Grease Additives

ZDDP treat rates in engine oil are typically 0.8–1.5% (delivering 800–1,500 ppm zinc), set by API and ACEA limits. In grease the chemistry works differently: ZDDP must partition into the base-oil phase of the grease matrix rather than dissolving in a uniform oil film, so the effective concentration at the contact surface depends on the oil-bleed rate of the grease, not just the total treat level. More critically, ZDDP — particularly secondary-alkyl grades — can interact with lithium soap thickener crystals and soften the grease, raise oil bleed or reduce drop point. Grease formulators typically use 0.5–1.5% ZDDP and validate the finished grease structure against un-additized controls. The correct approach is bench formulation trials in your grease cook, not direct transfer from oil data sheets.

The number is the NLGI consistency grade, not the additive level. NLGI grades run from 000 (near-fluid) to 6 (block-hard), set by worked penetration (ASTM D217): NLGI 0 is soft (355–385 dmm, for centralised systems and cold climates), NLGI 1 is medium-soft, and NLGI 2 is the most common general-purpose consistency (265–295 dmm). “EP” means the grease carries an extreme-pressure additive for load carrying, qualified by the Four-Ball EP weld point (ASTM D2596) — independent of the NLGI grade. So “EP 2” is an NLGI 2 grease with EP additive; “EP 0” is the same EP chemistry in a softer NLGI 0 grease. CheMost supplies the EP additive; the consistency grade is set by your thickener content.

“Moly grease” contains a molybdenum compound for boundary friction and EP performance under shock and slow-speed load (CV joints, fifth wheels, mining and construction pins). Two distinct chemistries are used: solid molybdenum disulfide (MoS₂) — the grey powder dispersed at 1–5% — and soluble organomolybdenum (MoDTC / MoDTP) friction modifiers. CheMost supplies soluble organomolybdenum friction modifiers, which are dosed into the oil phase and can be used in grease; see the friction-modifier range in the components catalog. Solid MoS₂, graphite, h-BN and PTFE are a separate class of dispersed solid lubricants — we can advise on their use and compatibility with your thickener, but they are formulated in as powders rather than supplied as one of our liquid concentrates.

Four tests are standard for EP qualification in grease: (1) ASTM D2596 / IP 239 Four-Ball EP — weld point and load-wear index in the finished grease; (2) FZG gear rig (DIN 51354) — load-stage performance in real gear geometry; (3) drop-point retention (ASTM D2265 / D566) — compare additized grease to an un-additized reference to confirm the additive has not degraded the thickener; (4) worked penetration (ASTM D217) after additive addition — a significant consistency change indicates thickener interaction. With calcium sulfonate complex greases the Four-Ball may show inherent EP from the thickener, so additive response is measured relative to the base CSC grease rather than mineral oil.

Mixing greases of different thickener types in service is risky: incompatible thickeners can collapse the structure of the mixture, softening it below the consistency of either parent grease and causing it to run out of the bearing. Lithium/lithium-complex and calcium sulfonate complex are not reliably compatible — a transition should be treated as a full purge-and-repack, not a top-up, unless a compatibility test (ASTM D6185, comparing the mixture’s penetration and drop point to the parents) confirms otherwise. The same caution applies to additives: every component must be validated in the specific grease. CheMost provides the compatibility flags we know from formulation data, but the finished grease cook is always the definitive test.

Calcium sulfonate complex (CSC) grease has inherent EP and corrosion protection from the calcium overbasing mechanism. In many applications no additional sulfurized EP is required, and the CSC grease without added sulfur will pass FZG load stages that would need explicit EP treatment in a lithium-complex system. For very high-load duty (continuous-miner sumps, kiln pinion drives, rolling-mill bearings) additional sulfurized EP or MoS₂ solid lubricant extends load capacity beyond the thickener’s contribution. The CSC structure generally tolerates modest added sulfurized EP at <3% without degradation, but confirmation bench tests at the target treat rate are recommended before scale-up.

Every commercial order is supported by: a TDS with chemical identification, active content, viscosity, flash point and typical treat-rate guidance; a GHS SDS for handling, storage and transport classification; and a per-batch COA confirming specification parameters. For EP additives the TDS includes available ASTM D130 (copper corrosion), active-sulfur and D2596 Four-Ball data where relevant. A Certificate of Origin is available for export shipments, and bench data for specific properties (EMCOR rust, oxidation induction) can be requested during qualification.

Standard stocked components (EP additives, antioxidants, ZDDP, rust inhibitors, tackifiers) ship within 7–14 business days of order confirmation. Minimum order for most liquid components is 200 kg (one drum); high-molecular-weight PIB grades and some specialty items may have IBC (1,000 kg) minimums due to heated-storage requirements for high-viscosity material. Trial samples of 1–5 kg for laboratory grease evaluation are available for qualified buyers at no charge. Send the product, required quantity and destination port for specific lead-time and pricing confirmation.