Thermal insulation for sides and roof of refrigerated lorry - comprises sandwich construction panels with inner, e.g. polystyrene layer, polystyrene foam core and outer skin formed by free expansion of core

The thermal insulation of refrigerated lorries is sandwich construction material round the sides and roof; it consists of an inner layer, polyurethane foam core, and the dense skin formed in making the foam and which has a grained finish as the resin is allowed to foam unrestrictedly. The foam is pref. free from fluorchlorhydrocarbons and is a closed-cell type. The inner skin is pref. fully recycleable polystyrene. The cross-section of the vehicle body the outermost covering (1) of metal. The innermost side (2) is the outer layer of the sandwich and is e.g. polystyrene. The thermal insulation of the sides and roof is the foam which is produced by unrestricted expansion of a regulated quantity for the required thickness. Moreover this expansion forms the dense leather-like surface skin (4). The transition from side to roof has the inner skin (2) overlapping and the interfaces (6) of the two layers of foam lie directly against each other. The overlap is ultrasonically welded, using a suitably shaped sonotrode so that the outer edge join is tapered off. ADVANTAGE - The insulation sheets are large, stable and have an inner layer shaped to suit the vehicle. The thickness of the foam can be made as required and it has a sealed leather-like skin. The sheets can be made virtually joint-free for the sides and roof. The narrow space between the foam skin and the inner face of the exterior wall contains struts for the wall and its air gap provides insulation also. The roof and wall insulations are ultra-sonically welded together.