Intumescent Coating Reduces Smoke in Hydrocarbon Fires
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Solution Overview
Problem
Existing fire protection coatings for metal, wood, and plastics substrates are inadequate in resisting damage from hydrocarbon fires, particularly in scenarios assessed by the UL1709 test, as they often emit significant smoke and have limited thermal resistance.
Innovation Solution
A fire-resistant intumescent coating composition comprising polydimethylsiloxane with reactive hydroxyl or hydrolysable groups, a crosslinking agent, expandable graphite, and a titanate catalyst, along with mineral fibres and silica or clay, which expands to form a low-smoke insulating char layer when exposed to fire, without using organic polymers or resins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional intumescent coatings containing organic polymers or resins are used, then the coating provides fire protection to substrates, but the coating emits significant smoke and has limited thermal resistance in hydrocarbon fires
Solution Approach 1:
The patent removes organic polymers and resins from the intumescent coating formulation, extracting the harmful components that generate excessive smoke during combustion. The coating is reformulated to use only inorganic binders (silicates, water glass), expandable graphite, and mineral fillers, which do not produce significant smoke when exposed to fire while maintaining or improving thermal resistance properties.
Solution Approach 2:
The patent creates a composite intumescent coating material combining inorganic binders (silicate, water glass), expandable graphite (as intumescent agent), and mineral fillers (alumina, silica, magnesia). This composite formulation achieves both low smoke emission and high thermal resistance by synergistically combining materials with complementary fire-resistant properties, where expandable graphite provides thermal insulation through expansion and inorganic components provide structural stability and smoke-free combustion.
2Temperature
If organic polymer-based intumescent coatings are used, then the coating forms an insulating char layer when exposed to fire, but the char layer produces high smoke opacity
Solution Approach 1:
The patent creates an inert, smoke-free environment within the char layer by using exclusively inorganic materials that do not undergo carbon-based combustion. The silicate-based binder and mineral fillers decompose or melt without producing smoke, while expandable graphite expands to form a physical barrier that isolates the substrate from heat while contributing to a smokeless protective atmosphere during fire exposure.
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 coating significantly enhances the thermal resistance and reduces smoke opacity, providing superior protection against hydrocarbon fires compared to conventional intumescent coatings, while maintaining effectiveness in cellulosic fire scenarios.
Implementation Method 1
a crosslinking agent (B) containing hydrolysable groups reactive with the reactive groups of (A) in the presence of moisture
Implementation Method 2
a titanate catalyst for the reaction between the reactive hydroxyl or hydrolysable groups of polydimethylsiloxane (A) and the crosslinking agent (B)
Implementation Method 3
expandable graphite and a titanate catalyst for the reaction between the reactive hydroxyl or hydrolysable groups of polydimethylsiloxane (A) and the crosslinking agent (B), characterized in that the composition comprises mineral fibres and also comprises at least a silica and/or clay
Implementation Method 4
The coating significantly enhances the thermal resistance and reduces smoke opacity, providing superior protection against hydrocarbon fires
Data Source
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AI summary
A process for protecting a metal, wood or plastics substrate exposed to fire risk from hydrocarbons, comprising coating the substrate with an intumescent composition comprising a polydimethylsiloxane (A) of degree of polymerisation at least 300 siloxane units, said polydimethylsiloxane containing reactive hydroxyl or hydrolysable groups bonded to silicon, and a crosslinking agent (B) containing hydrolysable groups reactive with the reactive groups of (A) in the presence of moisture, expandable graphite and a titanate catalyst for the reaction between the reactive hydroxyl or hydrolysable groups of polydimethylsiloxane (A) and the crosslinking agent (B).