Conductive Plastics Stop Toys from Interfering
November 7, 2011

A proliferation in the number and variety of electronic and electrical toys on the market has brought with it the growing problem of electromagnetic interference.

Not only are emissions from toys such as video games interfering with other electronic equipment, but they can also affect the functioning of the toy itself. So far, toy manufacturers have shied away from seeking a high tech solution to the problem because of the low cost of products in the market.

Now, however, researchers at Spain’s Toy Research Institute (AIJU) have come up with a solution to this problem through the materials used to make such products. They are developing conductive plastics, incorporating carbon nanofibers, which will considerably reduce any magnetic interference.

A five-strong team at AIJU, based in the Spanish toy industry center of Ibi, is undertaking a two year research and development project to tackle the interference problem. They are combining carbon nanofibers with polyethylene and polypropylene, polymers commonly used in toy production, to assist electrostatic dissipation, electrostatic painting and electromagnetic outer screening.

To achieve the aims of the program, it was essential the resulting materials were lightweight, capable of being extruded and injection molded and able to resist a magnetic and electrical field, as well as being cost competitive.

During the first year of AIJU’s EMIToy project, which saw investment of around 95,000 euros, the materials specialists achieved encouraging results. Tests incorporating carbon nanofibers and carbon black in a composite material significantly reduced the levels of electromagnetic percolation to below 2 percent, according to project manager Ana Ibáñez.

“Immediately, the degree of resistance is in the region of 1,000 ohm cm. Probably, with 8 percent concentration of [carbon] nanofibers and 12 percent of carbon black we could reach effective electromagnetic screening,” she told European Plastics News.

In the second year of the EMIToy project, the Spanish team has been working with a base PP matrix incorporating an 8 percent carbon black content, prepared in a twin-screw co-rotating extruder. This formed the base material for trials with varying quantities of carbon nanofibers: 2 percent, 4 percent and 6 percent. Similar tests are being carried out with a high density polyethylene substrate.

Once the team from AIJU’s Product Engineering Laboratory has determined the optimum percentage content and type of nanofibers, it will design a suitable plastic housing component for the chosen electronic toy using the best conductive material.

Already, a number of companies in the Spanish toy industry and from other sectors have expressed interest in the results of the project, which is due to be completed by the end of this year, Ibáñez says.

The EMIToy project is being financed by IMPIVA, the Valencia region’s Institute of Small and Medium Sized Enterprises, and the European Regional Development Fund (ERDF).