THPS-Based Flame Retardant Composition to Reduce Formaldehyde Content

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Solution Overview

Problem

Existing flame-retardant precursors for textiles contain high levels of formaldehyde, making them hazardous during storage, transportation, and handling, and difficult to manage within regulatory limits.

Innovation Solution

Using tetrakis(hydroxyorgano) phosphonium sulfate (THPS) instead of tetrakis(hydroxyorgano) phosphonium chloride (THPC) to form a condensate with urea or thiourea, reacting at temperatures below 100°C to achieve a formaldehyde content of less than 0.1% and reducing odour during application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If THPC is used to form flame-retardant condensate, then flame-retardant properties are achieved, but formaldehyde content becomes high causing toxicity and handling issues

Engineering Contradiction:
Improveflame-retardant propertiesVSAvoidformaldehyde content
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the counterion parameter of the phosphonium salt from chloride (THPC) to sulfate (THPS). This parameter change fundamentally alters the formaldehyde release behavior during condensation reactions, reducing formaldehyde content in the final flame-retardant composition while preserving the essential flame-retardant properties of the phosphonium-based system.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If reaction temperature is increased to improve reaction efficiency, then manufacturing speed increases, but formaldehyde content increases making the product hazardous

Engineering Contradiction:
Improvereaction efficiencyVSAvoidformaldehyde content
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent demonstrates that using THPS instead of THPC changes the temperature-formaldehyde relationship. The sulfate-based system allows for effective condensation reactions at lower temperatures without generating excessive formaldehyde, thereby decoupling the trade-off between reaction efficiency and formaldehyde content that exists with chloride-based systems.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If formaldehyde content is reduced to meet regulations, then safety and compliance improve, but flame-retardant effectiveness may be compromised

Engineering Contradiction:
Improveformaldehyde contentVSAvoidflame-retardant effectiveness
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent shows that changing the counterion from chloride to sulfate in the phosphonium salt enables the system to achieve both low formaldehyde content and effective flame-retardant performance. The sulfate anion appears to stabilize the condensation products or alter the reaction pathway, allowing flame-retardant condensates to form with minimal formaldehyde release.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite chemical system combining the phosphonium cation with the sulfate anion (THPS), which exhibits synergistic properties. This composite approach allows the system to simultaneously achieve low formaldehyde content and high flame-retardant effectiveness, as the sulfate component contributes to both reduced formaldehyde release and maintained flame-retardant functionality.

Inventive Principle:
Principle #40Composite 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 THPS-based condensate significantly reduces formaldehyde content and odour, enhancing safety and compliance with regulations while maintaining effective flame-retardant properties.

Implementation Method 1

reaction of: (a) a tetrakis (hydroxyorgano) phosphonium sulfate (herein "THPS"); (b) urea or thiourea (herein "(thio)urea")

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

comprise a precursor that reacts under ammonia curing to form a polymer, said polymer imparting the sought flame retardant properties

Methodology Applied
Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentEP3387182B1Flame retardant compositions with low formaldehyde content
Publication Date: 2025.01.08 ENERGY SOLUTIONS US LLC

AI summary

The instant invention relates to a composition useful as a precursor for imparting flame-retardant properties to textile articles, comprising a condensate of : (a) a tetrakis (hydroxyorgano) phosphonium sulfate THPS; (b) urea, or alternatively thiourea; (c) optionally, and preferably, an aliphatic hydroxyl-reactive compound, such an amine wherein said composition has a very low free formaldehyde content, namely of less than 0,1 %.