The present invention relates to a web of closed cell foamed material made from soft plastic, the foamed material having essentially parallel upper and lower surfaces.
Webs of foamed material of the above-mentioned type have long been known in the art. When such webs are prepared from cross-linked polyolefins, they are completely inert, can still be formed after a prior heating, have excellent spring-back elasticity and exhibit a substantial heat insulating capacity. As a result of these properties, webs of closed cell foamed material made from cross-linked polyolefins have found diverse applications in the automotive field, in the field of insulation, in the manufacture of toys, camping equipment, sport articles, packing material, seat coverings, apparel and orthopedic products, advertising and display articles and in the building construction industry. However, these webs of foamed material exhibit the disadvantage of possessing low permeability to heat, moisture and sound and it is difficult, if not impossible, to achieve any degree of control or improvement in these properties. For example, while it may be possible to alter these properties by embedment of suitable materials in the foamed web, the closed cell or closed pore structure of the web prohibits such embedment. Even where it is possible to arrange that the web of foamed material originally contain alterations designed to improve these properties, the application of heat and pressure in forming the finished web results in a densification of the pore structure which frequently disadvantageously affects the originally set properties.