Conductive Paste Composition for Humidity-Resistant Capacitor Films
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Solution Overview
Problem
Existing conductive pastes used in solid electrolytic capacitor elements fail to adequately suppress silver ionization and migration in high humidity environments, leading to reliability issues such as short circuits.
Innovation Solution
A polymer type conductive paste containing conductive metal powder, polyvinyl butyral resin, and specific additives like stearic acid or octadecyl butanedioic acid, with controlled hydroxyl group content, is used to form a conductor layer that reduces moisture permeability and ionization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional conductive paste with silver powder and polyvinyl butyral resin is used, then the conductor layer provides good electrical conductivity, but silver ionization and migration occur in high humidity environments leading to short circuits
Solution Approach 1:
The patent introduces a silane coupling agent as an intermediary substance between the polyvinyl butyral resin and silver powder. This coupling agent forms a protective interface that prevents direct contact between moisture and the silver-polymer interface, thereby suppressing silver ionization while maintaining electrical conductivity. The coupling agent acts as a mediator that blocks the harmful interaction between humidity and the conductive components.
Solution Approach 2:
The patent creates a composite conductive paste system comprising polyvinyl butyral resin, silver powder, and silane coupling agent. This composite material combines the electrical conductivity of silver with the adhesive properties of the resin, while the silane coupling agent provides moisture resistance. The synergistic combination of these materials achieves both good conductivity and high reliability in humid environments.
2Ease of manufacture
If polyvinyl butyral resin with high hydroxyl group content is used, then the paste has good adhesion and processability, but moisture permeability increases leading to silver migration
Solution Approach 1:
The patent changes the chemical parameter of the resin system by introducing silane coupling agent, which modifies the hydroxyl group content and molecular structure. This parameter change reduces moisture permeability while preserving the adhesion and processability benefits of polyvinyl butyral resin. The silane modification transforms the resin's properties to achieve both manufacturability and moisture 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 conductor layer formed by this paste exhibits low moisture permeability, effectively suppressing silver ionization and ensuring high reliability even in high humidity conditions.
Implementation Method 1
the moisture permeability of the conductor layer can be reduced, thereby suppressing the ionization of silver
Data Source
AI summary
This invention provides a polymer type conductive paste that can provide a highly reliable conductive layer even in high humidity environments. The polymer type conductive paste in accordance with the embodiment of the present invention contains conductive metal powder, binder resin, organic solvent, and specific additives, wherein said binder resin is polyvinyl butyral resin, wherein said specific additives are one or more selected from the group consisting of stearic acid, lauric acid, octadecyl butanedioic acid, benzoic acid, acetamidophenol, aminophenol, catechol, and N,N-bis(2-hydroxyethyl) coco alkylamine, and wherein said specific additives are contained at the content of not less than 0.01 parts by mass and not more than 3.0 parts by mass per 100 parts by mass of said conductive metal powder.