Abstract: A corrugated board structure including an upper layer of corrugated board, a bottom film and a middle layer of PU foam. Each side of the bottom PVC film is formed with an inward bent upright folded wall which, during the foaming and expansion procedure of the PU foam, restricts the foaming space so as to continuously produce solid foam structure. The middle PU foam makes the upper and lower layers tightly adhered to each other as an integral body. An edge of the projection on one side and an edge of one of the front and rear ends is free from any PU foam and bottom film so that two adjacent corrugated boards can be overlaid and connected.

Abstract: A method of producing and the product of heat-proof laminate boards are disclosed. Each laminate board cut from a continuous laminate has a corrugated upper layer, a middle foam layer produced by spraying foam agent onto one side of the upper layer which will expand into shape automatically, a bottom layer having opposite edges folded in conformance to the corresponding edges of the upper layer so as to sealedly confine the foam in between the upper layer and bottom layer. The upper layer can be made of one of the materials including steel plate, PVC, PC, PP, aluminum plate, iron sheet. The bottom layer is made of materials including PVC film, PP film, papery film, fabric film, nylon film or wooden fiber sheet.