| 摘要 |
PROBLEM TO BE SOLVED: To provide a composite foam which uses only a resin but not an inorganic fiber such as glass fiber and shows outstanding mechanical physical properties such as compression strength, bending strength, creep resistance and elastic recovery power and hardly gives rise to a phenomenon such as warpage or permanent strain, with other advantages such as elastic restoration to an original shape, even when the foam is slightly deformed and consequent keeping of flatness, superb dimensional stability, lightweight and almost no fear about undesireable influence upon a human body and the environment, and a tatami core consisting of the foam and a thin tatami constituted of this tatami core. SOLUTION: This composite foam 1 constituted of a polyolefin resin sheet which is stretched 5 to 20 times as much and 100 to 2,000μm thick and shows that a strain at the limits of bending elasticity is 0.2% or more, laminated on at least one of the sides of a polyolefin resin foam sheet showing that an average value of the aspect ratio Dz/Dxy of an internally existing cell is 1.1 to 4.0 and the expansion ratio is 3 to 20 times. The thin tatami uses the foam 1 as a tatami core.
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