To prevent separation of the bond between urethane film and urethane foam even if air in a mattress is expanded due to an increased temperature in a mattress in which urethane film is bonded on all over the surface of urethane foam.
In the mattress 1 in which the urethane films 3a and 3b are bonded on all over the surface of the urethane foam 2, the urethane film 3a is bonded to the urethane foam 2 with a bonding area increased by 5-30 % under tension. After relieving the tension, at least the urethane film 3a on the upper surface or the lower surface is formed with an uneven shrunk pattern d. Therefore, tension on the urethane film 3a is reduced by elongation of the shrunk part of the urethane film 3a or by deflation from gaps h between the urethane film 3a and the side urethane film 3b, even when the air in the inner space is expanded with a rise in temperature.
KONISHI SUEO
TSUTSUI SHIGETAKA
