Abstract: An improved protective helmet is made of a dual density, closed-cell, polymeric foam laminate. The inner layer is a lower density (3.8 to 5 pcf), closed-cell, polymeric foam for comfort, absorbing minor impacts and distributing impact stress over a larger surface of the skull to reduce injury. The outer layer is a higher density (5 to 7.2 pcf), closed-cell, polymeric foam to absorb major impacts and add structural stability to the helmet. Ventilation holes provide airflow through the helmet. Cushioning pads may be added inside the helmet for customizing fit and improving ventilation. The preferred material for the inner and outer layers of the laminated, dual density protective helmet is a nitrogen blown, cross-linked, closed-cell, polyethylene foam. The dual density, closed-cell, polymeric foam laminate of the helmet provides improved impact attenuation. The laminate also reduces the weight of the helmet, which improves comfort and reduces neck fatigue for the wearer.

Abstract: A highly flexible composite material having a flexible matrix containing a phase change thermal storage material. The composite material can be made to heat or cool the body or to act as a thermal buffer to protect the wearer from changing environmental conditions. The composite may also include an external thermal insulation layer and/or an internal thermal control layer to regulate the rate of heat exchange between the composite and the skin of the wearer. Other embodiments of the PCM composite also provide 1) a path for evaporation or direct absorption of perspiration from the skin of the wearer for improved comfort and thermal control, 2) heat conductive pathways within the material for thermal equalization, 3) surface treatments for improved absorption or rejection of heat by the material, and 4) means for quickly regenerating the thermal storage capacity for reuse of the material. Applications of the composite materials are also described which take advantage of the composite's thermal characteristics.