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US 5,196,247 AGranted
Compostable polymeric composite sheet and method of making or composting same
AssigneeClopay Corporation
InventorsPai-Chuan Wu, Thomas R. Ryle, Leopoldo V. Cancio
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Abstract
Compostable polymeric sheets of biodegradable or environmentally degradable polymers are disclosed. These composite sheets may be made by extrusion and are compostable in municipal solid waste treatment facilities.
Claims21
A compostable polymeric composite sheet comprising
- a water insoluble and impermeable top film of thermoplastic polymer,
- a water insoluble bottom layer of thermoplastic polymer and
- an intermediate film of water soluble polymer for bonding said top film and bottom layer together to form said composite sheet, each of said films or layer being biodegradable or environmentally degradable, said water soluble film facilitating the separation of the composite in the presence of water for exposure of the top film and bottom layer to enhance degradation,
- wherein said sheet is formed by coextrusion of said top film and said intermediate film, said top film has a plurality of post-extruded stretched areas along lines spaced substantially uniformly across the film surface areas and through the depth of the film, said stretched areas being separated by unstretched areas and having a thickness less than the unstretched areas, said stretched areas for weakening said film to further enhance its degradation while maintaining its water impermeability.
1 more element
A water impermeable compostable composite polymeric backsheet for diapers and sanitary pads comprising
- a water insoluble and impermeable top film of thermoplastic polymer,
- a water insoluble bottom layer of thermoplastic polymer and
- an intermediate film of water soluble polymer for bonding said top film and bottom layer together to form said composite sheet, each of said films or layer being biodegradable or environmentally degradable, said water soluble film facilitating the separation of the composite of the presence of water for exposure of the top film and bottom layer to enhance degradation, said composite having a thickness of about 0.5 to about 10 mils,
- wherein said sheet is formed by coextrusion of said top film and said intermediate film of water soluble polymer, said sheet having a plurality of post-extruded stretched areas along lines spaced substantially uniformly across the sheet surface areas and through the depth thereof, said stretched areas being separated by unstretched areas and having a thickness less than the unstretched areas, said stretched areas for weakening said sheet to enhance its degradation while maintaining its water impermeability.
1 more element
Dependencies are inferred from the claim text.