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AssigneeHecker und Krosch GmbH & Co. KG
InventorsKarl Krosch, Barthel Krosch, Michael Krosch, Robert Ecker
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The recycling of used polyurethane foam is made possible by a process in which the starting material is first dried to a moisture content of 2 to 4% and is then filled into a multi-part mold (16, 17, 18) that defines the molded part (32). The parts of the mold (16, 17, 18) are then, with generation of the necessary compression pressure of below 20 N/mm.sup.2, pressed together and locked. These molds (16, 17, 18) that are subject to the compression pressure are heated in a tunnel furnace (20) so that the molding material reaches a temperature of approximately 130.degree. C. After a predefined holding time, the molds (16, 17, 18) can be opened under pressure and the molded parts (32) can be removed. Molded parts (32) with a thickness of 42 mm and of corresponding size have been produced successfully with this process. Instead of the molds (16, 17, 18), it is also possible that a two-part tool is used. Also possible is the use of turntables (14, 41, 44), whereby the pressing and holding time can be shortened by adding an accelerator. The process, which comprises only one pressing step, enables an approximately continuous operation.
A method of recycling rigid polyurethane foam and producing molded pieces of pretreated rigid foam, comprising the steps of comminuting a starting product to greater than zero but less than about 10 mm, drying the starting product to approximately 2 to 4% residual moisture, mixing a binder with the starting product, filling multi-part molds with the mixed starting product and binder, locking and pressing the molds together by generating compression pressure, compressing the molds at greater than ambient but less than or equal to approximately 20N/mm.sup.2 while maintaining ventilation passages, heating the molds externally until the molds reach temperatures between approximately 80.degree. and 180.degree. C., keeping the molds closed for a predetermined holding time, and releasing molded pieces from the molds.
A method of recycling rigid polyurethane foam and producing molded pieces of pretreated rigid foam, comprising the steps of comminuting a starting product to less than about 4 mm but greater than 0 mm, drying the starting product to approximately 2 to 4% residual moisture, filling starting product in multi-part molds defining molded pieces, compressing the molds in a compression phase with approximately 2.5 to 5N/mm.sup.2 of pressure, maintaining the pressure for a predetermined holding time, heating the multi-part molds during the set holding time to a temperature not less than 80.degree. and not greater than 180.degree. C., and removing molded pieces from the molds.
An apparatus for processing rigid polyurethane foam, comprising a comminuting unit for receiving and pulverizing a starting product, an intermediate bunker for receiving and holding a pulverized starting product, a drying device combined with the intermediate bunker for drying the pulverized starting product, a mixing device for receiving a dried starting product and for mixing the dried starting product with a binder, and a molded part production device for molding a mixed starting product into a molded piece.
An apparatus for processing rigid polyurethane foam, comprising a comminuting unit, a presorting bunker for receiving a starting product from the comminuting unit, a metering screw connected to the bunker through which a sorted starting product is removed, a metering pump for receiving the sorted starting product and for adding a binder to the sorted starting product, a mixing device for receiving the mixed starting product from the metering pump, a drying device combined with the mixing device, and a press for receiving the dried starting product and for forming molded pieces.
Dependencies are inferred from the claim text.