| abstract |
PROBLEM TO BE SOLVED: To recycle a polyurethane so that a polyurethane to be recycled for the production of a polyurethane can be introduced again into a production process without having to accept a loss of quality. SOLUTION: Polyurethane is crushed and reacted with one mixture in a first reaction step. From the crushed polyurethane, (a) a polyisocyanate, (b) a substance having active hydrogen and being reactive to isocyanate And (c) optionally producing a prepolymer in an amount of 0.1 to 40% by weight, based on the polyaddition mixture containing the chain extender and / or crosslinking agent, catalyst, blowing agent and conventional additives. This prepolymer is reacted in a second reaction step with water and optionally (c) to convert it to polyurethane. |