What is flame retardant foam

“Flame-retardant foam” refers to a polyurethane foam sealant with the ability to prevent or slow the spread of flames. It combines the excellent filling, sealing, bonding, thermal insulation, and sound insulation properties of conventional foam with the added benefit of critical fire safety features.

The following are its core features and related information:

Basic Properties (same as conventional foam):

Foam Expansion: It is a liquid or paste when extruded from a pressure can. Upon contact with air, it rapidly expands and solidifies, filling gaps, voids, and cavities, expanding up to several dozen times.

Adhesion and Sealing: After curing, it forms a closed-cell foam structure with excellent bonding (bonding to a variety of building materials such as concrete, brick, wood, metal, and plastic) and sealing properties (waterproofing, dustproofing, sound insulation, and thermal insulation).

Wide Applications: It is primarily used for caulking and sealing joints in building door and window installations, sealing wall holes, sealing pipe penetrations, bonding and caulking insulation panels, and performing home repairs.

Core Differentiation – Flame Retardancy:

Added Flame Retardants: Specific flame retardants are added to the polyurethane raw materials during the production process. These flame retardants interfere with the combustion process through physical or chemical effects.

Flame Retardant Mechanism (Common Method):

Cooling Effect: The flame retardant decomposes, absorbing heat and lowering the temperature of the foam and surrounding materials.

Isolation Effect: It forms an expanded char layer (a “firewall”) that prevents oxygen and heat from entering the interior, protecting the underlying materials.

Dilution Effect: Decomposition produces non-combustible gases (such as water vapor and carbon dioxide), which dilute the concentration of combustible gases and oxygen.

Chain Reaction Interruption: It captures the free radicals that sustain the combustion process, interrupting the combustion chain reaction.

Combustion Behavior: When exposed to an open flame, flame-retardant foams are:

More difficult to ignite.

The flame spread rate is significantly reduced.

They self-extinguish (stop burning) more quickly after being removed from the flame.

The smoke produced during combustion is generally less toxic (but not always, depending on product certification).