Flame-Proof Polyurethane Foam Using Graphite and Organophosphorus

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Solution Overview

Problem

Low-density polyurethane foams face challenges with effective flame protection due to high susceptibility to fire, odor emissions, and negative influences on mechanical properties and foaming reactions from traditional flame retardants, particularly at densities of 50 g/L and less.

Innovation Solution

A process involving a reaction mixture of organic polyisocyanate, polymeric compounds with isocyanate-reactive hydrogen atoms, chain extenders, expandable graphite, and oligomeric organophosphorus flame retardants is used to produce semi-rigid or rigid polyurethane foams with improved flame retardancy, mechanical properties, and reduced emissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If halogenated flame retardants are used to improve fire protection, then flame retardancy is enhanced, but toxicological and ecological harm increases along with smoke gas density

Engineering Contradiction:
Improveflame retardancyVSAvoidtoxicological and ecological harm
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of flame retardants by using expandable graphite combined with organophosphorus compounds instead of halogenated compounds. This substitution maintains flame retardancy while eliminating the toxicological and ecological harm associated with halogenated substances.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite flame retardant system combining expandable graphite with organophosphorus flame retardants. This composite approach achieves effective fire protection without the harmful effects of halogenated compounds, resolving the contradiction between reliability and harmful factors.

Inventive Principle:
Principle #40Composite materials

2Reliability

If common phosphorus-containing flame retardants are used to improve flame protection, then fire safety is enhanced, but odor emissions increase and mechanical properties deteriorate

Engineering Contradiction:
Improvefire safetyVSAvoidodor emissions
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent modifies the parameters of phosphorus-containing flame retardants by selecting specific organophosphorus compounds and controlling their concentration. This approach achieves fire safety while minimizing odor emissions and maintaining mechanical properties through optimized formulation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies flame retardant components selectively, using expandable graphite as a primary component that provides fire protection without odor emissions. The organophosphorus compounds are used in controlled amounts to enhance flame retardancy while minimizing negative effects on mechanical properties and emissions.

Inventive Principle:
Principle #3Local quality

3Reliability

If traditional flame retardants are used to improve fire protection, then flame retardancy is enhanced, but foaming reaction is negatively influenced and mechanical properties deteriorate

Engineering Contradiction:
Improveflame retardancyVSAvoidfoaming reaction quality
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent optimizes the parameters of the flame retardant system by using expandable graphite combined with specific organophosphorus compounds. This formulation maintains flame retardancy while minimizing interference with the foaming reaction and preserving mechanical properties through careful selection and dosing of components.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses expandable graphite as an intermediary substance that provides flame retardancy without significantly interfering with the foaming reaction. The organophosphorus compounds act as complementary agents that enhance fire protection while maintaining compatibility with the foam structure and mechanical properties.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 foams exhibit excellent fire behavior, minimal shrinkage, and low odor emissions, making them suitable for applications like vehicle sound insulation with enhanced mechanical stability and reduced hydrogen halide release during thermoplastic processing.

Implementation Method 1

the flame retardant containing d) expandable graphite

Methodology Applied
Scientific EffectExpandable graphite expansion: Thermal Expansion

Implementation Method 2

oligomeric organophosphorus flame retardant

Methodology Applied
Scientific EffectFlame inhibition: Chemical Bonding

Data Source

PatentEP2800770B2Flame-proof polyurethane foams
Publication Date: 2020.02.19 BASF SE

AI summary

The invention relates to the production of a flame-protected polyurethane foam having a density of 5 to 50 g/L, in which (a) organic polyisocyanate is mixed with (b) polymeric compounds having at least two isocyanate-reactive hydrogen atoms, optionally (c) chain-extending and/or crosslinking agents, (d) flame retardant, (e) propellant, (f) catalysts, and optionally (g) auxiliary agents and additives to form a reaction mixture and said reaction mixture is left to react, wherein the flame retardant contains (d) expanded graphite and oligomeric organophosphorus flame retardant. The invention further relates to a flame-protected polyurethane foam that can be produced by a method according to the invention and to the use of same in vehicles for sound insulation.