Resin Composition for Vehicle Electronic Control Units
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Solution Overview
Problem
Existing resin compositions for encapsulating on-vehicle electronic control units face challenges in achieving a balance between filling properties and adhesiveness to wiring substrates, often resulting in unfilled portions like weld voids and decreased adhesiveness due to differences in flow properties and the presence of silicone compounds in solder resist layers.
Innovation Solution
A resin composition containing a thermosetting resin, imidazoles as a curing catalyst, and a curing agent, with specific torque measurement conditions to control the behavior of the resin, ensuring a balance between filling properties and adhesiveness, is developed. This composition includes a thermosetting resin content of 2-50% and imidazoles at 0.01-2.0% by mass, with a curing agent at 1-40% by mass, and is characterized by a torque value change under controlled conditions to enhance encapsulation quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the resin composition is optimized for filling properties, then the encapsulation completeness improves, but the adhesiveness to wiring substrate deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the content ratios of thermosetting resin (2-50 mass%), curing agent (1-40 mass%), and imidazoles (0.01-2.0 mass%), along with regulating the torque value parameters (T1: 15-100 seconds, minimum torque: 0.5-2.5 N·m). These parameter optimizations enable the resin composition to achieve both excellent filling properties and adhesiveness to wiring substrate simultaneously, resolving the technical contradiction between encapsulation completeness and bonding strength.
2Strength
If the resin composition is optimized for adhesiveness to wiring substrate, then the bonding strength improves, but the filling properties deteriorate
Solution Approach 1:
The patent resolves this contradiction through parameter changes by establishing specific content ranges for thermosetting resin (2-50 mass%), curing agent (1-40 mass%), and imidazoles (0.01-2.0 mass%), combined with torque value control (T1: 15-100 seconds, minimum torque: 0.5-2.5 N·m). This balanced parameter configuration enables the resin to exhibit both strong adhesiveness to wiring substrate and excellent filling properties, preventing the trade-off between bonding strength and encapsulation completeness.
3Ease of manufacture
If silicone compounds are added to solder resist layer, then the solderability improves, but the adhesiveness of encapsulating resin deteriorates
Solution Approach 1:
The patent applies the intermediary principle by introducing imidazoles as a curing catalyst that mediates between the silicone-containing solder resist layer and the encapsulating resin. The imidazoles (0.01-2.0 mass%) facilitate crosslinking reactions that enhance adhesion despite the presence of silicone compounds, allowing the encapsulating resin to maintain strong bonding to the wiring substrate even when solderability is improved through silicone addition.
Solution Approach 2:
The patent resolves this contradiction through parameter changes by optimizing the curing agent content (1-40 mass%) and imidazoles content (0.01-2.0 mass%), along with controlling the torque minimum value (0.5-2.5 N·m). These parameter adjustments enable the encapsulating resin to overcome the adhesion-reducing effect of silicone compounds while maintaining solderability, achieving both goals simultaneously.
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 resin composition effectively improves the balance between filling properties and adhesiveness to the wiring substrate, preventing unfilled portions and ensuring reliable encapsulation, even with silicone-containing solder resist layers, thereby enhancing the reliability and temperature cycle resistance of on-vehicle electronic control units.
Implementation Method 1
imidazoles as a curing catalyst in a content of greater than or equal to 0.01 mass% and less than or equal to 2.0 mass% with respect to the total resin composition for encapsulating
Implementation Method 2
a thermosetting resin in a content of greater than or equal to 2 mass% and less than or equal to 50 mass% with respect to the total resin composition for encapsulating; and a curing agent in a content of greater than or equal to 1 mass% and less than or equal to 40 mass% with respect to the total resin composition for encapsulating
Data Source
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AI summary
Provided is a resin composition for encapsulating which is used for forming an encapsulating resin of an on-vehicle electronic control unit including a wiring substrate, a plurality of electronic components mounted on the wiring substrate, and the encapsulating resin encapsulating the electronic component, the resin composition including: a thermosetting resin; and imidazoles, in which when a torque value is measured over time under conditions of the number of rotations of 30 rpm and a measurement temperature of 175°C by using Labo Plastomill, a time T1 at which the torque value is less than or equal to 2 times a minimum torque value is longer than or equal to 15 seconds and shorter than or equal to 100 seconds, and the minimum torque value is greater than or equal to 0.5 N·m and less than or equal to 2.5 N·m.