| 摘要 |
PROBLEM TO BE SOLVED: To delay and upgrade discoloration properties of an urethane foam by setting all color difference changes before and after an ultraviolet test, an Nox test, a heat test and a wet heat test under predetermined conditions of a cushioning material to specific values or less. SOLUTION: A film is laminated on one surface of a soft polyurethane foam to constitute the cushioning material. A numeric value for evaluating discoloration properties of the material is set to 7 or less for all color difference changes before and after an ultraviolet test at the time of conducting an ultraviolet ray illumination for 9 hours by using a carbon arc 1 lamp by a fade meter an Nox test at the time of exposure of a sample for two hours with 500 ppm Nox gas, a heat test at the time of heating a sample for two hours at 120 deg.C, and a wt heat test at the time of heating a sample for five days under conditions of 70 deg.C and 95% R.H.
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