Characteristics and Attributes of Char Forming Combustion Modified Flexible Foams Based on PHD Polyol

Abstract

Combustion modified foams have been used in various applica tions for several years and they can be formulated to meet a variety of flam mability standards. Two general groups are commercially established: foams having margmal fire retardancy and foams having a high degree of resistance to ignition when exposed to high energy open flames such as two sheets of burning paper. The latter include melamine modified HR foams, which drip and develop molten polymer upon flame exposure, and the hydrate alumina modified HR foams that form a surface char upon flame exposure that protects the foam underneath against burning and reduces the rate of fire growth in fur nishings. Several types of latter foams have been developed, namely: high per formance COMBUSTION MODIFIED HIGH RESILIENCE (CMHR) foams that contain a sophisticated flame retardant system comprised of hydrated alumina and auxiliary flame retardants; MRC high resilience foams for medium risk category occupancies which also contain hydrated alumina and flame retardants; and ATH/HR that perform within the range bounded by Cali fornia 117 foams and CMHR foam—they are high resilience foams that contain only hydrated alumina and a liquid flame retardant. All of these are char formers-a very important attribute for fire safety in furnishings, transit vehicle seating, and other applications.

Since all of the said char forming combustion modified foams based on PHD polyol contain organic materials, they are subject to decomposition and igni tion, and will sustain burning when exposed to a sufficiently intense heat source. Nevertheless, all of them represent a significant contribution to im proved fire safety in the end applications.

Combustibility tests were conducted using specified controlled tests to measure the performance behavior of the material under these conditions. The data are not intended to reflect the hazards of this or any other material under actual fire conditions. This paper emphasizes the importance of char forming characteristics of foam in fire performance.

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