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Hydrogenated castor oil (HCO), commonly called castor wax, is castor oil whose double bonds have been saturated with hydrogen. That single change turns a viscous liquid into a hard, brittle, odourless white wax melting around 85–88°C, while keeping the hydroxyl groups that make castor chemistry useful. HCO is supplied as flakes or powder and is used in greases and lubricants, cosmetics, coatings, polishes and hot-melt adhesives — and as the feedstock for 12-hydroxystearic acid and the PEG (ethoxylated) HCO grades.
Hydrogenated castor oil is the most widely used castor derivative. Chemically it is the triglyceride of 12-hydroxystearic acid — in plain terms, castor oil with its unsaturation removed. Because the hydroxyl groups survive hydrogenation, HCO keeps the polarity and reactivity that distinguish castor products, but now in a solid, wax-like form. That combination of hardness plus hydroxyl functionality is unusual among natural waxes and explains its broad use.
It is sold under several names — castor wax, HCO, hydrogenated castor oil — all referring to the same material. For where it sits among other castor products, see what are castor oil derivatives.
Production is a controlled hydrogenation:
The iodine value falls sharply during hydrogenation — from around 82–90 in the base oil to low single digits — and that drop is the standard measure of how complete the reaction is.
| Parameter | Typical value |
|---|---|
| Appearance | White to off-white flakes or powder |
| Odour | Odourless to faint |
| Melting point | ~85–88°C |
| Iodine value | Max ~3–5 g I₂/100g |
| Hydroxyl value | ~150–165 mg KOH/g |
| Acid value | Max ~2–4 mg KOH/g |
| Saponification value | ~176–182 mg KOH/g |
| Moisture | Max ~0.5% |
The low iodine value and high melting point are the two figures that define the product. For how to read these on a certificate, see understanding a castor oil CoA.
Which form suits you depends on how the material enters your process: melting into a batch favours flakes, while dry blending or matting effects in coatings usually call for powder.
HCO is a thickener and structuring agent in greases, and the starting point for 12-hydroxystearic acid used to make lithium greases — the most widely used grease class in industry.
Used to structure and harden lipsticks, balms, sticks and creams, giving body and stability without a greasy feel. It also helps suspend pigments evenly.
Acts as an anti-settling and matting agent, a rheology modifier and a gloss controller in paints and inks, and gives hardness to waxes and polishes.
Contributes to hot-melt adhesive formulations and serves as a lubricant and release aid in plastics processing.
HCO is the raw material for 12-hydroxystearic acid and for ethoxylated grades such as PEG-40 and PEG-60 hydrogenated castor oil — see PEG-40 vs PEG-60 HCO.
| Property | Castor oil | Hydrogenated castor oil |
|---|---|---|
| Physical state | Viscous liquid | Hard, brittle wax |
| Melting point | Liquid at room temp. | ~85–88°C |
| Iodine value | ~82–90 | Max ~3–5 |
| Hydroxyl value | ~160–168 | ~150–165 |
| Oxidative stability | Moderate | High |
| Typical role | Oil, feedstock | Wax, thickener, structurant |
HCO is a stable, low-hazard solid. Keep it in sealed bags or drums in a cool, dry place away from direct heat, and avoid prolonged exposure to high temperatures that would soften or cake the flakes. Shelf life is typically long in original sealed packaging. Always work to the safety data sheet supplied with your consignment.
Castor oil that has been hydrogenated to saturate its double bonds, producing a hard white wax (also called castor wax) melting around 85–88°C. It retains the hydroxyl groups of the original oil.
Yes. Castor wax is the common trade name for hydrogenated castor oil; both refer to the same product.
Greases and lubricants, cosmetics such as lipsticks and balms, coatings and inks as an anti-settling or matting agent, polishes, hot-melt adhesives, and as feedstock for 12-hydroxystearic acid and PEG HCO grades.
Typically around 85–88°C, though the binding figure for any batch is the one on its Certificate of Analysis.
