Boron Trichloride-Amine Accelerator for Epoxy Resin Cure
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Solution Overview
Problem
The cure of thermosets based on polyfunctional isocyanates with standard mono- or polyfunctional epoxy resins is too slow for industrial applications, even with existing accelerator systems, resulting in demold times of 15 minutes to one hour at moderate cure temperatures of 90°C to 120°C.
Innovation Solution
An accelerator composition comprising a boron trichloride-amine complex and a quaternary ammonium or phosphonium halide is used to accelerate the pre-cure of polyfunctional isocyanates with epoxy resins, achieving rapid demold times without excessively increasing viscosity or affecting post-cure times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If known accelerator systems are used to speed up the cure of polyfunctional isocyanates with epoxy resins, then the pre-cure time is reduced, but the viscosity builds up too quickly preventing proper mold filling
Solution Approach 1:
The accelerator system is divided into two separate components: a boron trichloride-amine complex and a quaternary ammonium or phosphonium halide. Each component performs a distinct function - the boron complex provides temperature-latent acceleration with controlled viscosity buildup, while the quaternary ammonium/phosphonium halide enhances pre-cure speed without causing excessive gelation. This segmentation allows independent optimization of each accelerator's properties to resolve the contradiction between fast pre-cure and manageable viscosity.
Solution Approach 2:
The invention uses a composite accelerator system combining two chemically distinct compounds (boron trichloride-amine complex and quaternary ammonium/phosphonium halide) in specific weight ratios (1:1 to 10:1). This composite approach creates synergistic effects where the combination achieves faster pre-cure times than either component alone, while the boron complex moderates the viscosity buildup that would otherwise occur with quaternary ammonium/phosphonium halides alone.
2Loss of time
If a fast accelerator is used to reduce pre-cure time, then demold time is reduced, but the post-cure temperature remains too high for industrial applications
Solution Approach 1:
The invention changes the chemical parameters of the accelerator system by selecting specific compounds with appropriate reactivity and thermal properties. The boron trichloride-amine complex is chosen for its temperature-latent characteristics and ability to catalyze oxazolidone formation at lower temperatures, while the quaternary ammonium/phosphonium halide is selected for its fast pre-cure action. The specific weight ratios (1:1 to 10:1) are optimized to balance pre-cure speed with post-cure temperature reduction, achieving demold times of several minutes while keeping post-cure temperatures suitable for industrial applications.
3Ease of manufacture
If standard epoxy resins are used with polyfunctional isocyanates, then the system is simple and easy to manufacture, but the cure time is too slow for industrial applications
Solution Approach 1:
The invention introduces an intermediary accelerator composition consisting of a boron trichloride-amine complex and a quaternary ammonium or phosphonium halide. This intermediary substance mediates between the standard epoxy resin-polyfunctional isocyanate system (which is simple but slow) and the requirement for fast industrial curing. The accelerator composition acts as a catalyst that speeds up the reaction without requiring changes to the base resin or isocyanate system, thus maintaining simplicity while dramatically improving cure speed to achieve demold times of several minutes.
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 accelerator composition significantly reduces pre-cure times to several minutes at 90°C to 120°C while maintaining unchanged post-cure times, making it suitable for industrial applications without the drawbacks of single-component accelerators.
Implementation Method 1
an accelerator composition for the cure of polyfunctional isocyanates with epoxy resins comprising (a) a boron trichloride-amine complex, and (b) a quaternary ammonium or phosphonium halide
Data Source
Figure 1~2
AI summary
The present disclosure is related to an accelerator composition for the cure of polyfunctional isocyanates with epoxy resins comprising (a) a boron trihalide-amine complex, and (b) a quaternary ammonium or phosphonium halide as well as the use of such accelerator composition, cured isocyanate-epoxy resin products obtainable therefrom and a method of making a cured isocyanate-epoxy resin product.