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.

Description

FIELD OF THE INVENTION[0001]The present invention generally relates to fire-resistant, bitumen-impregnated cellulose fiber sheets and their method of manufacturing. Said sheets are mainly intended to be used as covering material, and in particular, as roof covering material.PRIOR ART[0002]Bitumen-impregnated cellulose fiber sheets are well known by the one skilled in the art. They are generally manufactured from recycled paper and are rectangular in shape. Conventionally, the recycled paper is subjected to a processing step for removing the non-cellulosic elements, such as staples for example, and to a defibration step, before forming a paper pulp that will be applied on a wire, then let drain and calibrated. It is possible to add other elements to the pulp, such as pigments for example, in order to obtain colored cover sheets, adapted to the architectural environment. The cellulose fiber pulp may be corrugated by means of a machine as described in the patent FR 2,496,551 or in the ...

AI Technical Summary

Benefits of technology

The patent describes a fireproof coating that uses expandable graphite to protect inflammable materials from fire propagation and penetration. The coating is applied through gravity deposition or spray deposition, with the latter being preferred for a more homogeneous and fire-resistant layer. The coating is effective due to the endothermic combustion reaction of the expandable graphite, which forms an isolating barrier and reduces thermal conductivity. The coating also limits flame propagation and smoke production. The invention provides a natural, non-polluting, and fire-retardant agent that can be used in various applications such as bitumen and cellulose fibers.

Problems solved by technology

The absence of a high additional load therefore limits the structure reinforcements often required for renovation works.

However, their low resistance to an external fire poses a real problem regarding the security standards imposed by the national and international authorities, and in particular those imposed by the European Commission.

Indeed, such standards are in constant evolution and the requirements imposed are more and more severe.

However, the literature describes no fireproof coating for bitumen-impregnated cellulose fiber sheets.

Now, as mentioned above, these sheets offer many advantages in the field of construction but their low fire-resistance does not fulfill the standards imposed by the European authorities.