The Yellow Brick Road
Beginning with the introduction of “lightweight” aerosol cans, the fledgling U.S aerosol industry “followed
the yellow brick road” from 1947 to 1953, expanding at up to 50% in some years and always using
non-flammable propellants. By this time, shaving creams evolved into a major aerosol product, with
1953 sales reported to be 27.5 million units. The formulas typically included about 9% CFC-12 or 10%
CFC-12 (60%)/CFC-114 (40%).
In that year, Carter Products Inc. applied for what became known as the “Spitzer Patent” in the U.S.,
UK and perhaps elsewhere. The protected formulas contained 5% to 30% detergents, such as sodium,
potassium and amine soaps. When its patent was granted, the company had the option of allowing
selected other marketers to continue selling aerosol shave creams, provided they paid royalties.
One marketer antagonized Carter by asserting that the patent was invalid. A court was appointed for
litigation. After some lengthy deliberations, the judge decided in favor of Carter, upholding its patent.
Interestingly, the term “several” was defined as representing 3–7 and a “fatty acid” was defined as limited
to lauric, myristic, palmitic and stearic acids.
However, more importantly, Carter’s competitors rather quickly circumvented the patent by converting
from CFC propellants to about 4.0% of an iso-butane/propane mixture—typically known later as
A-46, a terminology developed by the Phillips Petroleum Co. around 1958.
This conversion was a major event. It placed hydrocarbon propellants firmly into play, despite their
flammability. Shave cream fillers had to take unprecedented measures to preserve life and property assets.
However, the cost of propellants for shave creams usually decreased by over 90%, which was partly
offset by these protective capital expenditures. Production equipment suppliers were quick to convert
motors, gassers and other equipment into well-grounded explosion-proof versions.
Initially, the hydrocarbon odor was a minor problem if these propellants came from clean gas wells where impurities
such as unsaturates and hydrogen sulphide (H2S) were very low. Better distillation was required for pressure
reproducibility.
In 1956, one source of “butane” sold products with pressures ranging from about 17 to 32 psi-g. (70°F) (a similar
“butane” range was then prevalent in the UK, as reported by Herzka). These quality difficulties were soon corrected.
December 2018 SPRAY 33