Soluble Polyimide Coatings on Low Tg Substrates
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Solution Overview
Problem
Existing polyimides are expensive and unsuitable for large-scale applications due to high production costs, and they cannot be easily applied to polymeric substrates with lower glass transition temperatures (Tg) or melting temperatures (Tm) without undergoing costly cure or dehydration processes.
Innovation Solution
A composition comprising 3-30 weight percent polyimide, cyclopentanone as a solvent in amounts of at least 70 weight percent, and 0-15 weight percent of one or more pigments, which allows for the formation of a solid film on a substrate with a thickness of 1 to 5 micrometers, suitable for low Tg or Tm polymeric substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyimides are used as coating layers, then excellent electrical insulation properties and dielectric strength are achieved, but high production costs make them uneconomical for large scale applications
Solution Approach 1:
The patent changes the chemical structure parameters of polyimides by introducing aliphatic cyclic groups (cycloaliphatic dianhydrides and cycloaliphatic diamines) to create soluble polyimides that can be processed at lower costs while maintaining electrical insulation properties
Solution Approach 2:
The patent uses cost-effective cycloaliphatic monomers and simple coating processes to create economical polyimide coatings that achieve the desired electrical insulation without requiring expensive processing conditions
2Reliability
If polyimides are formed by cure or dehydration of polyamic acids, then polyimide films are successfully formed, but elevated temperatures required make them unsuitable for low Tg or Tm polymeric substrates
Solution Approach 1:
The patent changes the physical state parameter of polyimides from insoluble to soluble by using cycloaliphatic monomers, enabling processing at room temperature or low temperatures without cure or dehydration steps
Solution Approach 2:
The patent extracts the need for high-temperature cure or dehydration processes by designing polyimides that are inherently soluble and can be applied directly as coatings at low temperatures
3Reliability
If conventional polyimides are applied to substrates, then electrical insulation is achieved, but the substrate must have high Tg or Tm to withstand processing temperatures
Solution Approach 1:
The patent changes the processing temperature parameter from high to low by using soluble polyimides, expanding substrate compatibility to include low Tg or Tm polymers
Solution Approach 2:
The patent creates polyimides with universal applicability across diverse substrates by eliminating the temperature constraint, allowing use on both high Tg and low Tg polymeric substrates
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 solution enables the economical use of polyimides in large-scale applications and allows for the application of polyimide films on low Tg or Tm polymeric substrates, maintaining excellent electrical insulation properties and dielectric strength.
Implementation Method 1
the polyimide is soluble in the cyclopentanone at room temperature in the range of 5 to 30 weight percent
Implementation Method 2
drying form a solid film on the substrate having a thickness of 1 to 5 micrometers
Data Source
AI summary
A method comprises providing a substrate, coating onto the substrate a composition comprising 3-30 weight percent based on total weight of the composition of a polyimide; a solvent comprising cyclopentanone in an amount of at least 70, preferably at least 80, more preferably at least 90 weight percent based on total weight of the solvent; and 0-15 weight % of one or more pigments, wherein the polyimide is soluble in the cyclopentanone at room temperature in the range of 5 to 30 weight percent, drying form a solid film on the substrate having a thickness of 1 to 5 micrometers. A composition useful in such method and an article made from such method are also disclosed.