Grease Solids After PTFE: Graphite, MoS2, WS2, hBN and CaCO3

What PTFE was doing (friction, dryness, chemical inertness)

PTFE earned its drum space doing four jobs at once: lowering breakaway and running friction as a soft layered solid, adding dry-film insurance when oil starves, staying chemically inert across almost any environment, and doing it all in white — which is why it became the default solid in food-adjacent H1 greases and 'clean' automotive pastes. PFAS pressure removes the molecule, not the four jobs. Any replacement programme that starts by shopping for 'a PTFE substitute' has already misunderstood the assignment: you are replacing four functions, and no single powder on the market carries all four.

What the documents are evidence for

Three sources frame the problem. The WO 2024/017518 ionic-liquid grease filing (granted as US 12,612,575 B2) still lists PTFE among its optional solids — alongside MoS2, graphite, graphene, hBN, WS2, CaCO3 and silica — which is evidence that even a 2024–2026 patent treats solids selection as an open menu, not a settled answer. The Technologies 2026 hBN study is evidence that one fashionable white solid can make electrified bearings worse. Industry H1 briefings are evidence that food-grade reformulation is the commercial driver. We cite all three as prior art or literature, not as product endorsements.

Solids table: load, temp, colour, NSF, conductivity

The selection variables, in the order customers actually feel them: load and speed regime (layered-lattice solids like MoS2 and graphite want slow, heavy, sliding contacts; CaCO3 is a mild EP partner inside soap structures); temperature ceiling (graphite and MoS2 oxidise in air in the few-hundred-°C class; hBN and CaCO3 go higher); colour (MoS2 and graphite are black and stay visible; hBN, CaCO3 and silica are white); food-contact status (an NSF H1 ingredient list decides, not a colour); and electrical behaviour (graphite conducts, hBN is dielectric, MoS2 sits between). A solid that wins three columns and fails the fourth is a failed reformulation, so the columns belong in one table on the formulation file, scored per duty. Graphene sits in the menu too, but treat it as research-grade until a supplier can hold particle size and price across two orders.

What they are not evidence for

A patent's laundry list of optional solids is not a recommendation — claim drafting casts wide nets by design. A paper's single-matrix result is not a universal verdict on that solid. And neither is evidence that any candidate is 'PFAS-free certified' for your market: that status comes from supplier declarations and your own ingredient file, not from a journal's DOI.

Open gear vs CV joint vs H1 vs EV

Duty slices the menu fast. Open gears and slow, heavily loaded slides: MoS2, graphite and CaCO3-class solids have decades of evidence, colour be damned. CV joints: organic-molybdenum chemistry and calcite/borate packages do the EP work where a dry solid would be boot-hostile ballast. H1 food-adjacent: white, listed solids only — historically PTFE, now hBN, CaCO3 or silica candidates with an ingredient file that survives an audit; our food-grade formulation page covers the certification frame. EV and electrified bearings: the Technologies 2026 caution applies — a dielectric white solid made bearings worse under current, so this duty needs electrified testing before any solid is invited. The MoS2 guide and open gear pages hold the duty detail.

What a formulator changes on the bench

A PTFE-replacement screen runs like this:

• Functions first: write which of the four PTFE jobs the SKU actually used — most SKUs used two.
• Candidate arms: one white solid and one dark solid where colour allows, at two particle sizes, milled in (three-roll) rather than stirred, with fineness-of-grind recorded.
• Friction where it matters: SRV or four-ball (D2266/D2596) at duty temperature, plus breakaway friction at start-up — PTFE's breakaway benefit is the one most replacements quietly lose.
• Stability: bleed, worked penetration and a 90-day drum stand, because platelet solids settle and agglomerate in ways PTFE's fluffy grades never did.

A replacement matrix, not a single powder

The deliverable is a matrix: duty down the side, the four functions across the top, candidate solids scored in the cells, and the test method named in every scored cell. Most reformulations end with two SKUs where PTFE allowed one — a white H1-grade solid package and a dark industrial package — and that duplication is a cost of compliance, not a formulation failure. Keep the matrix dated; supplier PFAS positions and NSF listings change, and last year's answer can quietly expire.

The design-around question

The design-around question: for each duty, which solid (or solid-plus-organic-molybdenum pair) reproduces PTFE's start-up friction curve without its persistence profile — and which of the four functions can you honestly hand back to the base oil and thickener instead of a powder? The cheapest PFAS-free solid is often the one the formulation never needed. That is a formulation answer, not a purchasing answer.

What Lubechem will and will not claim

Lubechem Consultant is an independent formulation house in New Delhi, led by Er. Manoj Kumar and practising since 2010. The patent solids list, the hBN study and the H1 briefings are cited as prior art and literature — evidence for a selection problem, not a shopping list. We do not sell solids, we do not certify PFAS status, and we do not call any powder a drop-in PTFE replacement.

What we will do is build the four-function matrix for your duties, run the friction and stability screen, and document the ingredient file your audit actually asks for. If a PTFE-removal deadline is driving this, send the affected SKUs and their duties; the matrix comes before any purchase order.

How to use this filing as prior art — not as a recipe

Literature and prior art

Citations below are orientation, not a freedom-to-operate opinion. Lubechem does not copy claimed compositions and does not treat a patent as a product endorsement.

1. WO 2024/017518 A1 solids list; Technologies 2026 hBN caution; TUNAP CaSX H1 briefing — cited as prior art or literature, not as a product Lubechem sells
2. ASTM D217 cone penetration / NLGI grade — consistency, not chemistry
3. ASTM D2265 dropping point — lab fluidity, not continuous service limit
4. ASTM D1264 water washout — wet service screen, not a seawater proof
5. DIN 51821 FE9 / ASTM D3336 — bearing life nearer to operating reality than drop point

Related formulation pages

• Guides/mos2 Grease
• Open Gear Grease Formulation India
• Food Grade Lubricants Formulation