Core-Shell Polymer Particle Epoxy Resin Storage Stability
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Solution Overview
Problem
The existing curable resin compositions containing epoxy resin suffer from poor storage stability and insufficient impact and peel-resistant adhesion, particularly when fumed silica is added, leading to increased viscosity over time, which affects the compatibility of impact and peel-resistant adhesion and storage stability in structural adhesives for vehicles.
Innovation Solution
A curable resin composition is developed with a core-shell structured polymer fine particle having diene rubber as the core layer and fumed silica as the inorganic filler, where the epoxy group content is limited to 0.01 to 0.2 mmol/g, and optionally includes bisphenol A epoxy resin and rubber-modified or urethane-modified epoxy resin, to achieve thixotropy and improved adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fumed silica is added to the curable resin composition to improve thixotropy and adhesion, then T peel adhesion and impact resistance are improved, but viscosity increases over time during storage
Solution Approach 1:
The patent controls the epoxy group content of polymer fine particles within a specific range (0.01 to 0.2 mmol/g) to optimize the balance between adhesion improvement and viscosity control. This parameter optimization prevents excessive crosslinking during storage while maintaining adequate adhesion performance.
Solution Approach 2:
The patent uses a composite system comprising polymer fine particles with controlled epoxy groups, fumed silica, and epoxy resin. The polymer fine particles act as a intermediary that enhances the compatibility between fumed silica and epoxy resin, preventing excessive aggregation and viscosity increase while maintaining adhesion improvement.
2Strength
If polymer fine particles with epoxy groups are added to improve adhesion, then T peel adhesion is enhanced, but the composition becomes less stable during storage
Solution Approach 1:
The patent precisely controls the epoxy group content of polymer fine particles within 0.01 to 0.2 mmol/g. This controlled low level provides sufficient adhesion enhancement through interfacial bonding while minimizing premature crosslinking reactions during storage that would compromise 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 exhibits excellent thixotropy and storage stability, enhancing T peel adhesion and impact and peel-resistant adhesion of the cured product, while maintaining the balance between viscosity and physical properties.
Implementation Method 1
The composition exhibits excellent thixotropy and storage stability
Data Source
AI summary
A curable resin composition of the present invention contains 1 to 100 parts by mass of a polymer fine particle (B) relative to 100 parts by mass of an epoxy resin (A), wherein the polymer fine particle has a core-shell structure, the core layer of the polymer fine particle is diene rubber, the content of the epoxy group of the polymer fine particle (B) is 0.01 to 0.15 mmol/g. A curable resin composition (I) of the first embodiment contains 0.5 to 30 parts by mass of fumed silica as an inorganic filler (C). In addition, a curable resin composition (II) of the second embodiment contains bisphenol A epoxy resin and rubber-modified epoxy resin and/or urethane-modified epoxy resin as the epoxy resin (A).