Porous Material Process Using Polymeric Isocyanates
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Solution Overview
Problem
Existing porous materials based on polyurea have unsatisfactory mechanical stability and thermal conductivity, with high water uptake increasing thermal conductivity and reducing insulating properties, and mixing defects leading to heterogeneous materials.
Innovation Solution
A process involving a mixture of polymeric and monomeric polyfunctional isocyanates with an isocyanate trimerization catalyst, substantially free of aromatic amines, to form aerogels or xerogels with reduced shrinkage and density, achieving improved thermal conductivity and mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If porous materials are produced using known polyurea-based processes, then thermal insulation is achieved, but mechanical stability and compressive strength are insufficient
Solution Approach 1:
The patent changes the chemical composition parameters by using polymeric isocyanates with specific functionality (2.5-4.0) and controlling the NCO-OH ratio (0.8-1.2), along with specific catalyst systems and processing conditions, to achieve both low thermal conductivity and high mechanical stability simultaneously
Solution Approach 2:
The patent creates composite porous materials combining polymeric isocyanates with specific polyols or aromatic amines, forming a composite network structure that provides both excellent thermal insulation properties and enhanced mechanical strength through the synergistic interaction of components
2Stability of the object's composition
If aromatic amines are used in the composition, then gel formation occurs, but mixing defects and heterogeneous material properties result
Solution Approach 1:
The patent modifies the composition by substantially eliminating aromatic amines and using alternative compounds, while adjusting the NCO-OH ratio and using specific catalyst systems to achieve homogeneous gel formation without mixing defects
Solution Approach 2:
The patent employs preliminary mixing of isocyanate and catalyst components before adding the reactive component, ensuring uniform distribution and preventing localized hot spots that cause heterogeneity, while maintaining controlled gel formation
3Loss of energy
If high porosity is achieved in porous materials, then thermal insulation improves, but mechanical stability decreases
Solution Approach 1:
The patent optimizes the porosity parameter to a specific range (70-90%) rather than maximizing it, while simultaneously adjusting the polymeric isocyanate functionality, crosslinking density, and curing conditions to maintain mechanical stability at these high porosity levels
Solution Approach 2:
The patent employs controlled porous structure formation through specific gelation and drying processes, creating a uniform pore distribution that provides excellent thermal insulation while the pore walls maintain sufficient thickness and strength for mechanical stability
4Strength
If polymeric isocyanates with high functionality are used, then crosslinking density increases improving mechanical strength, but thermal conductivity increases reducing insulation
Solution Approach 1:
The patent selects polymeric isocyanates with functionality in the optimal range of 2.5-4.0, avoiding both low functionality (insufficient strength) and excessively high functionality (increased thermal conductivity), while adjusting crosslinking density and pore structure to balance these properties
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 process results in porous materials with low thermal conductivity, high porosity, and mechanical stability, suitable for thermal insulation, particularly in the ventilated state, with reduced shrinkage and density, enhancing their insulating properties.
Implementation Method 1
isocyanate composition (A*) comprising a polymeric polyfunctional isocyanate as component (ai), a monomeric polyfunctional isocyanate as component (aii), and at least one catalyst as component (ac)
Implementation Method 2
at least one catalyst as component (ac), wherein composition (A) is substantially free of aromatic amines, reacting the components in the composition (A) obtaining an organic gel
Implementation Method 3
drying of the gel obtained in step b), wherein composition (A) is substantially free of aromatic amines, reacting the components in the composition (A) obtaining an organic gel
Data Source
AI summary
The present invention relates to a process for preparing a porous material, at least comprising the steps of providing a mixture (I) comprising a composition (A) at least comprising an isocyanate composition (A*) comprising a polymeric polyfunctional isocyanate as component (ai), a monomeric polyfunctional isocyanate as component (aii), at least one catalyst as component (ac),wherein composition (A) is substantially free of aromatic amines,and a solvent (B),reacting the components in the composition (A) obtaining an organic gel, and drying of the gel obtained in step b). The invention further relates to the porous materials which can be obtained in this way and the use of the porous materials as thermal insulation material and in vacuum insulation panels.