Silane-Modified Primer for Capacitor Adhesion
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Solution Overview
Problem
Existing processes for producing solid electrolytic capacitors face challenges in achieving low equivalent series resistance (ESR), low residual current, and high thermal stability, particularly due to issues with edge and corner coverage of the polymeric outer layer, which often require the use of strongly acidic compounds that can cause corrosion.
Innovation Solution
A process involving the application of a di- or polyfunctional monomeric compound with an amine group and a carboxylic or sulfonic acid group as a primer, followed by a conjugated polymer solution, eliminates the need for strongly acidic compounds like p-toluenesulfonic acid or sulfuric acid, enhancing edge and corner coverage without compromising thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polymeric outer layer is applied to improve edge and corner coverage, then mechanical protection and self-healing behavior are improved, but the application process becomes more complex and may require strongly acidic compounds that cause corrosion
Solution Approach 1:
A primer layer comprising silane-modified polyethyleneimine is applied as an intermediary between the capacitor anode and the conjugated polymer outer layer. This primer facilitates adhesion and enables the outer layer to be applied without requiring strongly acidic compounds, thus improving edge and corner coverage while avoiding corrosion issues and simplifying the overall process
Solution Approach 2:
The invention changes the chemical parameters of the application process by using a silane-modified polyethyleneimine primer instead of strongly acidic compounds. This parameter change allows the conjugated polymer to be applied under milder conditions, improving reliability without increasing process complexity
2Reliability
If strongly acidic compounds like p-toluenesulfonic acid or sulfuric acid are used to enhance edge and corner coverage, then coverage is improved, but thermal stability is compromised due to corrosion
Solution Approach 1:
The silane-modified polyethyleneimine primer acts as a protective intermediary that enables the application of the conjugated polymer outer layer without using strongly acidic compounds. This eliminates the corrosion risk to the oxide layer while maintaining excellent edge and corner coverage, thus preserving thermal stability
Solution Approach 2:
The invention converts the potential harm of acid corrosion into a benefit by using a basic silane-modified polyethyleneimine primer that not only prevents corrosion but also enhances adhesion and promotes uniform coverage of the outer layer, improving both reliability and thermal stability
3Reliability
If multiple coating cycles are used to form a thick polymeric outer layer, then coverage is improved, but the layer becomes inhomogeneous and the process becomes more complex
Solution Approach 1:
The silane-modified polyethyleneimine primer serves as an effective intermediary that enables single-step application of the conjugated polymer outer layer with uniform coverage. The primer's adhesion-promoting properties eliminate the need for multiple coating cycles, reducing process complexity while maintaining excellent coverage
Solution Approach 2:
The primer is applied in advance to prepare the surface for optimal outer layer deposition. This preliminary action ensures that a single coating cycle produces homogeneous coverage, eliminating the need for repeated coating cycles and simplifying the manufacturing process
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 approach results in solid electrolytic capacitors with low ESR, low residual current, and high thermal stability, improving their performance and reliability in electronic circuits.
Implementation Method 1
a) a primer layer is applied to the capacitor anode, in particular to the solid electrolyte
Implementation Method 2
followed by an at least partial removal of the solvent or dispersant d) for the formation of the polymeric outer layer
Implementation Method 3
The conductive polymeric outer layer itself should have so-called self-healing behavior: minor defects in the dielectric on the outer anode surface, which occur in spite of the buffer effect, are electrically insulated by virtue of the conductivity of the outer layer being destroyed by the electrical current at the defect site
Implementation Method 4
an oxide layer present on the metal surface
Data Source
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AI summary
The present invention relates to a process for producing an electrolytic capacitor, the process comprising process steps i) ii): i) providing a capacitor body (1) that comprises - an electrode body (2) of an electrode material, - a dielectric (3) which at least partially covers the surface of this electrode material, and - a solid electrolyte (4) at least comprising an electrically conductive material which at least partially covers the dielectric surface; ii) applying at least one primer compound e) to the capacitor body (1), followed by an application of a solution or dispersion a) comprising a conjugated polymer b) and a solvent or dispersant d), followed by an at least partial removal of the solvent or dispersant d) for the formation of the polymeric outer layer (5) that is formed onto the capacitor body (1); wherein the primer compound e) is a di- or polyfunctional monomeric compound comprising at least one amine group, which optionally may be protonated, and at least one carboxylic or sulfonic acid group, which optionally may be deprotonated. The invention also relates to electrolytic capacitors produced by this process and to the use of such electrolytic capacitors.