#774 1941 · The Sherwin-Williams Company · Paint and coatings chemistry
Wartime rationing choked off the oil every paint needed, so Sherwin-Williams built a paint that barely needed any
the problem
Wartime rationing choked off the linseed oil every paint needed
background
Since Michelangelo's era, the most durable interior wall paints had been oil-based, using linseed oil as the binder dissolved into an organic solvent like turpentine or mineral spirits — a formula that gave good coverage and washability but depended entirely on that oil supply. As the United States geared up for World War II, linseed oil was rationed for military use, and Sherwin-Williams's plant engineers and chemists scrambled the way every paint manufacturer did: hunting the country for alternative raw materials, experimenting with old, half-forgotten oils and resins to keep production running on the same oil-and-solvent formula.
That search for substitute oils only went so far, because it was still competing for the same broad category of scarce material the war effort also needed. Water-based paint had been tried before in cruder forms — whitewash going back to antiquity used milk casein to bind lime — but those earlier water-based formulas had poor washability and durability, which was exactly why the entire architectural paint industry had settled on oil-and-solvent formulas as the only reliable way to get a paint that held up to scrubbing.
what everyone would do
Every paint manufacturer facing wartime linseed oil rationing did the same obvious thing: hunt for substitute sources of oil and solvent to keep making paint the traditional way. Sherwin-Williams's own chemists and purchasing agents did exactly that at first, combing the country for old, half-forgotten oils and resins and converting old equipment to process them, staying within the same oil-and-solvent formula the entire industry had used for centuries.
what they saw
Sherwin-Williams's chemists saw that searching for substitute oils was still competing for the same category of scarce material the war effort needed — the actual fix was to need far less of it in the first place. If casein and a much smaller amount of oil could be emulsified into water rather than dissolved into solvent, the paint's overwhelming bulk would be an abundant, unrationed material, and the scarce binder would only need to supply durability and washability, not carry the whole formula.
the move
Sherwin-Williams chemists emulsified casein, a milk protein, together with a much smaller quantity of linseed oil (and later tall oil, a wood byproduct) suspended in water rather than dissolved in solvent, using water as the paint's primary liquid component instead of oil or organic solvent. The result, launched as Kem-Tone in September 1941, was the first water-based interior paint durable and washable enough to compete directly with oil paint.
why it works
Because water replaced organic solvent as the paint's primary liquid volume, Kem-Tone's formula needed only a small fraction of the linseed oil a traditional oil-based paint required for the same coverage, sidestepping the rationing bottleneck entirely rather than fighting other manufacturers for what little oil remained. The emulsification chemistry still delivered enough binding power for the paint to withstand rubbing and washing, the one thing earlier water-based formulas like whitewash had never managed, which is what let Kem-Tone actually compete with oil paint on performance rather than being a wartime downgrade.
the payoff
Because water, not oil or solvent, now made up the bulk of the paint's liquid volume, Kem-Tone needed only a fraction of the scarce linseed oil a traditional formula required, sidestepping the rationing bottleneck entirely rather than competing for what little oil remained available. More than 10 million gallons sold within three years, and Sherwin-Williams paired the launch with a second shortage-driven invention, engineer Richard Adams's paint roller, patented as an alternative to paintbrushes after the China-Japan war cut off the hog-bristle supply, bundling both wartime substitutions into one "do-it-yourself" product line.
where it breaks
This only works when the scarce input can genuinely be reduced to a smaller supporting role rather than eliminated — Kem-Tone still needed linseed oil, just far less of it, and the underlying emulsification chemistry had to be solved well enough that the final product performed as well as what it was replacing, or customers would simply have gone without rather than accept an inferior wartime substitute. It also depends on the substitute carrier actually being abundant and compatible with the product's other requirements; a formula that swaps one scarce input for a different scarce one hasn't solved the underlying problem at all.
what came after
Kem-Tone proved that a water-emulsified paint could be genuinely durable and washable, opening the door to the waterborne paint technology that today makes up roughly 80 percent of all architectural coatings sold, and the roller it launched alongside remains the standard household paint applicator. The American Chemical Society designated Kem-Tone a National Historic Chemical Landmark in 1996.
references
- [1]Kem-Tone Wall Finish (National Historic Chemical Landmark)American Chemical Society, 1996acs.org
- [2]Sherwin-WilliamsCleveland Historical, 2019clevelandhistorical.org