Encapsulating Resin Composition for Low-Temperature Connector Potting
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Solution Overview
Problem
Existing encapsulating resin compositions face challenges in achieving stable low-temperature curing while maintaining storage stability, especially when used with thermoplastic resin connectors, which can lead to stress and peeling issues due to thermal expansion differences.
Innovation Solution
The encapsulating resin composition includes a curing accelerator, a thermosetting resin (specifically an epoxy resin), and an inorganic filler with a content of 50% to 95% by mass. This composition is characterized by a maximum heat release peak temperature between 100°C and 163°C and a half-value width of 5°C to 25°C in a DSC curve, optimizing low-temperature curing and storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a strongly active curing accelerator is used to achieve low-temperature curability, then the curing temperature can be reduced, but the storage stability of the encapsulating resin composition is lowered due to promoted reaction during storage
Solution Approach 1:
The patent changes the chemical parameters of the curing accelerator by selecting specific compounds (imidazole derivatives, guanidine derivatives, or phosphonium salts) with controlled activity levels. This allows achieving low-temperature curability (maximum heat release peak between 100-163°C) while maintaining storage stability through careful selection of accelerator type and content (0.1-5% by mass).
Solution Approach 2:
The patent creates a composite curing system combining epoxy resin (thermosetting resin) with specifically selected curing accelerators and curing agents. This composite material system achieves synergistic effects where the accelerator promotes low-temperature curing while the resin matrix maintains storage stability, resolving the contradiction between curing temperature and storage stability.
2Ease of manufacture
If the connector portion is heated to high temperature for encapsulating, then the encapsulating process can be completed, but stress occurs between the circuit board and the connector portion due to difference in linear expansion coefficient
Solution Approach 1:
The patent changes the temperature parameter of the encapsulating process by enabling curing at lower temperatures (100-163°C range) through the use of specifically selected curing accelerators. This reduces the thermal stress between the thermoplastic connector housing and the circuit board while still achieving complete encapsulation and curing.
3Strength
If a thermosetting resin is used as the encapsulating resin, then the encapsulating strength is improved, but peeling occurs at the interface between the thermoplastic connector and the circuit board
Solution Approach 1:
The patent changes the thermal and mechanical parameters of the encapsulating resin by formulating a thermosetting resin composition with specific properties (low curing temperature, controlled viscosity, appropriate crosslinking density) that enable strong adhesion to the thermoplastic connector interface while maintaining overall encapsulating strength.
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
This composition achieves stable low-temperature curing and improved storage stability, reducing the risk of peeling and stress between the circuit board and the connector, while maintaining the reliability and appearance of the electronic component.
Implementation Method 1
the encapsulating resin composition contains a curing accelerator, a thermosetting resin (A), and an inorganic filler, wherein the thermosetting resin (A) contains an epoxy resin
Implementation Method 2
in a differential scanning calorimetry (DSC) curve of the encapsulating resin composition obtained in a case where a temperature is increased from 30°C to 200°C
Implementation Method 3
the connector portion is heated to about 170°C to 180°C when encapsulating the connector portion with the resin, so that stress is likely to occur between the circuit board and the connector portion due to the difference in linear expansion coefficient
Data Source
Figure 1~2
AI summary
Provided is an encapsulating resin composition that is used for collectively encapsulating a circuit board (10) and at least a part of a connector portion (20), in which the encapsulating resin composition contains a curing accelerator, the connector portion (20) includes a terminal (21) that electrically connects the circuit board (10) with the external device, and a housing (22) that is disposed on an outer periphery of the terminal (21) and is encapsulated by the encapsulating resin composition, the housing (22) contains a thermoplastic resin, and in a differential scanning calorimetry (DSC) curve of the encapsulating resin composition obtained in a case where a temperature is increased from 30°C to 200°C under conditions of a temperature increase rate of 10°C/min using a DSC meter, a maximum heat release peak temperature is equal to or higher than 100°C and equal to or lower than 163°C, and a half-value width of a maximum heat release peak is equal to or higher than 5°C and equal to or lower than 25°C.