Evolution of the Aerosol Can Montfort A. Johnsen, Ph.D. Technical Ed itor T he first aerosol can was born in 1927 in the basement workshop of Eric Rotheim of Oslo, Norway. The nominal 12-ounce size weighed up to 14 ounces, or 397 grams (empty). The two brazed together steel parts were 0.09" (2.3mm) thick and could safely hold pressures of up to 1900 psi-g (131 bars). After patenting his invention, Rotheim used the cans to market ski waxes, insecticides and other products, all pressurized with dimethyl ether at first. Later, he used iso-butane, vinyl chloride and methyl chloride. The costly cans were supposed to be returned for refilling, but many were not. By about 1932, Rotheim’s little business collapsed. He was dispirited and died a few years later. He would not be duly recognized for his signal accomplishments for almost forty years. However, some scientists knew about the Rotheim patents (1,800,156 and 1,892,750). By 1932, when DuPont developed Freon 12 (dichlorodifluoromethane) as a non-flammable coolant for air conditioners, Midgley, Henne and McNary of DuPont utilized it in conjunction with Rotheim’s cans for refrigeration system refills and a few other applications. Midgley and Henne (inveterate cigar smokers) became vigorous supporters of the Consumer Specialty Products Association (CSPA—called CSMA at the time) Aerosol Division when it was formed in 1951 after a long and heated controversy; due to the high cost of the cans, the consumer market was almost non-existent. Then came World War II and things changed abruptly. In 1941, on islands such as Guadalcanal and the Marianas Archipelago, U.S. Marines fought two enemies: the Japanese and mosquitoes. Back in the U.S., the Generals contacted the U.S. Dept. of Agriculture (USDA), hoping they could help with the biting insect problem. The cumbersome piston-type pump spray insecticides were briefly considered, but then Dr. Lyle D. Goodhue (entomologist) recalled Rotheim’s work. He got some heavy-duty cans from Westinghouse. Adding about 10% to 15% of a pyrethrum concentrate and 85% to 90% Freon 12 propellant, he achieved a lovely spray of very fine particles that hung in the air much more effectively than the much coarser sprays from pump-action dispensers. In fact, when he demonstrated the new products to the generals (with nearly everyone taking a turn at spraying them), the very fine particles spread into many of the cages holding test insects, reportedly killing up to half of the entire inventory. The Armed Services almost immediately ordered about 60,000 of these insecticides which, from the size and shape, became unofficially known as “bombs.” The word “aerosol” was first uttered in a speech by Goodhue’s research partner, William N. Sullivan (engineer) in a 1943 speech given to fellow scientists in Washington, D.C. To the displeasure of some physicists and physical chemists, it quickly caught on and has been with us ever since. The development was made the subject of U.S. Patent No. 2,321,023. Under that original aegis, the USDA established regulatory control of all pesticides— insecticides, microbicides and rodenticides. As an intriguing side-issue, it did not take U.S. Marines long to determine that the cold aerosol sprays could be used to chill cans of beer, although quite a bit was needed. Huge numbers of aerosol cans were sacrificed to produce this welcome commodity. Quartermasters were asked to order more and more aerosols. It had the effect of convincing “top brass” that insecticide aerosols were a great asset to our fighting forces, and production increased into the millions. The military aerosol insecticides were released to the public in 1945. While sales were modest at first, canmakers became convinced that these products could be a WWI Marine raiders gathered before a Japanese dugout in Bougainville (Papua, New Guinea) A 1942 "Aerosect" insecticide "bomb" (12 oz.), flanked by CCC threepiece, double concave 1951 12-oz. aerosol cans, with valves soldered into the top segment. All three were bottom filled and chilled (-40°F) product mixtures. 20 Spray June 2016
Spray June 2016
To see the actual publication please follow the link above