Influence of coating additives on intumescent high performance fire protection coatings for wood: Fid-Bau Portal

Influence of coating additives on intumescent high performance fire protection coatings for wood

Keton, Mohd Yusof Bin / Kruse, Dirk / Deppe, Barbora

Intumescent fire retardant coatings reduce the flame spread and the fire risk through the formation of a voluminous and insulating protective layer through carbonization and simultaneous foaming. The main function of an intumescent fire retardant coating is to shield the underlying substrate against the transfer of heat flux (radiation, convection and conduction) during the development phase of a fire. The standard intumescent system consists of three important elements which are inorganic acid (dehydrating agent), a polyhydric material rich in carbon (carbonific or char former) and a blowing agent (a spumific). General processes of intumescent mechanism are: 1) Softening of the binder/polymer, 2. Release of an inorganic acid (from ammonium polyphosphate), 3) Carbonization (e.g. of polyalcohol), 4. Gas formation by the propellant (e.g. melamine), 5) Foaming of the mixture, 6) Solidification. In this article, the influence of different combinations of coating additives on the char strength and the fire protection performance is discussed. One hypothesis was made which stated that sufficient mechanical properties in particular the strength of the char layer are influenced by additives e.g. adhesion promoters, anti crater and flow additives and wetting and dispersing additives etc. needed for the formulation of a coating system. To evaluate this hypothesis, the effect of these additives on the performance of an intumescent fire protection coating was investigated. The investigations were performed using a base formulation which has been developed at the Wilhelm-Klauditz Institut (WKI).