| abstract |
A urethane bumper spring is produced from a urethane raw material containing a polyester-based polyol as a polyol component and diphenylmethane diisocyanate as an isocyanate component, and includes: a skin layer; and a core portion, in which the skin layer has a density (Da) and a foamed cell diameter (Ra), and the core portion has a density (Db) and a foamed cell diameter (Rb). The density (Da), the foamed cell diameter (Ra), the density (Db), and the foamed cell diameter (Rb) satisfy relationships shown in the following expressions: 1.0≦Da/Db<1.34 (1) and 0.53<Ra/Rb≦1.0 (2). Accordingly, the urethane bumper spring can achieve a cost reduction while having durability and settling resistance under high load and high deformation. |