Thermoplastic article having portions with different fire resistances

Abstract

The parts of a pallet or other article have different tailored thermoplastic composition to provide fire resistance according to the shape, location and function of the part in the pallet. In one embodiment, the high surface area to volume deck has high fire retardant content, whereas the heavier portions of the pallet, such as the base and columns have lower content. In another embodiment, the periphery of the deck that is prone to impact damage has low retardant content, compared to the rest of the deck and or the rest of the pallet.

1 . A thermoplastic article comprising a plurality of thermoplastic portions, wherein at least two of said portions have differential fire resistance, by virtue of compositions or coatings, according to the position or geometry of said portions.  
   
   
       2 . A thermoplastic article in accordance with  claim 1 , wherein at least one said portion is thinner or has a higher surface area to volume ratio relative to another of said portions.  
   
   
       3 . A thermoplastic article in accordance with  claim 1 , wherein said thermoplastic article is a plastic pallet.  
   
   
       4 . A thermoplastic article in accordance with  claim 3 , wherein a deck of the pallet has higher fire retardant content than columns upon which the deck is mounted.  
   
   
       5 . A thermoplastic article in accordance with  claim 3 , wherein part or all of the periphery of a deck has less retardant or no retardant, compared to the interior of the deck which has fire retardant.  
   
   
       6 . A thermoplastic article in accordance with  claim 3 , wherein said pallet has a top deck spanning columns, wherein said deck comprises a top layer having less fire retardant than a bottom layer.  
   
   
       7 . A thermoplastic article in accordance with  claim 3 , wherein part of all of the sides of said pallet has less retardant or no retardant, compared to an interior portion of said pallet.  
   
   
       8 . A thermoplastic article in accordance with  claim 7 , wherein those portions of a pallet that are configured adjacent contact points for the tines of a forklift have less fire retardant than other portions of the pallet.  
   
   
       9 . A thermoplastic article in accordance with  claim 3 , wherein a first portion of said pallet has fire retardant content of between about 0 and 10 weight percent, and a second portion has a fire retardant content of between about 10 and 30 weight percent.  
   
   
       10 . A thermoplastic article in accordance with  claim 4 , wherein said deck has between about 8 to 12 weight percent fire retardant, and wherein said columns have between about 3 to 7 weight percent fire retardant.  
   
   
       11 . A thermoplastic article in accordance with  claim 3 , wherein the pallet includes a plate covering a reinforcing cross beam, and wherein said plate contains little or no fire retardant compared to other portions of the pallet.  
   
   
       12 . A thermoplastic article in accordance with  claim 3 , wherein an interior portion of a pallet deck has a first level of fire retardant, which is higher than the level of fire retardant in an edge component, such that the edge component has higher impact resistance relative to the interior portion.  
   
   
       13 . A thermoplastic article in accordance with  claim 3 , wherein a pallet deck has a gradually varying fire retardant composition across a horizontal section of the pallet deck.