Reactive Flame Retardant Blends for Flexible Polyurethane Foams
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Solution Overview
Problem
Flexible polyurethane foams face challenges with inconsistent air permeation and scorching due to high exothermic reactions during manufacturing, which can lead to flammability issues and waste, especially in low-density foams without auxiliary blowing agents, and existing reactive flame retardants fail to maintain uniformity and prevent discoloration.
Innovation Solution
A novel reactive flame retardant blend comprising a brominated aromatic diester diol and an epoxy resin, optionally with a hindered phenolic antioxidant, is developed to enhance flame retardancy, air permeation uniformity, and scorch prevention in combustion modified flexible polyurethane foams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reactive flame retardant compounds are incorporated into flexible polyurethane foam to reduce VOC emissions and improve fire retardancy, then flame retardancy is improved, but air permeation uniformity deteriorates
Solution Approach 1:
The patent modifies the chemical parameters of the flame retardant system by using a blend of reactive flame retardant compounds with specific functional groups that react differently with isocyanates. This parameter change in chemical reactivity and molecular structure allows the system to maintain both fire retardancy and air permeation uniformity, resolving the contradiction between these two properties.
Solution Approach 2:
The patent creates a composite flame retardant system by blending multiple reactive flame retardant compounds together. This composite approach allows the different components to compensate for each other's deficiencies, with some components maintaining air permeation while others provide fire retardancy, thus resolving the contradiction between these two properties.
2Quantity of substance
If high concentration of water is used to lower foam density, then foam density is reduced, but exothermic reaction increases causing scorching
Solution Approach 1:
The patent introduces auxiliary blowing agents as intermediary substances that facilitate foam expansion and density reduction without requiring high concentrations of water. These intermediary agents perform the blowing function while generating less exothermic heat, thus resolving the contradiction between achieving low density and controlling reaction temperature.
Solution Approach 2:
The patent changes the chemical composition parameters of the blowing system by substituting water with auxiliary blowing agents having different reaction characteristics. This parameter change in the blowing mechanism reduces the exothermic intensity while maintaining the desired density, resolving the temperature-density contradiction.
3Quantity of substance
If auxiliary blowing agents are used to reduce exotherm and achieve low density, then foam density is improved, but environmental harm increases
Solution Approach 1:
The patent changes the environmental safety parameters of the blowing system by selecting auxiliary blowing agents with favorable environmental profiles. This parameter change in environmental compatibility allows the use of blowing agents that achieve low density while minimizing environmental harm, resolving the contradiction between density performance and environmental impact.
4Duration of action of stationary object
If high temperatures are maintained in foam billet center for extended period, then polymerization is completed, but scorching and discoloration occur
Solution Approach 1:
The patent introduces reactive flame retardant compounds as intermediary substances that actively participate in the polymerization process and modify the thermal behavior of the foam matrix. These intermediary compounds help dissipate or manage the heat generated during curing, preventing excessive temperature accumulation that causes scorching, thus resolving the contradiction between complete curing and scorch prevention.
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 blend achieves uniform air permeation and minimizes scorching while providing effective flame retardancy, ensuring consistent foam quality and reducing waste by stabilizing the foam matrix against thermal degradation.
Implementation Method 1
Polyurethane foam is formed by a reaction between a polyol and diisocyanate. This reaction is highly exothermic.
Implementation Method 2
The heat of reaction can degrade residual chemicals within the polymer matrix to form color bodies. Some of those residual chemicals, such as halogenated flame retardants produce halogenated acids that breakdown the urethane linkages
Implementation Method 3
Polyurethane foam is formed by a reaction between a polyol and diisocyanate
Data Source
AI summary
A flexible polyurethane foam containing a flame retardant blend of at least one diester diol a ring-brominated aromatic compound and at least one epoxy resin.