Flexible composite sheet and flexible seat cushion including the same

A flexible composite sheet, comprising:

• a flexible polymer film which is obtained by loading a masterbatch composition to develop color in a flexible polymer substrate, the masterbatch composition including
• a thermoplastic polymer,
• a yellow pigment component selected from the group consisting of Color Index (C.I.) Pigment Yellow 81, C.I. Pigment Yellow 83, C.I. Pigment Yellow 109, C.I. Pigment Yellow 110, C.I. Pigment Yellow 120, C.I. Pigment Yellow 128, C.I. Pigment Yellow 138, C.I. Pigment Yellow 147, C.I. Pigment Yellow 181, C.I. Pigment Yellow 183, C.I. Pigment Yellow 214, C.I. Pigment Brown 23, and combinations thereof,
• a red pigment component selected from the group consisting of C.I. Pigment Red 122, C.I. Pigment Red 144, C.I. Pigment Red 149, C.I. Pigment Red 166, C.I. Pigment Red 181, C.I. Pigment Red 202, C.I. Pigment Red 214, C.I. Pigment Red 221, C.I. Pigment Red 242, C.I. Pigment Red 254, C.I. Pigment Red 262, C.I. Pigment Orange 43, C.I. Pigment Orange 61, C.I. Pigment Orange 64, C.I. Pigment Orange 68, C.I. Pigment Orange 72, C.I. Pigment Violet 19, C.I. Pigment Violet 37, C.I. Pigment Violet 23, and combinations thereof, and
• a blue pigment component selected from the group consisting of C.I. Pigment Blue 15 series, C.I. Pigment Blue 16, C.I. Pigment Blue 60, C.I. Pigment Blue 80, and combinations thereof;
• and
• a metal film which is in intimate contact with a surface of the flexible polymer film;
• the flexible composite sheet having low heat build-up property.