Polyvinyl Alcohol Resin for High-Temperature Capacitor Films
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Solution Overview
Problem
Conventional polyvinyl alcohol resins used in film capacitors exhibit insufficient capacitance retention at high temperatures and have limitations in thickness reduction due to low permittivity and heat-resistant temperature, making them unsuitable for high-temperature applications like electric vehicles.
Innovation Solution
A polyvinyl alcohol resin with specific permittivity ratios (A ≥ 3.0, 1.0 ≥ B / A ≥ 0.6) and a solubility parameter of 12 or greater, incorporating functional groups such as carboxylic acid, sulfonic acid, pyrrolidone ring, amide, or amino groups, produced using continuous stirred-tank reactors to maintain performance stability at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polyvinyl alcohol resins are used for film capacitors, then the film can be produced with aqueous solvent, but the capacitance retention at high temperature is insufficient
Solution Approach 1:
The patent modifies the chemical structure of polyvinyl alcohol resin by introducing specific functional groups (carboxylic acid, sulfonic acid, pyrrolidone ring, amide, or amino groups) to change its permittivity and temperature stability parameters, thereby improving capacitance retention at high temperatures while maintaining aqueous solvent compatibility
Solution Approach 2:
The patent creates a composite resin structure by combining polyvinyl alcohol base polymer with functional groups or monomers that have high permittivity and thermal stability, achieving both high capacitance retention and processability in aqueous solvent
2Quantity of substance
If conventional polyvinyl alcohol resins are used, then the film can be formed with aqueous solvent, but the permittivity is low leading to larger capacitor size
Solution Approach 1:
The patent increases the permittivity parameter of the resin by incorporating functional groups with high dielectric constant, which directly increases capacitance value for a given geometry, thereby reducing the required capacitor size
3Temperature
If OPP films are used for dielectric sheets, then the film can be produced, but the heat-resistant temperature is low causing permittivity change at high temperature
Solution Approach 1:
The patent changes the thermal stability parameter of the resin by introducing functional groups with high glass transition temperatures and strong intermolecular forces, enabling the film to maintain permittivity stability at high temperatures up to 125°C or higher
4Length of moving object
If OPP films are used, then the film can be produced by stretching, but thickness reduction is limited
Solution Approach 1:
The patent replaces the mechanical stretching process used for OPP films with a solution casting method using aqueous solvent, allowing the film to be formed by solvent evaporation and drying, which enables much thinner film production without the thickness limitations of stretching processes
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 enables the production of films with high capacitance retention and excellent strength and flexibility, maintaining performance stability even at high temperatures.
Implementation Method 1
where A is a permittivity at 25°C measured at 1 kHz, and B is a permittivity at 125°C measured at 1 kHz
Data Source
AI summary
The present invention provides a polyvinyl alcohol resin that can provide a film having high capacitance retention at high temperature and having excellent strength and flexibility. Provided is a polyvinyl alcohol resin satisfying the following formulas (1) and (2): A≥3.0 1.0≥B/A≥0.6 where A is a permittivity at 25°C measured at 1 kHz, and B is a permittivity at 125°C measured at 1 kHz.