This blog post explores the potential and limitations of engineering plastics, the next-generation material poised to replace metals.
The advent of plastics has profoundly transformed and enriched human life over the past century. Simultaneously, materials long used in human life—such as stone, wood, and textiles—gradually ceded their place to plastics. The 20th century saw the emergence of simple everyday plastic products like nylon stockings, Styrofoam, and plastic bags, heralding the dawn of the plastic age. Entering the 21st century, advanced plastics that surpass the limitations of existing materials have emerged, rapidly encroaching on the domains of traditional materials like metal, glass, and wood. In particular, ‘Engineering Plastics’ are leading a new industrial paradigm by focusing on replacing metal parts based on their lightweight yet strong properties.
The concept of engineering plastics gained traction in the 1960s when the American chemical company DuPont developed polyamide resin under the slogan “a material that challenges steel.” While properties vary by type, these plastics generally offer advantages such as being stronger than steel, easier to process than aluminum, and more chemically stable than gold or silver. Notable examples include Kevlar, which replaced bulletproof helmets and vests with a harder material, and polyaramid, which displaced steel plates used in aircraft fuselages due to its stronger yet lighter properties. Engineering plastics are rapidly replacing areas previously dominated by traditional materials, and continuous technological development continues to pursue complete metal substitution.
Engineering plastics offer numerous advantages over metals. They offer high strength, light weight, excellent durability and elasticity, as well as chemical stability that makes them easy to process and resistant to corrosion. Furthermore, while metals must be processed as-is, plastics possess the significant advantage of allowing various processing techniques to be applied to impart desired properties. This flexibility enables plastics to adapt to diverse industrial fields and opens possibilities for new evolution.
Recently, as ‘green technology’ has become a hot topic across industries, environmentally harmful technologies are gradually being phased out. Particularly in the automotive industry, identified as a major contributor to urban smog, new technology development targeting eco-friendliness is actively underway. The American Chemical Society has published experimental results showing that reducing a car’s weight by 10% improves average fuel efficiency by 5-7%. In this context, engineering plastics hold clear advantages over metals. ‘Carbon fiber composites,’ which combine engineering plastics with carbon fiber, possess ten times the strength of metal while being four times lighter. This material is gaining attention as a core solution for automakers responding to fuel efficiency regulations set by governments worldwide and is widely used in actual vehicle weight reduction.
Engineering plastics extend beyond being merely eco-friendly technologies. They are also actively utilized in technologies designed to enhance consumer convenience and satisfaction. The functionality of portable electronic devices has largely reached a saturation point, with ‘flexibility’ now emerging as the most prominent focus. Devices that can be folded and rolled enhance portability and open the possibility of replacing multiple media with a single device. However, traditional metal materials are difficult to bend and break easily, making it hard to meet these technical demands. Consequently, electronics manufacturers are gradually replacing internal components from metal to plastic. Display materials like LCDs have already been replaced by plastic-based substances, and ongoing technological development means internal components are also losing their place.
Of course, challenges remain before engineering plastics can fully replace existing materials. One of the biggest hurdles is ‘price competitiveness’. Producing plastics with superior properties requires complex and costly manufacturing processes. For example, carbon fiber composites, which are expected to replace steel in car bodies, currently cost around $30 per kilogram, limiting their widespread adoption. In fact, the average annual growth rate for this material’s usage is only 2.8%. For complete replacement, reducing the unit price to below $10 per kilogram is essential. Furthermore, engineering plastics are less heat-resistant than glass or metal and have lower electrical conductivity. Electrical conductivity refers to how well a material allows current to flow, a crucial property for electronic devices like smartphones and MP3 players.
Nevertheless, engineering plastics will not remain confined by these limitations. As mentioned earlier, plastics are materials with the potential to acquire desired properties through new manufacturing processes. Indeed, the research of recent Nobel Chemistry Prize winners is based on innovative technologies that overcome plastic’s weaknesses, offering us great hope. In modern society, where resources are increasingly depleted and environmental issues are becoming critically important, engineering plastics are a powerful solution capable of compensating for the shortcomings of existing materials and presenting sustainable alternatives. And their potential remains limitless.
Growing alongside the changing times, engineering plastics will undoubtedly emerge as the leading new material in the near future, challenging the dominance of steel. We are about to enter an era of this new material, enabling what existing materials could not and transcending limitations.
