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A method for producing a lightweight, sound insulating covering (1, 1′, 1″, 1″′) for a body component of a motor vehicle, in particular a lightweight dashboard covering, wherein the covering (1, 1′, 1″, 1″′) is produced as a foamed, sound absorbing molded part in a single-stage operation by injectin

A method for producing a lightweight, sound insulating covering (1, 1′, 1″, 1″′) for a body component of a motor vehicle, in particular a lightweight dashboard covering, wherein the covering (1, 1′, 1″, 1″′) is produced as a foamed, sound absorbing molded part in a single-stage operation by injecting a reactive mix, comprising polyol and isocyanate, into a cavity (11) of a foaming tool (9), wherein before and/or during the injecting, at least one predetermined surface portion (17), defining the cavity (11) of the foaming tool (9), is temperature-controlled in such a manner that the foamed molded part comprises an integral substantially pore free skin (1.1) with a thickness of at least 0.5 mm on one side, and comprises an open porous surface (1.2) and/or a thinner, sound permeable skin (1.4) on its side opposite to said skin (1.1).

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1. A method for producing a lightweight, sound insulating covering for a body component of a motor vehicle, in particular a lightweight dashboard covering, wherein the covering is produced as a foamed, sound absorbing molded part in a single-stage operation by injecting a reactive mix, comprising po

1. A method for producing a lightweight, sound insulating covering for a body component of a motor vehicle, in particular a lightweight dashboard covering, wherein the covering is produced as a foamed, sound absorbing molded part in a single-stage operation by injecting a reactive mix, comprising polyol and isocyanate, into a cavity of a foaming tool, wherein before or during the injecting, at least one predetermined surface portion , defining the cavity of the foaming tool, is temperature-controlled in such a manner that the foamed molded part comprises an integral substantially pore free skin with a thickness of at least 0.5 mm on one side, and comprises at least one of an open porous surface and a thinner sound permeable skin on its side opposite to said skin. 2. A method according to claim 1, wherein the at least one surface portion of the foaming tool, where the integral, substantially pore free skin of the foamed molded part can be produced, is cooled to a temperature in the range of 15° C. to 60° C. 3. A method according to claim 1, wherein the surface portion of the foaming tool, at which at least one of the open porous surface and the thinner sound permeable skin can be produced, is temperature controlled to a temperature in the range of 50° C. to 90° C. 4. A method according to claim 1, wherein the foaming tool is temperature-controlled in such a manner that between its surface portion, at which the integral substantially pore free skin of the foamed molded part can be produced, and its surface portion, at which at least one of the open porous surface and the thinner sound permeable skin can be produced, a temperature difference of at least 15° C. exists. 5. A method according to claim 1, wherein filler material is added to the reactive mix formed from polyol and isocyanate before injecting it into the foaming tool. 6. A method according to claim 5, wherein at least one of barium sulfate and calcium carbonate are added to the reactive mix as filler material. 7. A method according to claim 5, wherein carbon dioxide is added to the filler material. 8. A method according to claim 1, wherein the foaming tool comprises at least one protrusion disposed in the cavity, wherein said protrusion defines an opening in the molded part produced when the reactive mix is injected, wherein the at least one surface portion of the foaming tool, at which the integral, substantially pore free skin of the molded part can be produced, surrounds the protrusion at a distance. 9. A method according to claim 1, wherein the foaming tool comprises several cooled surface portions, offset from one another, so that the foamed molded part is produced with several integral skin portions, offset from one another, which are substantially pore free. 10. A method according to claim 1, wherein a material web section or a plastic foil blank, or a fibrous fleece blank, is inserted into the foaming tool at the at least one surface portion at which the integral substantially pore free skin of the foamed molded component can be produced, and injected from behind with the reactive mix, comprising polyol and isocyanate. 11. A lightweight, sound insulating covering for a body component of a motor vehicle, substantially comprised of a sound absorbing molded part, foamed in a one-step process, made of a soft open cell polyurethane foam, which comprises an integral substantially pore free skin with a thickness of at least 0.5 mm on one side, and which comprises at least one of an open porous surface and a thinner sound permeable skin on its side opposite to said skin. 12. A covering according to claim 11, comprising at least one opening, wherein an end of the opening is surrounded at a distance by the integral substantially pore free skin, and at least one of an open porous surface and a thinner sound permeable skin is configured between said skin and the opening. 13. A covering according to claim 11, comprising plural integral skin portions offset from one another and substantially pore free. 14. A covering according to claim 11, wherein the integral substantially pore free skin has a thickness of at least 1 mm. 15. A covering according to claim 11, whose total mass per unit area is less than 900 g/m2. 16. A covering according to claim 11, wherein its open porous sound absorbing portion comprises a raw density in the range of 0.02 to 0.06 g/cm3. 17. A covering according to claim 11, wherein its integral substantially pore free skin comprises a raw density in the range of 0.08 to 2.0 g/cm3. 18. A covering according to claim 11, whose sound permeable skin comprises a thickness of less than 400 μm. 19. A covering according to claim 11, which is configured in one piece. 20. A covering according to claim 11, whose integral substantially pore free skin is provided partially or on its entire surface with a cover layer, comprising a plastic foil, or a fibrous fleece material, wherein the integral skin is bonded to the cover layer through injecting from behind. 21. A covering according to claim 20, wherein the fibrous fleece material has a weight per unit area of 20 to 150 g/m2. 22. A covering according to claim 20, wherein the volume fleece material has at least one of a weight per unit area of 200 to 700 g/m2 and a thickness of 5 to 20 mm.