| 摘要 |
PROBLEM TO BE SOLVED: To provide a core material capable of eliminating the settling phenomenon caused by the weight of a user and capable of keeping excellent cushioning properties possessed by urethane foam over a long period of time. SOLUTION: The core material 1 is constituted by impregnating the surface of a flat panel comprising urethane foam 2 with a urethane emulsion liquid to form a cured layer 3 harder than the urethane foam 2. |
