Polyisocyanurate Foam Boards with Non-Halogenated Fire Retardant
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Solution Overview
Problem
Existing polyisocyanurate foam insulation boards require halogenated fire retardants to pass fire tests like ASTM E-84, which some specifiers wish to avoid due to environmental concerns, and conventional non-halogenated alternatives struggle to match their fire-resistant performance.
Innovation Solution
Incorporating a phosphorus-containing non-halogenated fire retardant, such as diethyl hydroxymethyl phosphonate (DEHMP), into the polyisocyanurate foam formulation to enhance char formation and stability, allowing the foam to pass ASTM E-84 and E1354 tests without halogenated compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If halogenated fire retardants (such as TCPP) are used in polyisocyanurate foam, then fire resistance performance is improved and ASTM E-84 test is passed, but environmental harm increases and specifiers avoid using such materials
Solution Approach 1:
The patent changes the chemical composition parameters by substituting halogenated fire retardants with non-halogenated alternatives, specifically using phosphorus-containing compounds and metal hydroxides in optimized concentrations to maintain fire resistance while eliminating environmental harm
Solution Approach 2:
The patent employs composite fire retardant systems combining multiple non-halogenated additives (phosphorus compounds, metal hydroxides, nitrogen-containing compounds) working synergistically to achieve fire resistance performance comparable to or exceeding halogenated systems without the associated environmental drawbacks
2Object-affected harmful factors
If non-halogenated fire retardants are used in polyisocyanurate foam, then environmental harm is reduced, but fire resistance performance deteriorates and ASTM E-84 test cannot be passed
Solution Approach 1:
The patent optimizes the concentration and selection of non-halogenated fire retardant components, using phosphorus-containing compounds at 1-10 wt%, metal hydroxides at 5-20 wt%, and nitrogen-containing compounds at 1-5 wt% to achieve sufficient fire resistance without halogenated compounds
Solution Approach 2:
The patent introduces synergistic combinations of fire retardant additives where phosphorus compounds form protective char layers, metal hydroxides release water vapor to suppress flames, and nitrogen-containing compounds contribute to flame inhibition, creating a multi-mechanism fire protection system
3Object-affected harmful factors
If conventional non-halogenated fire retardants are used, then halogenated materials are eliminated, but fire test performance (ASTM E-84 and E1354) is insufficient
Solution Approach 1:
The patent develops a composite fire retardant system integrating phosphorus-containing compounds for char formation, metal hydroxides for endothermic decomposition and water vapor release, and nitrogen-containing compounds for flame suppression, achieving synergistic effects that satisfy both ASTM E-84 and E1354 test requirements
Solution Approach 2:
The patent enhances local fire resistance properties by distributing fire retardant additives uniformly throughout the polyisocyanurate foam matrix and concentrating protective mechanisms at critical interfaces where flame propagation would occur
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The use of DEHMP enables polyisocyanurate foam boards to achieve similar or better fire-resistant performance compared to halogenated fire retardant systems, while eliminating the need for halogenated materials, thus providing effective thermal insulation and fire safety without environmental drawbacks.
Implementation Method 1
Incorporating a phosphorus-containing non-halogenated fire retardant, such as diethyl hydroxymethyl phosphonate (DEHMP), into the polyisocyanurate foam formulation to enhance char formation and stability
Data Source
AI summary
According to one embodiment, a halogen free roof system is described. The roof system includes a structural deck that is positioned above joists or other support members. Polyisocyanurate foam insulation is positioned atop the structural deck. The polyisocyanurate foam insulation has an isocyanate index greater than 200 and includes a polyisocyanurate core having a halogen free fire retardant. A water proof membrane is positioned atop the polyisocyanurate foam insulation. The polyisocyanurate core is able to form a sufficiently stable char when exposed to flame conditions such that the polyisocyanurate core is able to pass the ASTM E-84 test.