Polyisocyanurate coverboards with improved fire resistance

Abstract

A construction board comprising a foam body having first and second planar surfaces, said foam body including a polyisocyanurate foam matrix defining a plurality of closed cells, said closed cells being at least substantially devoid of hydrocarbon blowing agents, and said foam body being characterized by a density, pursuant to ASTM C303, of at least 2.5 lbs / ft3; and a facer disposed on a planar surface of said foam body, said facer including a glass substrate having an internal planar surface proximate to said foam body and an external planar surface opposite said foam body, a first coating disposed on said external surface, and a second coating disposed on or proximate to said internal surface, where said first coating disposed on said external surface includes an inert filler, and where said second coating disposed on or proximate to said internal surface includes intumescent material.

Description

[0001]This application claims the benefit of U.S. Provisional Application Ser. No. 62 / 501,802 filed on May 5, 2017, which is incorporated herein by reference.FIELD OF THE INVENTION[0002]Embodiments of the present invention are directed toward composite high density polyisocyanurate cover boards that have improved fire properties due, at least in part, to the absence of a hydrocarbon blowing agent and the presence of a glass facer that includes an external coating including inert filler and an interfacial coating including intumescent material.BACKGROUND OF THE INVENTION[0003]Coverboards and recovery boards are often used in commercial roofing systems to provide roofs with fire barrier properties, protection from foot traffic, and protection from environmental forces such as hail. A commonly used coverboard is a fiberglass faced gypsum board, which is sold under the tradename DENSDECK. Notably, these boards have found wide acceptance because they are noncombustible, per ASTM E136, ha...

AI Technical Summary

Benefits of technology

The invention provides a construction board made of foam with a facer made of a glass substrate and two coatings. The first coating is on the external surface and contains an inert filler, while the second coating is on the internal surface and contains intumescent material. The foam is characterized by a density of at least 2.5 lbs / ft3, which results in a lightweight yet strong insulation material.

Problems solved by technology

While fire resistant and dimensionally stable, these construction boards have appreciable weight and structure, which impacts transportation, movement on a job site, and overall ease of installation.

While polyisocyanurate coverboards and recover boards are widely used in the industry, they do not meet all of the standards, especially those related to flame resistance, that have been achieved by fiberglass faced gypsum board.

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