Multilayer plastic bottles with mineral filler and foamed layer for improved recyclability

Abstract

Plastic containers exhibiting reduced plastic resin usage, while maintaining a specific gravity of below 1.0, so as to allow their quick and easy separation using floatation techniques during recycling. Within a layer or portion some of the plastic resin of the container body may be replaced with an inorganic mineral filler material, while within another layer or portion of the plastic container, the plastic material (e.g., polyethylene, polypropylene) may be foamed. The fraction of mineral filler material that may be included within the polyethylene may thus be increased beyond that previously possible while maintaining the specific gravity below 1.0, by also foaming a layer or portion of the polymeric material, so as to create voids therein. This allows significantly less resin material to be employed, while maintaining strength characteristics of the plastic container so as to be at least comparable to existing plastic containers not including such mineral filler materials.

1 . A plastic container comprising:
 (a) an exterior first layer, the first layer comprising polyolefin;   (b) an interior second layer, the second layer comprising polyolefin;   (c) an interior third layer, the third layer comprising polyolefin;   (d) wherein at least one of the layers comprises at least one of post-consumer or post-industrial recycled material;   (e) wherein at least one of the layers comprises foamed polyolefin;   (d) wherein at least one of the layers has a mineral filler material which is included in an amount of at least 5% by weight of the layer in which it is included, and a specific gravity of all the layers of the plastic container combined together is greater than 0.90 and below 1.0.   
     
     
         2 . The plastic container of  claim 1 , wherein the mineral filler material is included in sufficient amount that the specific gravity of all of the layers of the plastic container combined together would be greater than 1.0 if none of the layers comprised foamed polyolefin. 
     
     
         3 . The plastic container of  claim 1 , wherein at least one of the layers including polyolefin and the mineral filler material has a specific gravity above 1.0, and the foamed polyolefin layer has a specific gravity below 1.0, so that the specific gravity of all the layers of the plastic container combined together is below 1.0. 
     
     
         4 . The plastic container of  claim 1 , wherein the specific gravity of all the layers of the plastic container combined together is greater than 0.95 and below 1.0. 
     
     
         5 . The plastic container of  claim 1 , wherein the foamed polyolefin layer includes no mineral filler material, so that any layers including the mineral filler material are not foamed. 
     
     
         6 . The plastic container of  claim 1 , wherein the mineral filler material is selected from the group consisting of calcium carbonate, talc, and combinations thereof. 
     
     
         7 . The plastic container of  claim 1 , wherein two or more of the layers include the mineral filler material dispersed within the polyolefin. 
     
     
         8 . The plastic container of  claim 7 , wherein the mineral filler material is included in an amount of at least 5% by weight of each of the two or more layers. 
     
     
         9 . The plastic container of  claim 1 , wherein the mineral filler material is included in an amount of at least 8% by weight in one or more of the layers. 
     
     
         10 . The plastic container of  claim 1 , wherein the mineral filler material is included in an amount of at least 10% by weight in one or more of the layers. 
     
     
         11 . The plastic container of  claim 1 , wherein the mineral filler material is included in an amount of at least 8% by weight of a body of the plastic container as a whole. 
     
     
         12 . The plastic container of  claim 1 , wherein the container is a blow-molded container. 
     
     
         13 . The plastic container of  claim 1 , wherein the container comprises a blow-molded container body and an injection molded container lid. 
     
     
         14 . The plastic container of  claim 1 , wherein the foamed polyolefin comprises from about 1% to about 20% voids by volume. 
     
     
         15 . The plastic container of  claim 1 , wherein the post-consumer or post-industrial recycled material comprises from about 10% to about 60% of a layer by weight. 
     
     
         16 . The plastic container of  claim 1 , wherein one or more of the layers comprises a colorant. 
     
     
         17 . A plastic container comprising:
 (a) an exterior first layer, the first layer comprising polyethylene and a colorant;   (b) an interior second layer, the second layer comprising polyethylene;   (c) an interior third layer, the third layer comprising polyethylene; and   (d) an interior fourth layer comprising polyethylene;   (e) wherein at least one of the layers has a mineral filler material, at least one of the layers comprises at least one of post-consumer or post-industrial recycled material, the polyethylene of at least one of the layers is foamed; and   (f) wherein a specific gravity of the plastic container is greater than 0.90 and below 1.0.   
     
     
         18 . The plastic container of  claim 17 , wherein the recycled material and the mineral filler are disposed within the same layer. 
     
     
         19 . The plastic container of  claim 17 , wherein the first layer includes the colorant and the mineral filler, the second layer includes the mineral filler, the third layer includes the recycled material, and the foamed layer is sandwiched between two other layers. 
     
     
         20 . A plastic container comprising:
 (a) a container body including at least one layer comprising polyethylene;   (b) wherein at least a portion of the container body comprises foamed polyethylene;   (c) wherein the container body includes a mineral filler in an amount that is sufficient so that the specific gravity of the plastic container would be greater than 1.0 without the foamed polyethylene, and is greater than 0.90 and below 1.0.