Fire-resistant cellulose-bitumen roofing sheet and method of manufacturing

Abstract

Bitumen-impregnated cellulose fiber sheets include on one of their main surfaces, an adhesive primer layer, and, deposited on this adhesive primer layer, a fireproof coating including expandable graphite. In a preferred embodiment of the invention, the expandable graphite has a trigger temperature lower than 300° C. and the layer of expandable graphite corresponds to a dry matter basis weight of 80 to 140 g/m2. The sheets have a fire resistance fulfilling in particular the European Standard EN 13 501-5. They are mainly intended to be used as covering material, and in particular, as roof covering material.

1 . A bitumen-impregnated cellulose fiber sheet, comprising on at least one of its main surfaces an adhesive primer layer, characterized in that a fire proof coating comprising expandable graphite is deposited on this adhesive primer layer. 
     
     
         2 . The bitumen-impregnated cellulose fiber sheet according to  claim 1 , characterized in that it includes corrugations. 
     
     
         3 . The bitumen-impregnated cellulose fiber sheet according to  claim 1 , characterized in that the expandable graphite has an expansion coefficient higher than 120 cm 3 /g at 600° C. 
     
     
         4 . The bitumen-impregnated cellulose fiber sheet according to  claim 1 , characterized in that the expandable graphite has a trigger temperature lower than 300° C. 
     
     
         5 . The bitumen-impregnated cellulose fiber sheet according to  claim 1 , characterized in that the expandable graphite has a trigger temperature ranging from 160° C. to 220° C. 
     
     
         6 . The bitumen-impregnated cellulose fiber sheet according to  claim 1 , characterized in that the mean dry matter basis weight of expandable graphite varies from 80 to 140 g/m 2 . 
     
     
         7 . The bitumen-impregnated cellulose fiber sheet according to  claim 1 , characterized in that the local dry matter basis weight of expandable graphite is at least of 80 g/m 2  in any point having a developed surface ranging from 1 cm 2  to 900 cm 2 . 
     
     
         8 . The bitumen-impregnated cellulose fiber sheet according to  claim 7 , characterized in that the local dry matter basis weight of expandable graphite is at least of 80 g/m 2  in any point having a developed surface ranging from 1 to 2 cm 2 . 
     
     
         9 . The bitumen-impregnated cellulose fiber sheet according to  claim 1 , characterized in that it includes a layer of paint deposited on the fireproof coating. 
     
     
         10 . A method of manufacturing a bitumen-impregnated cellulose fiber sheet according to  claim 1 , comprising (a) depositing an adhesive primer on at least one of the main surfaces of the bitumen-impregnated cellulose fiber sheet, (b) depositing through dry deposition, on the adhesive primer layer, a fireproof coating comprising expandable graphite. 
     
     
         11 . The method according to  claim 10 , further comprising (c) depositing a layer of paint on the fireproof coating. 
     
     
         12 . The method according to  claim 10 , characterized in that the fireproof coating is deposited by fluidized bed spray deposition. 
     
     
         13 . The method according to  claim 10 , characterized in that the fireproof coating is deposited by hopper deposition. 
     
     
         14 . The method according to  claim 13 , characterized in that the fireproof coating is deposited through a hopper equipped, at the lower end, with a knurled roll. 
     
     
         15 . Method of covering a roof which comprises: providing a bitumen-impregnated cellulose fiber sheet according to  claim 1 ; and applying said sheet to the roof as a roof covering material. 
     
     
         16 . The bitumen-impregnated cellulose fiber sheet according to  claim 2 , characterized in that the expandable graphite has an expansion coefficient higher than 120 cm 3 /g at 600° C. 
     
     
         17 . The bitumen-impregnated cellulose fiber sheet according to  claim 2 , characterized in that the expandable graphite has a trigger temperature lower than 300° C. 
     
     
         18 . The bitumen-impregnated cellulose fiber sheet according to  claim 2 , characterized in that the mean dry matter basis weight of expandable graphite varies from 80 to 140 g/m 2 . 
     
     
         19 . The bitumen-impregnated cellulose fiber sheet according to  claim 2 , characterized in that the local dry matter basis weight of expandable graphite is at least of 80 g/m 2  in any point having a developed surface ranging from 1 cm 2  to 900 cm 2 .