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Multi-layered fire door and method for making the same

  • US 7,721,500 B2
  • Filed: 01/23/2007
  • Issued: 05/25/2010
  • Est. Priority Date: 10/31/2002
  • Status: Expired due to Term
First Claim
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1. A door comprising:

  • a porous layer having two opposing major surfaces;

    at least three fire-retardant layers each comprising a fiberboard and coupled with the porous layer in an unbalanced construction, wherein a number of the at least three fire-retardant layers disposed on one of the two opposing major surfaces of the porous layer is greater than a number of the at least three fire-retardant layers disposed on another one of the two opposing major surfaces of the porous layer;

    a first exterior layer; and

    a second exterior layer, wherein the first exterior layer is coupled with one of the at least three fire retardant layers and the second exterior layer is coupled with another one of the at least three fire-retardant layers.

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