Capacitor Housing Polyester Composition for Adhesion and Hydrolysis Resistance
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Solution Overview
Problem
Existing capacitor housing materials face challenges in achieving high adhesion to epoxy potting materials, poor hydrolysis resistance, and insufficient dimensional stability, particularly with polybutylene terephthalate (PBT)-based materials.
Innovation Solution
A polyester resin composition comprising polybutylene terephthalate (PBT) resin, acrylic styrene acrylonitrile (ASA) resin, glass fiber, epoxy resin, carbodiimide-based anti-hydrolysis agent, and epoxy silane is formulated to enhance adhesion, hydrolysis resistance, and dimensional stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polybutylene terephthalate (PBT)-based materials are used to improve adhesion to epoxy potting materials, then adhesion is improved, but hydrolysis resistance deteriorates
Solution Approach 1:
The patent uses a composite material system combining PBT resin with ASA resin, glass fiber, epoxy resin, carbodiimide-based anti-hydrolysis agent, and epoxy silane. This composite approach allows the material to simultaneously achieve high adhesion to epoxy potting materials and excellent hydrolysis resistance, resolving the contradiction between adhesion improvement and hydrolysis resistance deterioration
Solution Approach 2:
The patent modifies the chemical parameters of the PBT-based material by adding specific components: carbodiimide-based anti-hydrolysis agent (0.01-1% by weight) to improve hydrolysis resistance, epoxy resin (1-3% by weight) and epoxy silane (0.01-1% by weight) to enhance adhesion to epoxy potting materials. These parameter changes allow simultaneous achievement of both adhesion and hydrolysis resistance
2Stability of the object's composition
If a large amount of minerals is added to improve dimensional stability, then dimensional stability is improved, but viscosity increases making it difficult to include high content of filler
Solution Approach 1:
The patent employs a composite material system where glass fiber (25-35% by weight) provides dimensional stability while the PBT-ASA resin matrix maintains appropriate viscosity. The combination of PBT resin (40-50% by weight) and ASA resin (18-20% by weight) creates a balanced formulation that achieves dimensional stability through mineral content without excessive viscosity increase
Solution Approach 2:
The patent optimizes the parameter balance between filler content and viscosity by controlling the resin composition. The specific formulation with PBT resin having intrinsic viscosity of 0.80-1.00 dl/g, combined with ASA resin and controlled amounts of glass fiber, achieves dimensional stability while maintaining manufacturability by keeping viscosity at acceptable levels
3Stability of the object's composition
If polyphenylene sulfide (PPS)-based resin with high content of filler is used, then dimensional stability is improved, but adhesion to epoxy potting material deteriorates
Solution Approach 1:
The patent introduces epoxy resin and epoxy silane as intermediary substances that mediate between the PBT-based molded article and the epoxy potting material. These intermediaries chemically bond to both the substrate and the potting material, achieving strong adhesion while maintaining the dimensional stability provided by the glass fiber-reinforced PBT-ASA composite structure
4Stability of the object's composition
If filler content is increased to improve dimensional stability, then dimensional stability is improved, but hydrolysis resistance deteriorates
Solution Approach 1:
The patent uses carbodiimide-based anti-hydrolysis agent as an intermediary substance that protects the interface between the filler and the resin matrix. This agent prevents water from penetrating and causing hydrolysis at the filler-resin interface, allowing high glass fiber content (25-35% by weight) to be used for dimensional stability without compromising hydrolysis resistance
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 high initial adhesive strength, maintains strength in harsh environments, and ensures excellent dimensional stability, reducing manufacturing costs while maintaining mechanical properties.
Implementation Method 1
0.01 to 1% by weight of a carbodiimide-based anti-hydrolysis agent
Implementation Method 2
1 to 3% by weight of epoxy resin; 0.01 to 1% by weight of epoxy silane
Data Source
AI summary
A polyester resin composition that has excellent adhesion to an epoxy potting material and can simultaneously satisfy dimensional stability and hydrolysis resistance, and a molded article for capacitor housing, which is manufactured using the polyester resin composition. The polyester resin composition including 40 to 50% by weight of polybutylene terephthalate resin, 18 to 20% by weight of acrylic styrene acrylonitrile resin, 25 to 35% by weight of glass fiber, 1 to 3% by weight of epoxy resin, 0.01 to 1% by weight of a carbodiimide-based anti-hydrolysis agent, and 0.01 to 1% by weight of epoxy silane.