One-Component Polyurethane Gasket Froth Curing
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Solution Overview
Problem
Conventional methods for forming polyurethane gaskets, such as those using high humidity boxes, are energy-intensive and environmentally impactful, and face challenges with stoichiometric control and equipment cleaning in two-component systems, as well as reliance on high humidity for one-component systems.
Innovation Solution
A method involving the frothing of a one-component polyurethane precursor, which is cured in ambient conditions with externally applied water, allowing for a gasket with a density of not greater than 350 kg/m³ and open or closed cell configuration, without the need for artificially raised humidity or temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high humidity boxes are used to facilitate curing of one component polyurethane foams, then the curing process can be achieved, but the energy consumption increases significantly and environmental impact worsens
Solution Approach 1:
The patent changes the humidity parameter from high (60% or more) to ambient levels, and introduces an alternative curing mechanism that does not rely on high humidity. The polyol component is modified to enable curing through a different chemical pathway that works under normal environmental conditions, thereby eliminating the need for energy-intensive humidity control systems.
Solution Approach 2:
The invention extracts the dependency on high humidity from the curing process by using a moisture-cured polyol component that can cure at ambient humidity levels. This removes the requirement for high humidity boxes and their associated energy consumption and environmental impact.
2Reliability
If high humidity boxes are used to maintain high temperature and humidity, then curing is facilitated, but the equipment investment cost and space occupation increase
Solution Approach 1:
The patent removes the dependency on complex high humidity box equipment by using a polyol component formulated to cure at ambient conditions. This eliminates the need for investing in and occupying space with specialized curing equipment, while still achieving reliable curing through the modified chemical composition.
Solution Approach 2:
The polyol component is designed to self-cure at ambient humidity levels without requiring external humidity control systems. The formulation includes moisture-reactive groups that enable the material to cure using the natural moisture present in the environment, making the process self-sufficient and eliminating complex equipment requirements.
3Reliability
If two component systems are used for polyurethane formation, then polyurethane can be formed, but strict control of stoichiometric mixing and equipment cleaning become difficult
Solution Approach 1:
The patent merges the isocyanate component into the polyol component during pre-polymerization, creating a single-component system that contains both reactive groups. This eliminates the need for separate storage and mixing of two components, thereby removing the complexity of stoichiometric control and equipment cleaning while still enabling polyurethane formation through reaction with ambient moisture.
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
This approach reduces energy consumption, minimizes environmental impact, and provides a gasket with desirable mechanical properties and low cure times, while simplifying the manufacturing process by eliminating the need for high humidity boxes.
Implementation Method 1
In the presence of water, a portion of the isocyanate groups are converted into amine groups, which will react with the remaining isocyanate groups resulting in a chemically crosslinked polyurethane network. The carbon dioxide released during this process may help the foaming process.
Implementation Method 2
a gasket with a density of not greater than 350 kg/m³ and open or closed cell configuration
Data Source
Figure 1~2
Figure 3~7
AI summary
A method of forming a seal includes preparing a froth from a one component polyurethane precursor, applying the froth to a surface of an article, and simultaneously applying water with the froth, the froth curing to form a gasket having a density not greater than 350 kg/m3 bonded to the article.