Low-Monomer PU Foam Composition via Polyol Molecular Weight Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional single-component polyurethane (PU) foams have high monomeric diisocyanate content, leading to volatile emissions and health hazards during processing, and when reduced, they exhibit high viscosity and lack initial strength, making them difficult to use effectively in construction and DIY applications without solvents or plasticizers.
Innovation Solution
A crosslinkable foam composition with a low content of monomeric isocyanates, comprising 70-99.8% prepolymers made from polyether polyols reacted with aromatic diisocyanates, and containing additives and blowing agents, which maintains low viscosity and high initial strength, allowing for safe and effective use as foam materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the content of monomeric diisocyanates is reduced to improve health safety and reduce emissions, then the viscosity of the foam increases and initial strength decreases
Solution Approach 1:
The patent changes the molecular weight parameter of the polyol component, using high molecular weight polyols (MN > 3000 g/mol) instead of conventional low molecular weight polyols. This parameter change allows the formulation to achieve both low monomer content (<2%) and adequate initial strength, as the high molecular weight polyol provides sufficient viscosity and structural integrity without requiring high monomer content.
2Object-affected harmful factors
If the content of monomeric diisocyanates is reduced to improve health safety, then the viscosity of the foam increases making it difficult to process
Solution Approach 1:
The patent changes the molecular weight parameter of the polyol component, using high molecular weight polyols (MN > 3000 g/mol) instead of conventional low molecular weight polyols. This parameter change allows the formulation to achieve both low monomer content (<2%) and adequate initial strength, as the high molecular weight polyol provides sufficient viscosity and structural integrity without requiring high monomer content.
3Object-affected harmful factors
If conventional low-monomer PU prepolymers are used, then health safety improves, but the viscosity becomes too high requiring solvents or plasticizers
Solution Approach 1:
The patent changes the molecular weight parameter of the polyol component, using high molecular weight polyols (MN > 3000 g/mol) instead of conventional low molecular weight polyols. This parameter change allows the formulation to achieve both low monomer content (<2%) and adequate initial strength, as the high molecular weight polyol provides sufficient viscosity and structural integrity without requiring high monomer content.
Solution Approach 2:
The patent eliminates the need for solvents and plasticizers by using high molecular weight polyols, which inherently provide the necessary viscosity and performance characteristics. This approach removes harmful additives from the formulation, simplifying the system and improving environmental and health safety.
4Object-affected harmful factors
If high molecular weight polyols are used to reduce monomer content, then health safety improves, but the viscosity increases making the foam unprocessable
Solution Approach 1:
The patent changes the molecular weight parameter of the polyol component, using high molecular weight polyols (MN > 3000 g/mol) instead of conventional low molecular weight polyols. This parameter change allows the formulation to achieve both low monomer content (<2%) and adequate initial strength, as the high molecular weight polyol provides sufficient viscosity and structural integrity without requiring high monomer content.
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 composition achieves a balance of low viscosity for foamability and high initial strength, reducing health risks and improving mechanical properties of the cross-linked foam, while meeting occupational safety standards.
Implementation Method 1
The one-component PUR foam becomes solid through the crosslinking reactions with moisture.
Implementation Method 2
at least one blowing agent, the polyols having a functionality of less than 2.5
Data Source
AI summary
The invention relates to a foamable composition that can be cross-linked, having a low monomeric isocyanate content, comprising 70 to 99.8 wt % of prepolymers produced from polyester polyols and/or polyether polyols by reacting same with an excess of aromatic diisocyanates and subsequently removing excess monomeric diisocyanate, 0.2 to 30 wt % of additives and at least one propellant, wherein the polyols comprise a functionality of less than 2.5, the polyols have a molar mass (MN) between 150 and 3000 g/mol, and the prepolymers comprise a monomeric diisocyanate content of less than 5 wt %.