Halogen-Free Epoxy Resin Composition for Low-Temperature Fire Protection

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Solution Overview

Problem

Existing fibre-reinforced resin composite materials face challenges in achieving a balance between fire, smoke, and toxicity (FST) properties, mechanical properties, and processing costs, particularly in aerospace and railway applications, due to the limitations of phenolic and halogenated epoxide resins, which often require high-pressure curing and release volatile compounds.

Innovation Solution

A halogen-free epoxide resin composition incorporating a specific blend of fire retardant additives, including melamine, ammonium polyphosphate, and metal oxoanion salts or glass/ceramic materials, optimized to provide high thermal stability, low viscosity for impregnation, and low steric hindrance, allowing for low-temperature curing and enhanced mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If phenolic resins are used to achieve fire retardant properties, then fire, smoke and toxicity properties are improved, but processing cost increases and health and safety performance deteriorates

Engineering Contradiction:
Improvefire retardant propertiesVSAvoidprocessing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive phenolic resins with a cheaper epoxide resin system that achieves comparable fire retardant properties through the addition of fire retardant additives, thereby reducing processing costs while maintaining reliability

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent creates a composite resin system by combining epoxide resin with fire retardant additives (such as aluminum trihydrate, magnesium hydroxide, or boron nitride) to achieve the fire retardant properties previously only available from phenolic resins, thus avoiding the high costs and health safety issues associated with phenolic materials

Inventive Principle:
Principle #40Composite materials

2Reliability

If halogenated epoxides are used to achieve fire retardant properties, then fire retardancy is improved, but health and safety characteristics deteriorate

Engineering Contradiction:
Improvefire retardancyVSAvoidtoxicity
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes harmful halogenated compounds from the resin system and replaces them with halogen-free epoxide resins combined with safe inorganic fire retardant additives, thereby achieving fire retardancy without the toxic smoke and health hazards associated with halogenated materials

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the traditionally harmful approach of using halogenated fire retardants into a beneficial halogen-free system where inorganic additives like aluminum trihydrate and magnesium hydroxide provide fire retardancy through endothermic decomposition, converting potential harm into a safe and effective fire protection mechanism

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

3Object-affected harmful factors

If addition-cured epoxide resins are used to improve health and safety properties, then health and safety performance is improved, but fire retardant properties deteriorate

Engineering Contradiction:
Improvehealth and safety propertiesVSAvoidfire retardant properties
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent merges the health and safety benefits of addition-cured epoxide resins with the fire retardant properties of inorganic additives, creating a hybrid system that achieves both improved health and safety performance and adequate fire retardancy, thereby resolving the contradiction between these two requirements

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If phenolic resins are used to achieve fire retardant properties, then fire, smoke and toxicity properties are improved, but mechanical properties deteriorate

Engineering Contradiction:
Improvefire, smoke and toxicity propertiesVSAvoidmechanical properties
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent replaces phenolic resins with epoxide resin systems that inherently provide superior mechanical properties, while achieving fire retardancy through additive incorporation, thus improving both mechanical performance and fire safety simultaneously

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 resin composition achieves superior FST properties while maintaining mechanical integrity and reducing processing costs, eliminating volatile emissions, and improving surface finish quality, making it suitable for aerospace and railway interior components.

Implementation Method 1

a non-halogenated epoxide-containing resin which has been chemically modified with a phosphorous-containing molecule

Methodology Applied
Scientific EffectThermal decomposition: Pyrolysis

Implementation Method 2

the cured resin exhibits fire retardant properties

Methodology Applied
Scientific EffectChar formation: Intumescent Materials

Implementation Method 3

a non-halogenated epoxide-containing resin which has been chemically modified with a phosphorous-containing molecule

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 4

the cured resin exhibits fire retardant properties and enhanced mechanical performance

Methodology Applied
Scientific EffectCross-linking:

Implementation Method 5

along with a tailored catalyst system, to enhance fire retardancy and mechanical properties while allowing low-temperature curing

Methodology Applied
Scientific EffectCatalysis: Catalysis

Data Source

PatentEP3807352B1Fire-retardant resins and composite materials
Publication Date: 2026.04.22 GURIT (UK) LTD
  • EP3807352B1 patent drawingFigure 1~2
  • EP3807352B1 patent drawingFigure 3

AI summary

An epoxide resin for the manufacture of a fibre-reinforced composite material having fire retardant properties and/or for use as an adhesive or hot-melt adhesive having fire retardant properties, the epoxide resin being halogen-free and phenolic resin-free, the epoxide resin comprising: A. a mixture of (i) at least one first non-halogenated multifunctional epoxide-containing resin which has an epoxide functionality of greater than 2 and (ii) at least one second non-halogenated multifunctional epoxide-containing resin which has an epoxide functionality of less than or equal to 2; B. at least one catalyst for curing the mixture of epoxide-containing resins to form a cured epoxy resin; and C. a mixture of first, second and third fire retardant additives for reacting together to form an intumescent char when the cured epoxy resin is exposed to a fire, wherein (i) the first fire retardant additive comprises a blowing agent for generating a non-combustible gas, (ii) the second fire retardant additive comprises an acid donor for decomposing to form a phosphoric acid when the cured epoxy resin is exposed to a fire, and (iii) the third fire retardant additive comprises at least one or both of (a) a ceramic or glass material and (b) a ceramic or glass material precursor to form a ceramic or glass material when the cured epoxy resin is exposed to a fire.