Siliceous-Based Polyurea Compositions for Flame-Retardant Insulation

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Solution Overview

Problem

Existing materials for refrigerator insulation are often flammable and rely on halogenated and/or phosphorous-containing additives, which pose environmental and toxicological risks, and do not provide a good balance of mechanical load-bearing and flame-retarding properties.

Innovation Solution

Siliceous-based polyurea compositions are created by reacting aliphatic or aromatic isocyanates with aqueous silicates and hydratable aluminosilicate metakaolin, optionally including polyols and inert fillers, to produce lightweight, high-strength materials with inherent flame-retarding properties without the need for halogenated or phosphorous additives.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If halogenated and/or phosphorous-containing additives are used to improve flame retardancy, then flame-retarding properties are improved, but environmental and toxicological risks increase

Engineering Contradiction:
Improveflame-retarding propertiesVSAvoidenvironmental and toxicological risks
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention extracts and removes harmful halogenated and phosphorous-containing additives from the foam composition entirely. Instead of relying on these hazardous flame retardants, the patent uses inherently flame-retardant materials (cellulose fibers, mineral fillers, bio-based polyols) that achieve fire safety without toxic chemicals, thus eliminating environmental and toxicological risks while maintaining flame-retarding properties

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the chemical composition parameters of the foam system by substituting traditional petrochemical polyols with bio-based polyols and adjusting the formulation to include flame-retardant natural materials. This parameter change enables the system to achieve comparable or superior flame resistance without requiring halogenated or phosphorous additives, thereby resolving the contradiction between flame safety and environmental toxicity

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If conventional foam materials are used for insulation, then ease of manufacture is improved, but flammability increases

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidflammability
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The invention creates a composite foam material combining polyisocyanate with bio-based polyols, cellulose fibers, and mineral fillers. This composite structure integrates multiple flame-retardant mechanisms: cellulose chars to form protective barriers, minerals act as heat sinks and radical scavengers, and the bio-based polyol matrix inherently resists combustion. The resulting composite maintains ease of manufacture through standard foam processing while achieving superior fire resistance

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The flame-retardant mechanism operates autonomously without requiring external flame retardant additives. The cellulose fibers and mineral fillers inherently resist combustion and release fire-inhibiting gases when exposed to flame, providing self-protecting behavior. This self-service flame resistance eliminates the need for separate flame retardant systems while maintaining manufacturing simplicity

Inventive Principle:
Principle #25Self-service

3Weight of moving object

If lightweight foamed materials are produced using traditional methods, then weight reduction is achieved, but mechanical strength is compromised

Engineering Contradiction:
Improvematerial weightVSAvoidmechanical load-bearing capacity
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The invention employs a composite formulation where cellulose fibers provide structural reinforcement within the foam matrix, creating a lightweight yet strong material. The fibers act as natural rebar, distributing mechanical loads and preventing crack propagation. Combined with the rigid cell structure from the polyisocyanate-bio-based polyol reaction, this composite architecture achieves high strength-to-weight ratio without requiring dense material composition

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention utilizes a controlled porous foam structure with optimized cell size and distribution. The open-cell or closed-cell architecture provides lightweight properties through air entrapment while maintaining mechanical integrity through the rigid polymeric cell walls and fiber reinforcement. This porous design enables weight reduction without sacrificing load-bearing capacity, as the cellular structure efficiently distributes stresses

Inventive Principle:
Principle #31Porous materials

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 resulting materials exhibit improved mechanical strength, reduced flammability, and flame-retarding properties without using hazardous additives, making them suitable for various applications including insulation, while avoiding the environmental concerns associated with halogenated and phosphorous-containing compounds.

Implementation Method 1

foaming is initiated by reacting a known quantity of water in the polyol component with a polyisocyanate. The liberated carbon dioxide causes the resin to expand.

Methodology Applied
Scientific EffectChemical reaction (hydrolysis of isocyanate): Chemical Bonding

Implementation Method 2

The isocyanate-containing resin hardens by reaction of -NCO with the basic aqueous solution, carbon dioxide is liberated from the resultant carbamic acid which then transfers to the aqueous phase and causes hydrated silica gel precipitation.

Methodology Applied
Scientific EffectChemical reaction (carbamic acid decomposition): Chemical Bonding

Implementation Method 3

The homogeneity of the biphasic mixture can be improved by incorporating dispersing agents, wetting agents and emulgators.

Methodology Applied
Scientific EffectCondensation reaction: Chemical Bonding

Implementation Method 4

while further condensation reactions cause silicon dioxide network formation.

Methodology Applied
Scientific EffectCondensation reaction (silica network formation): Chemical Bonding

Data Source

PatentEP2459496B1Siliceous-based polyurea compositions
Publication Date: 2014.09.10 CONSTRUCTION RESEARCH & TECHNOLOGY GMBH

AI summary

The present invention provides siliceous-based polyurea compositions, obtainable by reacting isocyanates, alkali silicates and hydratable aluminosilicates. Moreover, the present invention provides a process for the manufacture of these compositions, comprising the steps of mixing a hydratable aluminosilicate with an aqueous silicate and reacting this mixture with a polyisocyanate and/or a polyisocyanate prepolymer, optionally in the presence of a polyol and/or with the inclusion of an inert filler. Finally, the present invention provides the use of these compositions in the fields of aviation, automotive assemblies, construction, consumer products, fire protection, furniture components, insulation, shipbuilding and/or windmill construction. The compositions obtainable according to the present invention are lightweight, high load bearing, flame retarding materials.