HEAT INSULATING MATERIAL AND MANUFACTURE THEREOF

PROBLEM TO BE SOLVED: To provide a thick heat insulating material which can be cut easily by a cutter knife in a field of building construction. SOLUTION: In this heat insulating material 1, a suitable number of slits are formed extending from at least one face 1a of the heat insulating material 1 to equal to or larger than one third of thickness of the heat insulating material 1, the dimension of the remaining part left undone being 20-60 mm deep, overall in the longitudinal direction and/or in the cross-direction of the heat insulating material 1, and a projecting part and/or a recessed part is formed overall in the longitudinal direction and/or in the cross-direction of the heat insulating material 1 on the opposite face of the heat insulating material 1 on an extension of the side wall 2b of the slit. According to the manufacturing method for the heat insulating material, a plate-like heat insulating material is molded by foaming by use of a metal mold where a projecting part and/or a recessed part is formed overall in the longitudinal direction and/or in the cross-direction of the heat insulating material 1, and then a heated heating wire is pressed from the opposite face to the face of the plate-like heat insulating material where the projected part and/or the recessed part is formed, or a slit 2 is formed in the heat insulating material 1 by cutting by a rotary saw.