Extrusion coating method with polyolefin foam
AssigneeSumitomo Chemical Company, Limited
InventorsNobuo Fukushima, Takayoshi Adachi, Nobuyuki Takahashi, Kazuaki Sakakura
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Abstract
Disclosed is a method for continuous extrusion coating of a hollow core material with a highly expanded polyolefin resin, which is characterized by subjecting an extruded molten mass of an expandable polyolefin resin to external cooling at the point at which said molten mass begins to foam and supplying said hollow core material with the surface temperature thereof kept below the softening point of said polyolefin resin for thereby enhancing the fastness of adhesion of the highly expanded polyolefin foam with the hollow core material and at the same time facilitating the release of the two materials thus joined.
Claims6
In a method for the continuous extrusion coating by the use of a coating die of a hollow core material with a highly expandable polyolefin resin composition containing a volatile organic liquid blowing agent, the improvement comprising externally, cooling the outer surface of said extruded molten mass of expandable polyolefin resin, at the point at which said molten mass begins to foam, by by contacting said surface with a cooling gas or water to allow the pressure of foaming to be exerted inwardly and also to cause the growth of foam to proceed in the direction of the internal core for thereby enabling the polyolefin foam to adhere fast to the hollow core and giving rise to a coating having a smooth surface condition, wherein said expanded polyolefin foam has an expansion ratio of not less than 3.
Dependencies are inferred from the claim text.