Epoxy Adhesive with Pyrazine Amine for Low-Temperature Curing
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Solution Overview
Problem
Conventional epoxy resin-based low-temperature curable compositions for automobiles face challenges in achieving good low-temperature curability, storage stability, and adhesion, with existing combinations often compromising on one or more of these properties.
Innovation Solution
A curable composition comprising an epoxy resin, a urea-based curing accelerator (such as N, N-dimethyl-N′-(3,4-dichlorophenyl) urea), and an amine-based curing agent with a pyrazine ring, specifically formulated to balance low-temperature curability, storage stability, and adhesion by optimizing the mass ratios and content percentages of these components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional latent curing agent and curing accelerator combinations are used to achieve low-temperature curability, then low-temperature curability is improved, but storage stability is reduced
Solution Approach 1:
The invention changes the chemical parameters of the curing system by selecting specific curing agents (amines with pKa 7.0-10.0) and accelerators (ureas with pKa 3.0-6.0) whose physical-chemical properties enable low-temperature reactivity while maintaining storage stability. This parameter optimization allows curing at 100-160°C without compromising storage characteristics.
Solution Approach 2:
The invention creates a composite curing system combining multiple components: epoxy resin, specific amine curing agents, urea accelerators, and optional modifiers. This composite approach synergistically improves both low-temperature curability and storage stability, overcoming the limitations of single-component systems.
2Productivity
If curing is performed at lower temperature and shorter time to reduce manufacturing cost, then productivity is improved, but adhesion is reduced
Solution Approach 1:
The invention optimizes curing parameters (temperature 100-160°C, time 5-30 minutes) by selecting curing agents and accelerators with appropriate reactivity. The specific pKa ranges of amines (7.0-10.0) and ureas (3.0-6.0) enable complete curing at lower temperatures and shorter times while maintaining strong adhesion to steel sheets.
Solution Approach 2:
The urea-based accelerator acts as an intermediary that facilitates the curing reaction between epoxy resin and amine curing agent at lower temperatures. This mediator enables the curing process to proceed efficiently at 100-160°C, achieving both high productivity and good adhesion.
3Adaptability or versatility
If conventional adhesives are used in lower surrounding parts and overlapped portions, then application scope is expanded, but sufficient curability cannot be ensured
Solution Approach 1:
The invention modifies the curing system parameters to achieve effective curing at lower temperatures (100-160°C) suitable for automobile lower surrounding parts and overlapped portions. The selected amine-urea combination provides sufficient reactivity at these reduced temperatures, ensuring complete curability in previously difficult-to-cure locations.
Solution Approach 2:
The invention creates a dynamic curing system that adapts to different application conditions. The accelerator-curing agent combination provides progressive reactivity that ensures complete curing whether applied to lower surrounding parts, overlapped portions, or conventional areas, making the adhesive universally applicable throughout the automobile structure.
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 excellent low-temperature curability, storage stability, and adhesion, making it suitable for use in automobile manufacturing, particularly in lower surrounding parts and overlapped steel sheet applications, while considering environmental and cost reduction factors.
Implementation Method 1
a curable composition comprising an epoxy resin, a urea-based curing accelerator (A) and an amine-based curing agent (B) having a pyrazine ring
Data Source
AI summary
The present invention provides an epoxy resin-based curable composition which may be used as a structural adhesive for an automobile. Particularly, the present invention provides an epoxy resin-based curable composition having excellent low-temperature curability, while maintaining good storage stability and good adhesion.The present invention relates to a curable composition comprising an epoxy resin, a urea-based curing accelerator (A) and an amine-based curing agent (B) having a pyrazine ring.