Thermoplastic composites are increasingly evaluated for use in smart device cases, like this Carbon I MK II smartphone launched by Carbon Mobile GmbH, to produce lighter, stronger, more recyclable electronic devices. Illustration by Susan Kraus, CW
Fiberglass composites are reported to be the most common insulating material in printed circuit boards (PCB), the structures that connect electronic components to each other in most consumer electronic devices.
Increasingly, composites also show much potential for use in other electronic applications, such as covers for devices like smartphones, laptops or smartwatches. Over the past several years, R&D projects and prototypes have demonstrated composites as viable alternatives to metals to produce lighter, more durable, radio-transparent device components; more recently, sustainability and recyclability of thermoplastic composites in particular have made these materials even more attractive for consumers.
New developments are often led by innovations in materials geared specifically toward the electronics market, especially carbon fiber-reinforced thermoplastic polymer (CFRTP) composites.
For example, Covestro’s (Leverkusen, Germany; Shanghai, China) Maezio brand of continuous CFRTP composites, which come in tape or sheet form, have been used in smartphone cases as well as a variety of other consumer applications. In 2022, Covestro announced that it has partnered with Dutch smartphone company Fairphone (Amsterdam, Netherlands), and that some of Covestro’s new product line of post-consumer recycled polycarbonate and thermoplastic polyurethanes (TPU) were used in Fairphone case components.
The Fairphone 4, with a glass fiber-reinforced center frame, made in part with recycled materials from Covestro. Photo Credit: Fairphone
In addition, the Carbon I MK II (Mark Two) smartphone from Carbon Mobile GmbH (Berlin, Germany) was launched in 2021 and was designed with a CFTRP cover from Lanxess (Cologne, Germany), built via a patented Carbon Mobile process. Benefits of the case are said to include very light weight, strength and radiolucency, as well as a fully thermoplastic shell for facilitating disassembly and recycling at the product’s end of life (EOL).
Research work continues in this field to optimize materials for the needs of smart devices and to solve challenges that may arise. For example, Arris (Berkeley, Calif., U.S.), known for its additive molding process, has said it is targeting consumer electronic components like smartphones. In June 2022, Arris published details about a study the company conducted to characterize the radio frequency (RF) response of glass fiber and carbon fiber composites made via its process for use in smartphone covers. The results demonstrated a lighter, stiffer cover that maintained RF levels needed for enabling the electronic components inside the phone to communicate effectively with antennas and cell towers.
Another project reported in 2022 by CW is a study involving researchers from several Japanese universities, who used cellulose nanofiber as a filler with a composite component to help solve challenges with effective heat dissipation within electronic components. The nanofiber films that were created are also said to be recyclable at the product’s EOL.
Beyond smart devices
Smartphones and laptops may be the reported use of composites in consumer electronics, but other applications can benefit from composites’ light weight, durability and radio-transparent properties. For example, in 2022, CW reported applications such as:
- A digital watch with a carbon fiber composite case made stronger and more durable via a 3D printing process from 9T Labs (Zurich, Switzerland);
- A robotic carbon fiber composite exoskeleton for helping workers lift heavy items in factories, manufactured by automotive supplier Mubea (Atterndorn, Germany) for German Bionic (Augsburg, Germany);
- And filament-wound telescopic masts from CompoTech (Sušice, Czech Republic) that, while they aren’t electronic devices in and of themselves, can be used for mounting and raising electronic and communications equipment, such as those mounted to Czech Republic Border Police regional mobile police vehicles to carry visual/acoustic surveillance and radio communication equipment.
Fiber-reinforced plastic (FRP) replacing coated steel in more reinforced-concrete applications.
Fast-reacting resins and speedier processes are making economical volume manufacturing possible.
The structural properties of composite materials are derived primarily from the fiber reinforcement. Fiber types, their manufacture, their uses and the end-market applications in which they find most use are described.