Making plastics from crops isn’t anything new. Henry Ford—who once had a suit made from soy material—used soybeans in his vehicles from the very beginning. Between molded plastic parts and paint, the Model T at one point incorporated 60 pounds of soybeans per vehicle, and in 1941, Ford debuted a car made of soy plastic. (Sadly, when World War II suspended auto production, the soy plastic car fell by the wayside.)

But Ford has continued to incorporate sustainable innovations with soy. In 2003, the company’s Model U concept also featured soy-based seat cushions and a soy-based resin composite tailgate.

Since 2008, Ford Motor Company has used soy-based polyurethane flexible foam in vehicle seats. That they started with a sports car—the Mustang—was no accident. They knew using the product in the Mustang would make a statement, that its success would set the stage for more biobased adoption.

And it worked. Since 2011, every North American-built Ford product uses soy-based foam in its seat backs, seat cushions and headrests. Just six years later, the company estimated that 18.5 million Ford vehicles used the soy-based foam, converting 578 billion soybeans into an alternative to petroleum-based foam.

Today, soy-based plastics developments haven’t slowed; on the contrary, they’re ramping back up again, with no signs of waning.

At Airable Research Lab, recent developments include a degradable soy-based ester polyol, a soy epoxy hardener and soybean hull-reinforced polymers. Applications range from automotive and aircraft coatings to adhesives and water bottles.

In addition to Ford, many companies are using soy-based plastics commercially for products such as mattresses, garden pots, ink, carpet backing and more.

Replacing or partially replacing petroleum-based ingredients such as polyols and polyurethane helps reduce the product’s carbon footprint, and it contributes to reducing emissions, reducing renewable energy use and helping reduce costs by decreasing the requirement for other ingredients. Companies are realizing the benefits of soy-based plastics.

Activities stemming from Airable Research Lab, the USDA’s Biopreferred® Program, USB-funded research and the Illinois Soybean Association’s Soy Innovation Center are spurring development and breaking down the barriers to commercial availability of soybased or infused products.

And it’s working. The Biodegradable Products Institute (BPI), which tests and certifies biodegradable and compostable goods, reports 10,000 BPI-certified products are now on the market including compostable bags, foodservice items, resins and certified packaging materials. That number more than doubled in just a three-year period.

So what’s next? Let’s take a look.

Plastics 101

Before we jump into some of the newest soy-based plastic options, we need to understand plastics themselves. Plastics are polymers—substances made of many repeating units. For plastics such as polyethylene (PE, LDPE, HDPE), polypropylene (PP) and polystyrene (PS), those units are hydrocarbons, which most often come from petroleum. When we fractionate hydrocarbons and combine them with other ingredients, we can make plastics.

The word plastic derives from the Greek word meaning “capable of being shaped or molded.” And that is what makes plastics so useful: they can be pressed, molded or extruded into many different shapes and forms.

Some of the most common are polyethylene terephthalate (PET) used for water bottles, polystyrene used for insulated food containers and polyvinyl chloride (PVC) used for flexible applications such as garden hoses. Often, industrial plastics are referred to as resins, commodity or specialty.

Many plastics are low-cost and single-use, but when we talk about plastics, we’re using it as an umbrella term that also includes foams, coatings, adhesives, binders and other industrial components. Because petroleum-based plastic products usually aren’t biodegradable, they end up in landfills. That’s where soy-based plastics come in, as a sustainable, biodegradable solution.

Why Does Soy Make Good Plastic?

Soy is abundant; it is accessible; it is a renewable resource.

Because soy is more flexible, it is good for thermoplastic elastomers, which can be used in elastic coatings that withstand a lot of impact.

As a renewable resource, soy is economical and biodegradable, and its potential for many different applications makes it appealing for the plastics industry.

Interest in bioplastics, which includes soy-based plastics, has skyrocketed in the recent past, and in turn, much development and commercialization has followed. The past decade has seen intensive research in the segment, with solutions that allow industrial producers to reduce dependence on petroleum without sacrificing performance. We could spend the entire issue covering bioplastics, but for now, let’s hone in on some of the most significant in the market today.

Cargill Priplast™, Pripol™, Priacid™ and Priamine™

Cargill offers a line of what it calls “smarter” products for coatings and adhesives that can be used in a wide range of applications. These building blocks make it possible for manufacturers to reduce their carbon footprint and improve their products’ in-use sustainability.

Cargill offers a wide-ranging line of industrial ingredients. Its soybean-based polyols can replace petroleum-based polyols, with applications including bedding, furniture and automotive seats. With its polyester polyol products, manufacturers can replace and modify any polyurethane application, such as automotive, electronics and sporting goods.

Cargill’s polyamides and polyimides make a flexible water barrier, much like nylon, used as a hardener for epoxy adhesives and protective coatings. By using the company’s specialty dimer fatty acids, azelaic acid and dimer diols to modify polymers, industrial designers can reduce polymer density in lightweight applications such as food packaging.

This biobased product line’s advantages are in its ability to deliver strength, stability and flexibility while allowing formulators to adjust to their specific application and product needs.

Emery Oleochemicals

Ohio-based manufacturer Emery Oleochemicals uses natural oils and fats to produce azelaic acids, pelargonic acids, stearic acids, oleic acids, tallow fatty acids, vegetable fatty acids, refined and technical grade glycerin and general-purpose esters caters.

Their dimer acids are an exciting development. Textile manufacturers can use them in polyesters and other fabrics.

They also have great potential to replace PETs in water bottles, packaging and other plastics.

PHAs or Polyhydroxyalkanoates

Water-bottle innovation using renewable ingredients doesn’t stop there. For example, we’re seeing a great deal of development in PHAs, or polyhydroxyalkanoates. They have many of the same properties as two of the most widely used plastics, polypropylene and polyethylene. Not only can PHAs be used for injection molding, they also have a low water permeation rating for better shelf stability and are fully biodegradable.

PHAs offer stability and versatility that appeals to industrial engineers and manufacturers. These biobased polymers are being widely used as a direct replacement for PETs, and they can also be used in any food packaging as an alternative to synthetic plastics.

In fact, food packaging and biomedical applications are two of the main areas toward which research is being directed. PHAs are ideal for food packaging. They can prevent spoilage and have characteristics including nontoxicity, thermoplasticity (moldable when heated, solid when cooled), hydrophobicity (ability to repel water) and superior barrier properties.

Other applications for PHAs include as a replacement for metal parts, in 3D printing, in cosmetic packaging, as cleaning material and as a flame retardant. The potential for PHAs continues to evolve.

The Future

In the future, soy proteins are a category to watch, as they can be denatured to make bioplastic. Soy protein is inhomogeneous and hard to control, but research is promising. We are seeing more interest in research into proteins and meal and how to make them into bioplastic, with a goal of better degradability and better sustainability.

Dylan Karis is Lead Chemist for Airable Research Lab, which provides early-stage soy-based materials research, reducing the financial risk for industrial and consumer partners.

For more information visit www.airableresearchlab.com.