Densified foam for thermal insulation in electronic devices

A heat spreading and insulating material using densified foam is provided that has a heat spreading layer that is adhered to an insulating layer. The material is designed to be used with mobile devices that generate heat adjacent to heat sensitive components. The insulating layer is formed from a compressed layer of polyimide foam to increase its density. The polyimide foam retains a significant amount of insulating properties through the densification process. In some embodiments, an EMI shielding layer is added to improve electrical properties of the device. The heat spreading layer is commonly a graphite material with anisotropic heat properties that preferentially conduct heat in-plane. The material may also include pressure sensitive layers to permanently apply the material to the mobile device.