Intumescent Coating Fire Protection via Composite Char

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Solution Overview

Problem

There is a need for intumescent coatings that provide improved fire protection by delaying the effects of a fire and slowing the rate of temperature increase on coated substrates.

Innovation Solution

A mixture curable in the presence of a metallic catalyst, comprising a siloxane polymer, a cross-linker, a char reinforcing filler, and an intumescent ingredient with a phosphorus-containing compound and expandable graphite, which expands to form a protective char when exposed to fire.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional intumescent coatings are used, then the coating provides basic fire protection, but the rate of temperature increase of the coated substrate is not sufficiently slowed

Engineering Contradiction:
Improvefire protection effectivenessVSAvoidrate of temperature increase
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent uses a composite intumescent coating system comprising siloxane polymer, cross-linker, char reinforcing filler, and intumescent ingredients including phosphorus-containing compound and expandable graphite. This composite formulation creates a synergistic effect where the expandable graphite provides thermal expansion and insulation, the phosphorus-containing compound promotes char formation, and the siloxane polymer matrix provides structural integrity and adhesion. The combination of these materials significantly enhances the coating's ability to slow temperature increase compared to conventional single-material coatings.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent specifies precise compositional parameters: 5-20% phosphorus-containing compound and 10-40% expandable graphite in the intumescent ingredient. By optimizing these parameter ranges, the coating achieves maximum fire protection effectiveness while minimizing the rate of temperature increase. The specific ratios of these components are critical for achieving the desired thermal performance and char formation characteristics.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the coating expands to form protective char, then fire protection is improved, but the coating material is consumed in the process

Engineering Contradiction:
Improvefire protectionVSAvoidcoating material consumption
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The intumescent coating utilizes phase transition of the expandable graphite, which undergoes endothermic decomposition and expansion when exposed to fire temperatures. This phase transition absorbs significant thermal energy and transforms the coating from a thin protective layer into a thick, insulating char structure. The siloxane polymer also undergoes condensation and charring reactions, contributing to the formation of a stable, expanded protective barrier that consumes heat and slows temperature rise.

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The patent converts the potentially harmful effect of coating material consumption during fire exposure into a beneficial protective mechanism. The controlled decomposition and expansion of the intumescent ingredients (phosphorus-containing compound and expandable graphite) transforms the coating from a passive barrier into an active protective system that expands to insulate the substrate. The char formation, while consuming coating material, creates a thermally insulating layer that protects the underlying substrate from fire damage.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 intumescent coating material effectively expands to form a protective char, providing a physical barrier that insulates the substrate, thereby delaying the effects of a fire and protecting the substrate from failure.

Implementation Method 1

The expandable graphite may have an onset of expansion temperature of 160 to 180° C.

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

a cross-linker for cross-linking the siloxane polymer

Methodology Applied
Scientific EffectCross-linking: Chemical Bonding

Implementation Method 3

the phosphorus containing compound or composition comprising a phosphorus containing compound

Methodology Applied
Scientific EffectThermal decomposition: Pyrolysis

Implementation Method 4

The protective Char acts as a physical barrier insulating the substrate and therefore delaying the effects of a fire and slowing the rate of temperature increase of the coated substrate

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS12297372B2Protective coatings
Publication Date: 2025.05.13 ADVANCED INSULATION LTD

AI summary

A mixture curable in the presence of a suitable metallic catalyst to provide an intumescent coating material. The mixture comprises: a siloxane polymer; a cross-linker for cross-linking the siloxane polymer; filler, wherein the filler comprises char reinforcing filler; and an intumescent ingredient. The intumescent ingredient comprises a phosphorus containing compound or a composition comprising a phosphorus containing compound. The mixture comprises 5 to 20% by weight of the phosphorus containing compound or composition comprising a phosphorus containing compound. The intumescent ingredient comprises 10 to 40% by weight expandable graphite.