Foamed article with absorbing characteristics on one side and non-absorbing characteristics on the other side and method for producing same
There is provided a multi-layered foamed article. The foam article has a layer of foam material on either side of an inner peel layer disposed roughly in the middle of the foam. The portion of the foam in closest proximity to the peel layer is subjected to the greatest amount of heat during extrusion forming mostly large open cell foam. The foam near the surface of the multiplayer foam article is cooled by the atmosphere or contact with cooling surfaces and comprises mostly small closed-cell foam. There is also provided a method for making a multi-layer foamed article by co-extruding an inner peel layer sandwiched between two expanded layers of a foam material. Each of the expanded foam layers on either side of the peel layer of the article is easily peeled or stripped from the peel inner layer and the multi-layer article is converted into a foamed article with absorbing characteristics on one side and non-absorbing characteristics on the other side. Thus, the foam is predominantly open-cell on one side of the structure and predominantly closed-cell on the opposing side. The open-cell portion of the article is highly absorbent and easily soaks up liquids. The closed cell portion of the foam article acts as a waterproof layer preventing liquid from moving all the way through the thickness of the foam. After blowing the polymer melt, the extrusion product comprises a foam article with a peel layer disposed roughly in the middle of the foam. A preferred embodiment of the multi-layer article is polystyrene foam for the two outer layers and a polyethylene film as the inner peel layer.
1. A multi-layer foam article comprising
a pair of extruded foam outer layers having open cells and closed cells, and an inner layer sandwiched between said pair of extruded foam outer layers, said pair of extruded foam outer layers being co-extruded with said inner layer and each extruded foam outer layer being predominantly open cell on one side and predominantly closed cell on the opposite side while the open cell side is adjacent to said inner layer, wherein said inner layer is capable of being readily separated from said extruded foam outer layers after extrusion and said closed cells form a waterproof layer.
2. The foam article according to claim 1 wherein said outer layers are at least one polymer is selected from the group consisting of a styrene polymer, a polyolefin polymer, a polyester, an ethylene/propylene terpolymer, polyvinyl chloride and polyphenylene oxide.
3. The foam article according to claim 1 wherein said outer layers are at least one polymer includes a styrene polymer selected from the group consisting of polystyrene, polystyrene copolymers, acrylonitrile/butadiene/styrene copolymer, styrene/maleic anhydride and high impact polystyrenes.
4. The foam article according to claim 1 wherein said inner layer is a polyethylene.
5. The foam article according to claim 1 wherein said foamed outer layer comprises at least 50% open cells.
6. The foam article according to claim 1 wherein the size of the pores in said open cells from about 0.005 inches diameter to about 0.020 inches in diameter.
7. The foam article according to claim 1 wherein the density of said foam is from about 0.05 g/cc to about 0.50 g/cc.
8. The foam article according to claim 1 wherein the foam has an average cell size of from about 0.05 inches diameter to about 0.10 inches in diameter, an overall open cell content of at least 50%, and a density of about 0.05 g/cc to about 0.50 g/cc.
9. A foam article with absorbing characteristics on one side and no-absorbing characteristics on the other side made by the process comprising:
(a) preparing a polymer melt with at least one polymer;
b) co-extruding a multi-layer structure having an inner layer and a pair of extruded foamed outer layers on either side of said inner layer, said extruding step cooling the outer surface of said extruded outer layers to form a pair of extruded foamed outer layers having at least 50% open cells and the remainder being closed cells with each extruded foam outer layer being predominantly open cell on one side and predominantly closed cell on the opposite side while the open cell side is adjacent to said inner laver with the open cells being adjacent said inner layer, wherein said inner layer is capable of being readily separated from said extruded foamed outer layers after extrusion, and said closed cells form a waterproof layer.