However, buyers should verify sulphur content requirements with their technical team, as LMO carries a higher sulphur maximum (0.30%wt) than the other slack wax grades.

Yes, one of LMO's key industrial roles is as a deoiling feedstock for the production of fully refined paraffin wax. In deoiling plants, the residual oil in LMO is removed through further solvent dewaxing and filtration steps until the oil content drops below 0.5%, at which point the product meets fully refined paraffin specification. LMO's relatively low viscosity compared to heavier slack wax grades (SPO, MMO, DAO) reduces the energy required for chilling and filtration in the deoiling process, making it the preferred feedstock for this application.

No. Slack Wax LMO is not suitable for direct food contact, food coating, or pharmaceutical applications. Its oil content of 10–25% and residual aromatic compounds mean it does not meet the purity requirements of food-grade regulations (FDA 21 CFR, EU Regulation 10/2011) or pharmaceutical standards. For food, cosmetic, or pharmaceutical wax applications, fully refined paraffin wax (oil content <0.5%) should be specified instead.

Bio Green Wax Ltd operates as a B2B supplier of Slack Wax LMO in industrial bulk quantities. Minimum order quantities are discussed based on your specific requirements and destination. Please contact the sales team via biogreenwax.com or at info@biogreenwax.com to receive pricing and MOQ information tailored to your volume and logistics needs.

Bio Green Wax Ltd offers flexible international shipping terms for Slack Wax LMO, including FOB (Free on Board), CIF (Cost, Insurance and Freight), and DDP (Delivered Duty Paid). DDP is the most buyer-friendly option as it includes all freight, insurance, and import duty costs to the named destination. The most appropriate Incoterm depends on your location, logistics infrastructure, and preference for cost control. Contact us to discuss the best option for your shipment.

Bio Green Wax Ltd supplies full trade and compliance documentation with every shipment of Slack Wax LMO. Standard documents include a Certificate of Analysis (CoA) covering all ASTM-tested parameters (colour, melting point, oil content, viscosity, flash point, specific gravity, sulphur content), a Safety Data Sheet (SDS/MSDS), commercial invoice, packing list, and bill of lading. Additional documentation such as a Certificate of Origin or specific regulatory compliance documents can be arranged on request.

Slack Wax LMO should be stored in a cool, dry, well-ventilated location away from direct sunlight, heat sources, and open flames. As a combustible material with a flash point of minimum 145°C, it should be kept away from ignition sources during storage and handling. In solid form at ambient temperature, it is stable and non-reactive. Bulk storage in heated tanks is common in industrial settings, where temperatures should be maintained above the melting point (47–53°C) but well below the flash point. Containers should be kept sealed when not in use to prevent contamination.

Yes. Bio Green Wax Ltd is a UK-registered global B2B supplier and exports Slack Wax LMO to buyers across Europe, the Middle East, Asia, and Africa. We have experience handling international logistics for bulk wax shipments and can assist with documentation, compliance requirements, and preferred Incoterms. Visit biogreenwax.com or contact info@biogreenwax.com to discuss your country-specific requirements.