Curable Polyurethane Resin Composition for Electrical Device Sealing
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Solution Overview
Problem
Polyurethane resins used in electrical components, especially those with castor oil polyol, face degradation in high-temperature and high-moisture environments due to hydrolysis and hardening issues, leading to decreased physical properties and flexibility, which existing solutions like carbodiimide and epoxy compounds fail to adequately address without compromising compatibility and flexibility.
Innovation Solution
A curable polyurethane type resin composition combining castor oil-type polyol, polyisocyanate, and epoxidized acrylic polymer, where the epoxy groups in the acrylic polymer enhance hydrolysis resistance by forming new bonds with hydrolysis products, maintaining flexibility and durability in high-temperature environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbodiimide compounds are added to suppress hydrolysis, then hydrolysis resistance is improved, but compatibility with urethane raw material deteriorates and terminal functional groups are damaged
Solution Approach 1:
The patent introduces silane-modified epoxy compounds as intermediary substances that mediate between the hydrolysis suppression function and compatibility requirements. These compounds contain both epoxy groups (for hydrolysis suppression) and silane groups (for compatibility and crosslinking), serving as a bridge that resolves the contradiction between suppressing hydrolysis and maintaining raw material compatibility.
Solution Approach 2:
The patent modifies the chemical structure parameters of epoxy compounds by introducing silane groups, transforming them from conventional epoxy compounds with poor compatibility to silane-modified epoxy compounds with enhanced compatibility and crosslinking capability. This parameter change allows the same compound to fulfill multiple functions: suppressing hydrolysis, maintaining compatibility, and forming crosslinked structures.
2Reliability
If conventional epoxy compounds are added to suppress hydrolysis, then hydrolysis resistance is improved, but the cured substance becomes hard and flexibility decreases
Solution Approach 1:
The patent applies local quality by using silane-modified epoxy compounds that provide different functional properties at different molecular levels: the epoxy groups provide localized hydrolysis resistance at the molecular level, while the silane groups enable crosslinking that maintains overall flexibility at the macro level. This localized functional differentiation allows simultaneous achievement of hydrolysis resistance and flexibility.
Solution Approach 2:
The patent creates a composite molecular structure by combining silane groups and epoxy groups in the same compound. This composite structure allows the material to exhibit both the hydrolysis resistance of epoxy compounds and the flexibility maintained by silane crosslinking, effectively resolving the contradiction between hardness and flexibility.
3Quantity of substance
If castor oil polyol is used in polyurethane resins, then cost and insulating properties are improved, but the resin hardens over time in high temperature and undergoes hydrolysis in humid environments
Solution Approach 1:
The patent applies preliminary action by adding silane-modified epoxy compounds to the polyurethane resin system before curing. These compounds preemptively suppress hydrolysis of the castor oil polyol ester bonds and form crosslinked structures that prevent hardening. The preliminary presence of these compounds ensures that when exposed to high temperature and humidity, the resin maintains its physical properties without degradation.
Solution Approach 2:
The patent converts the harmful effect of ester bond hydrolysis into a beneficial crosslinking mechanism. The silane-modified epoxy compounds react with hydrolysis products (carboxyl groups) to form crosslinked structures, transforming the degradation pathway into a stabilizing mechanism that actually improves the resin's resistance to hydrolysis and maintains physical property stability.
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 effectively suppresses the softening of cured substances, maintains flexibility, and enhances the durability of electrical devices in high-temperature and high-moisture environments, providing superior hydrolysis resistance and improved physical properties.
Implementation Method 1
the backbone ester bonds undergo hydrolysis in atmospheres which include water causing the resin to soften
Implementation Method 2
epoxy groups can react with carbonate or both carbonate and alcohol which are generated through the hydrolysis of ester bonds derived from castor oil-type polyol and thus form new bonds
Implementation Method 3
the reaction of castor oil-type polyol and polyisocyanate to form urethane bonds
Data Source
AI summary
A curable polyurethane type resin composition which is applicable for a sealing material for an electrical device used in a vehicle, enhances a hydrolysis resistance of a cured substance and can suppress a decrease in physical properties in high temperature and high moisture environments. The curable polyurethane type resin composition contains castor oil-type polyol, polyisocyanate, and epoxidized acrylic polymer. The electrical device has electrical components covered with a sealing material consisting of a cured substance of the curable polyurethane-type resin composition.