PURPOSE: To obtain a crosslinked polyolefin foam, having small compression set arid capable of being readily incinerated by adding and mixing a highly elastic material with a polyolefin in a method for mixing the polyolefin with an inorganic compound, a foaming agent and a crosslinking agent, heating and expanding the resultant mixture.
CONSTITUTION: A crosslinked foam capable of being readily incinerated is produced by kneading (A) 100 pts.wt. polyolefin with (B) 1-60 pts.wt., preferably 3-50 pts.wt. highly elastic material (preferably ethylene-propylene copolymer or ethylene-propylene terpolymer), (C) 10-200 pts.wt., preferably 50-150 pts.wt. inorganic compound (preferably heavy calcium carbonate) having the surface optionally treated with a fatty acid-based, a silane-based or a titanium-based coupling agent, etc., (D) a crosslinking agent (e.g. dicumyl peroxide or tert-butyl peroxybenzoate) and, as necessary, a crosslinking assistant and (E) 2-30 pts.wt. foaming agent (e.g. azodicarbonamide), providing an expandable crosslinkable composition, then heating the resultant composition and decomposing the components (D) and (E).