Intumescent Coating Char Expansion for Fire-Resistant Panels
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Solution Overview
Problem
Existing fire-resistant substrates, such as oriented strand board and plywood, are inherently flammable and do not meet standardized fire-resistant tests like ASTM E2768-11(2018) and ASTM E119-07(2021), necessitating the development of improved fire-resistant overlays and panels.
Innovation Solution
A fire-resistant overlay comprising a fiber mat with a coating of a blowing agent and a partially cured intumescent resin, applied on one or both sides, which satisfies modified flame resistance tests by producing a char with specific density, length, height, and expansion ratio when subjected to a modified ASTM D6413-99 test.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If intumescent coatings are applied to substrate surfaces to reduce flammability, then the flammability of substrates is reduced, but the coatings still fail to satisfy certain standardized fire-resistant tests such as ASTM E2768-11(2018) and ASTM E119-07(2021)
Solution Approach 1:
The patent applies composite materials by combining a fiber mat (cellulose or synthetic fibers) with intumescent coating layers containing blowing agents and resins. This composite structure creates a multi-layer fire-resistant overlay that achieves the required fire performance ratings (ASTM E2768-11 and ASTM E119-07) by integrating different material properties: the fiber mat provides structural base while the intumescent layers provide fire protection through char formation and expansion.
Solution Approach 2:
The patent employs parameter changes by modifying the intumescent coating formulation to include specific blowing agents (ammonium polyphosphate, melamine cyanurate) and resins (polyvinyl acetate, polyacrylic acid) in controlled ratios. The coating is applied at specific thicknesses (0.5-2.0 mm) and cured to achieve partial cross-linking, which optimizes the char formation properties and expansion ratio to meet fire-resistant test requirements.
2Adaptability or versatility
If existing substrates like oriented strand board and plywood are used in building construction, then construction applications are enabled, but the substrates are inherently flammable which limits their applications
Solution Approach 1:
The patent applies preliminary action by pre-applying the fire-resistant overlay to substrates before installation in building construction. The overlay is manufactured with pre-cured intumescent resin and blowing agent layers that are already optimized for fire protection, allowing substrates to be fire-retardant ready before they reach the construction site, thus enabling safe construction applications without requiring post-installation fire treatment.
Solution Approach 2:
The fire-resistant overlay acts as an intermediary layer between the flammable substrate and the fire environment. This intermediate protective layer includes a fiber mat bonded to the substrate with adhesive, covered by intumescent coating layers that form a protective char barrier during fire exposure, thereby mediating the interaction between the substrate and fire while maintaining structural integrity.
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 solution effectively enhances the fire-resistant properties of substrates, enabling them to pass extended duration surface burning characteristics and fire tests, as per ASTM E2768-11(2018) and ASTM E119-20 standards, by forming an expanded non-flammable char that shields the substrate from heat and oxygen.
Implementation Method 1
The coating can include a blowing agent and an at least partially cured intumescent resin. When a side of the fiber mat that includes the coating disposed thereon is subjected to a modified standard test method for flame resistance of textiles, ASTM D6413-99, where the test is modified by using a run time of 5 minutes instead of 12 seconds, a char can be produced. The char can have a density of about 0.05 g/cm3 to about 0.2 g/cm3, a length of about 8.8 cm to about 10.2 cm, a height of about 1.25 cm to about 2.5 cm, and an expansion ratio of about 10 to about 17.5.
Implementation Method 2
The intumescent coatings act by forming an expanded layer of non-flammable or hardly flammable material when exposed to sufficient heat that shields the substrate from oxygen and/or from overheating to prevent or at least slow the spread of flame and to prevent or at least delay reductions in mechanical properties of the substrates.
Implementation Method 3
The coating can include a blowing agent and an at least partially cured intumescent resin. The char can have a density of about 0.05 g/cm3 to about 0.2 g/cm3 and an expansion ratio of about 10 to about 17.5.
Data Source
AI summary
Fire-resistant overlays, panels, and processes for making and using same. The fire-resistant overlay can include a fiber mat that can include a plurality of fibers secured to one another. The fire-resistant overlay can include a coating disposed on at least one of a first and a second side thereof. The coating can include a blowing agent and an at least partially cured intumescent resin. When a side of the fiber mat that includes the coating disposed thereon is subjected to a modified ASTM D6413-99 test, where the test is modified by using a run time of 5 minutes instead of 12 seconds, a char can be produced. The char can have a density of about 0.05 g/cm3 to about 0.2 g/cm3, a length of about 8.8 cm to about 10.2, a height of about 1.25 cm to about 2.5 cm, and an expansion ratio of about 10 to about 17.5.