Polyimide Precursor Composition with Thermal Imidization Accelerator
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Solution Overview
Problem
Existing polyimide precursor compositions face challenges in achieving high imidization degrees at lower temperatures for polyamic acid esters, which can lead to reduced molecular weight and impaired film properties, and also struggle with adhesion to inorganic substrates when using silane coupling agents.
Innovation Solution
A polyimide precursor composition comprising a polyamic acid ester and a specific compound with carboxy and amino/imino groups that deprotect to enhance basicity upon heating, combined with a silane coupling agent, to accelerate thermal imidization and improve substrate adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polyamic acid is used as polyimide precursor and baked for imidization, then imidization proceeds easily, but reverse reaction occurs reducing molecular weight and impairing film properties
Solution Approach 1:
The patent extracts the problematic carboxyl group from the polyamic acid structure by converting it to a polyamic acid ester. This is achieved by reacting polyamic acid with an alcohol in the presence of a condensing agent, thereby removing the source of reverse reaction while maintaining the imidization capability through the ester group.
Solution Approach 2:
The patent creates a composite system by combining polyamic acid ester with specific additives including a compound having both carboxyl and amino groups, and a silane coupling agent. This composite approach allows the polyamic acid ester to provide stable molecular weight while the additives facilitate imidization and improve substrate adhesion.
2Reliability
If polyamic acid ester is used as polyimide precursor, then molecular weight stability is maintained, but imidization temperature must be higher than for polyamic acid
Solution Approach 1:
The patent introduces a compound having both carboxyl and amino groups as an intermediary substance that mediates the imidization reaction of polyamic acid ester. This intermediary acts as a catalyst or reaction promoter, enabling the ester group to undergo imidization at lower temperatures while maintaining molecular weight stability, thus bridging the gap between the two precursor types.
Solution Approach 2:
The patent changes the chemical parameters of the system by adding compounds with specific functional groups (carboxyl and amino groups) that alter the reaction characteristics. These parameter changes enable the polyamic acid ester to achieve imidization at lower temperatures by modifying the reaction mechanism through the introduced functional groups.
3Strength
If silane coupling agent is added to improve adhesion to inorganic substrates, then adhesion is enhanced, but effectiveness may be compromised in polyamic acid ester systems
Solution Approach 1:
The patent achieves universality by combining silane coupling agent with a compound having both carboxyl and amino groups. This combination creates a multi-functional system where the silane coupling agent provides substrate adhesion while the amino-containing compound facilitates imidization and enhances the overall effectiveness, making the system universally applicable to polyamic acid esters.
Solution Approach 2:
The patent creates a composite additive system combining silane coupling agent with compounds having carboxyl and amino groups. This composite approach allows the silane coupling agent to effectively improve adhesion to inorganic substrates while the accompanying compounds ensure proper reaction kinetics and imidization, thereby maintaining or enhancing the silane coupling agent's effectiveness in polyamic acid ester systems.
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 composition achieves higher imidization degrees for polyamic acid esters at lower temperatures with improved storage stability and enhanced adhesion to inorganic substrates, such as glass and silicon nitride, without compromising the effectiveness of the silane coupling agent.
Implementation Method 1
a specific compound with carboxy and amino/imino groups that deprotect to enhance basicity upon heating
Implementation Method 2
accelerate thermal imidization
Implementation Method 3
The coating film of such a polyimide precursor is imidized by being baked at from 200 to 400° C. to form a polyimide film
Implementation Method 4
a method of using an organic silicon compound called a silane coupling agent
Data Source
AI summary
To provide a polyamic acid ester-containing polyimide precursor composition having a good storage stability, from which a polyimide film having a high imidization degree and excellent adhesion to an inorganic substrate can be obtained.A polyimide precursor composition comprising a polyamic acid ester, a thermal imidization accelerator and a solvent, wherein the thermal imidization accelerator is a compound which has a carboxy group and an amino group or an imino group which is deprotected by heat to show basicity, and which will not accelerate the imidization of the polyamic acid ester before the protecting group leaves, and a polyimide precursor composition containing a silane coupling agent.