Method for producing hollow plastic bodies by means of a heated molding tool, which forms a cavity, comprising the following method steps: a. providing a material composite consisting of i. a panel or sheet-like first layer of a first thermoplastic synthetic material, ii. a panel or sheet-like second layer of a second synthetic material, iii. a panel-like, open-cell or mixed-cell foam layer of a third synthetic material disposed between the first and the second layer (10,20), b. feeding the material composite to the opened cavity of a heated molding tool, and c. closing the molding tool, wherein i. pressure is applied onto the material composite at least in some sections such that, in the pressurized sections, the first and/or second layer (10, 20) is thermoformed and the foam layer is compressed, which results in a permanent deformation, at least of the first layer and/or the second layer (10, 20) and of the foam layer, ii. the first and/or second layer (10, 20), in the molding tool, detaches partially from the foam layer in such a way that the foam layer is in mechanical contact with the first or/and second layer (10, 20) substantially only in the compressed sections, iii. an air or gas-filled void, which is sealed on all sides, forms in the areas without mechanical contact, wherein the air or gas, which apart from the remaining foam layer fills the voids created, stems to a substantial extent from the pores in the compressed areas of the open-cell or mixed-cell foam layer. a. providing a material composite consisting of i. a panel or sheet-like first layer of a first thermoplastic synthetic material, ii. a panel or sheet-like second layer of a second synthetic material, iii. a panel-like, open-cell or mixed-cell foam layer of a third synthetic material disposed between the first and the second layer (10,20), i. a panel or sheet-like first layer of a first thermoplastic synthetic material, ii. a panel or sheet-like second layer of a second synthetic material, iii. a panel-like, open-cell or mixed-cell foam layer of a third synthetic material disposed between the first and the second layer (10,20), b. feeding the material composite to the opened cavity of a heated molding tool, and c. closing the molding tool, wherein i. pressure is applied onto the material composite at least in some sections such that, in the pressurized sections, the first and/or second layer (10, 20) is thermoformed and the foam layer is compressed, which results in a permanent deformation, at least of the first layer and/or the second layer (10, 20) and of the foam layer, ii. the first and/or second layer (10, 20), in the molding tool, detaches partially from the foam layer in such a way that the foam layer is in mechanical contact with the first or/and second layer (10, 20) substantially only in the compressed sections, iii. an air or gas-filled void, which is sealed on all sides, forms in the areas without mechanical contact, wherein the air or gas, which apart from the remaining foam layer fills the voids created, stems to a substantial extent from the pores in the compressed areas of the open-cell or mixed-cell foam layer. i. pressure is applied onto the material composite at least in some sections such that, in the pressurized sections, the first and/or second layer (10, 20) is thermoformed and the foam layer is compressed, which results in a permanent deformation, at least of the first layer and/or the second layer (10, 20) and of the foam layer, ii. the first and/or second layer (10, 20), in the molding tool, detaches partially from the foam layer in such a way that the foam layer is in mechanical contact with the first or/and second layer (10, 20) substantially only in the compressed sections, iii. an air or gas-filled void, which is sealed on all sides, forms in the areas without mechanical contact, wherein the air or gas, which apart from the remaining foam layer fills the voids created, stems to a substantial extent from the pores in the compressed areas of the open-cell or mixed-cell foam layer.