Direct Overmolding Epoxy Resin for Switch Gears
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Solution Overview
Problem
Current methods for encapsulating electrical components, such as vacuum switch gears, face challenges in achieving sufficient thermal cycle crack resistance and are economically and time-consuming, with existing filler combinations being costly or inefficient.
Innovation Solution
A curable epoxy resin composition combining wollastonite and amorphous silica as fillers, surface-treated with silanes, is applied directly to ceramic housings of switch gears, providing enhanced mechanical properties and thermal cycle crack resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass balls are used as fillers for direct encapsulation, then crack resistance is improved, but production cost increases and mechanical destruction occurs during mixing
Solution Approach 1:
The patent replaces expensive glass balls with inexpensive natural fillers (quartz sand, gravel, crushed stone) that can be readily obtained and processed. These conventional construction materials provide sufficient crack resistance without the high cost and mechanical fragility of glass spheres, making the manufacturing process more economical and less prone to filler destruction during mixing
Solution Approach 2:
The patent modifies the filler particle size parameters to optimize performance. By specifying gravel with 80-100% of particles between 0.63-2.0 mm and crushed stone with 80-100% of particles between 2.0-4.0 mm, the formulation achieves optimal balance between crack resistance, packing density, and resistance to mechanical destruction during processing
2Reliability
If elastomeric cushioning is added to absorb thermal stresses, then crack resistance is improved, but the number of process steps increases and production time is extended
Solution Approach 1:
The patent merges the cushioning function into the epoxy resin matrix itself by incorporating flexible polymers (polybutadiene, polyisoprene, or silicone rubber) as modifiers. This eliminates the separate elastomeric cushioning layer and its associated processing steps, while still providing thermal stress absorption and crack resistance in the encapsulating material
Solution Approach 2:
The patent creates a composite epoxy resin system combining rigid epoxy matrix with flexible polymer modifiers and inorganic fillers. This composite structure provides both the mechanical strength of epoxy and the thermal stress absorption of elastomers, achieving crack resistance through material composition rather than multi-layer construction
3Reliability
If core/shell polymer and rubber particles are used as fillers, then thermal cycle crack resistance is improved, but material cost increases significantly
Solution Approach 1:
The patent replaces expensive core/shell polymers and rubber particles with inexpensive natural inorganic fillers (quartz sand, gravel, crushed stone) combined with affordable epoxy resin. This substitution dramatically reduces material cost while maintaining adequate crack resistance through proper filler sizing and epoxy formulation
Solution Approach 2:
The patent achieves crack resistance not through expensive universal filler replacement but through optimized local properties: using gravel (0.63-2.0 mm) and crushed stone (2.0-4.0 mm) with specific size distributions that provide interlocking structure and stress distribution, combined with epoxy resin modifiers that locally enhance flexibility at crack initiation sites
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 demonstrates improved thermal cycle crack resistance, reducing the need for additional cushioning and process steps, making it suitable for high-performance electrical components with lower production costs and increased efficiency.
Implementation Method 1
A curable epoxy resin composition combining wollastonite and amorphous silica as fillers, surface-treated with silanes
Implementation Method 2
A curable epoxy resin composition... is applied directly to ceramic housings of switch gears
Data Source
AI summary
Disclosed is a curable composition comprising an epoxy resin and a filler composition, a cured product obtained by curing said curable composition as well as the use of the cured products as electrically insulating construction material for electrical or electronic components.