Abstract: A method of treating waste product containing flexible polyurethane resin includes adding a decomposing agent to the waste product to start a decomposition reaction; and terminating the decomposition reaction at a stage in which a diamine concentration derived from an isocyanate raw material of the flexible polyurethane resin is 2 wt % or lower to obtain a pasty intermediate product.

Abstract: The invention relates to a resin composition that has, as a raw material, a product that is obtained by addition reacting a compound having a unsaturated carbon bond to a resin decomposed product obtained by chemically decomposing a urethane resin, alternatively, by decomposing a urethane resin with a compound having a unsaturated carbon bond. The resin composition can be solidified by polymerization by use of a cross-linking agent and an addition polymerization initiator. Furthermore, when a compound having two or more carboxyl groups or an anhydride thereof is blended together with the urethane resin decomposition, a resin composition can be obtained. When the resin composition obtained thereby is cured, a recycled resin with excellent properties can be obtained.