In the 1940s Soybean Plastics Were Futuristic; They Still Are

The Syracuse University Plastics Collection has two automobile license plates made out of soybean-based fiberboard, an early instance of the use of renewable materials to make a "natural" plastic.  This process to find "new" plastic materials continues to today with widespread research and product development of plastics derived from corn, switchgrass and mushroom.  These plates come from Illinois, the state along with Michigan that most successfully used soy-based materials, in large part due to the efforts of Henry Ford who for many years previous had championed soybeans as a renewable material that could be used to create a wide range of plastics, especially for use within the automotive industry. Illinois used soybean-based plates from 1943 to 1948.

License Plate

The earliest American license plates were made out of porcelain baked onto iron or ceramic with no backing, which made them fragile and impractical. Few of these earliest plates survive. Later materials included cardboard, leather, and plastic, and during the early 1940s when there were wartime shortages of many materials, some states issued fiberboard plates made from soybeans. This use of natural materials harked back to the earliest era of cellulose-based plastics, and looked forward to today's efforts at making "green" plastics from natural bio-degradable materials.

On August 31, 1941 Henry Ford unveiled a plastic-bodied car as part of his effort to create an economy that joined industry and agriculture. The car was constructed of panels that Lowell E. Overly (who was instrumental in creating the car) claimed were made of "...soybean fiber in a phenolic resin with formaldehyde used in the impregnation." The plastic was developed at Ford's Soybean Laboratory in Greenfield Village.

License Plate

It was also in the 1940s that the extensive experiments of bonding wood pulp and other natural fibrous material (including soy fibers) with polymers took place (at the New York State University College of Forestry and elsewhere), but it is doubtful that synthetics were needed to make the board for these license plates. Since license plates were not designed to receive excessive stress or pressure, nor to last long, heat and pressure with perhaps a natural bonding agent such as soy flour may have been sufficient to create the boards from which these plates were cut. Still, license plates faced unexpected challenges. In 1943 a goat is reputed to have eaten an Illinois license plate made of soybean-derived fiberboard, like the one featured here.

Perhaps because of the interruption in the Ford-sponsored research during the war years, soybean plastics failed to catch on and by the end of the 1940s the promise of soybean plastics was being dismissed. In the 1950 edition of the Modern Plastics Encyclopedia and Engineer's Handbook, a wrap up of development in plastics entitled "A Decade of Plastics" summed up soybean plastics this way: "The leader in this crowd [of disappointing plastics] is the much heralded soybean plastic that never materialized in any worth-while quantity. Probably more hubbub was created over its possibilities than any plastic ever mentioned. Even today, a great portion of the public ties plastics to soybeans but a potential purchaser couldn't buy a pound of soybean plastic molding powder or laminating resin. First, it is uneconomical to produce; secondly, its properties are not equal to or at least no better than other plastics now on the market." (p. 40).

These license plates also illustrate an early phase in the development of fiberboard (which was first made in the 1920s), a material that has since been developed as major material for packaging, construction, furniture, displays, paneling, and other uses. Today, medium density fiberboard (MDF) is a widely used material primarily composed of lignocellulosic fibers combined with a synthetic resin or other suitable bonding system and bonded together under heat and pressure. Fiberboard is often seen as an environmentally friendly material because it recycles waste materials, but the use of formaldehyde resins can cause air-quality problems, especially in homes, that can lead to health problems. Therefore, researchers today are again focusing on soy-based plastics, especially the use of soy proteins as "truly green" bonding agents for lignocellulosic fibers. Soybean straw, on the other hand, remains a weak alternative for use in fiberboard, with relatively low water-resistance compared to the commonly used softwood fibers. It may be good for license plates, but is not yet ready for building materials.

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