Process for the production of polyurethane molded parts and their use

A process for the production of molded parts, blocks and cylinders, comprising:

• (1) adding and uniformly distributing
• b) a liquid binder containing reactive NCO groups and based on a mixture and/or reaction product of:
• i) aromatic and/or aliphatic polyisocyanates, and
• ii) polyols, to
• a) production residues from polyurethane rigid foam production and/or post-consumer parts based on polyurethane rigid foam,
• (2) adding the mixture from (1) to a tool,
• (3) introducing steam, optionally under pressure, into the tool for the production of the molded part, block or cylinder,
• (4) hardening the product, and
• (5) removing the resultant molded part, block or cylinder from the tool,
• wherein a) said polyurethane rigid foam comprises an open-cell foam with a density of 5 to 50 kg/m3 (measured according to DIN 53 420), a compressive strength of 0.05 to 0.2 Mpa (measured according to DIN 53 421) and an open cell content of more than 50% (determined, according to DIN ISO 4590-86).