Crosslinking Precursors in Coating Solutions for Solvent-Resistant Films

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Solution Overview

Problem

Soluble polymers with imide groups lack the solvent resistance required for electronic component manufacturing, leading to degradation during fabrication.

Innovation Solution

A coating solution comprising a soluble polymer with an imide group and a crosslinking precursor, where the precursor includes a first amine group that is either reactive or passivated, and additional amine groups that are passivated to form at least two reactive amines upon activation by an external stimulus, allowing for crosslinking after film formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If soluble polymers with imide groups are used to form polymer films, then the film-forming temperature is lowered and processing is simplified, but the solvent resistance is insufficient leading to degradation during fabrication

Engineering Contradiction:
Improvefilm-forming temperatureVSAvoidsolvent resistance
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent applies preliminary action by incorporating a crosslinking precursor into the coating solution before film formation. The precursor remains dormant during casting and drying, then activates later to crosslink the polymer film. This allows the film to be formed at low temperatures using soluble polymers, then subsequently strengthened through crosslinking to achieve the required solvent resistance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses parameter changes by transforming the chemical state of the crosslinking precursor from passivated to reactive through external stimuli (heat, light, or chemical treatment). This parameter change enables the polymer film to transition from a soluble, low-crosslinking state during processing to an insoluble, highly crosslinked state for final application, thereby achieving both low processing temperature and high solvent resistance.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If crosslinking is performed immediately in the coating solution, then solvent resistance is improved, but the polymer film cannot be properly formed and processed

Engineering Contradiction:
Improvesolvent resistanceVSAvoidfilm formation capability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by preparing the coating solution with a crosslinking precursor that is passivated during film formation. The polymer chains are allowed to form and process normally in the soluble state first, then crosslinking is activated afterward. This sequence ensures proper film formation is achieved before crosslinking enhances solvent resistance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses an intermediary approach by introducing a crosslinking precursor that acts as a dormant crosslinking agent during film formation. This precursor does not interfere with the initial polymer film formation but becomes active later to provide crosslinking. The intermediary enables both film formation and crosslinking to occur in sequence without mutual interference.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If multiple amine groups are made reactive in the crosslinking precursor, then crosslinking efficiency is improved, but unwanted side reactions during film formation may occur

Engineering Contradiction:
Improvecrosslinking efficiencyVSAvoidfilm formation stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies the taking out principle by separating the crosslinking function from the film formation process. The crosslinking precursor contains multiple amine groups but they are passivated (taken out of service) during film formation. Only after film formation is complete are the amine groups activated to perform crosslinking. This separation prevents side reactions during film formation while maintaining high crosslinking efficiency afterward.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses preliminary anti-action by passivating the amine groups in the crosslinking precursor during film formation. This passivation prevents unwanted side reactions between the amine groups and other components during film formation. The anti-action (passivation) is applied in advance, then removed later to allow the desired crosslinking reaction to proceed efficiently.

Inventive Principle:
Principle #9Preliminary anti-action

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 process results in polymer films with excellent solvent resistance and improved mechanical properties, achieved by activating the crosslinking precursor using heat, light, or a chemical species to form reactive amines, enabling crosslinking and enhancing film durability.

Implementation Method 1

The crosslinking precursor can be chemically converted, thermally converted, photo-converted or dissociated to form at least two reactive amines

Methodology Applied
Scientific EffectPhotodissociation: Photodissociation

Implementation Method 2

The crosslinking precursor can be chemically converted, thermally converted, photo-converted or dissociated to form at least two reactive amines

Methodology Applied
Scientific EffectThermolysis: Thermolysis

Implementation Method 3

activate the crosslinking precursor to form at least two reactive amines and crosslink the polymer

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Data Source

PatentUS12404421B2Coating solutions and crosslinked polymer films
Publication Date: 2025.09.02 DUPONT ELECTRONICS INC

AI summary

In a first aspect, a coating solution includes a soluble polymer and a crosslinking precursor. The soluble polymer includes an imide group. The crosslinking precursor includes a first amine group that is either reactive or passivated towards crosslinking and one or more additional amine groups, wherein the one or more additional amine groups has been passivated towards crosslinking such that the crosslinking precursor can be chemically converted, thermally converted, photo-converted or dissociated to form at least two reactive amines. In a second aspect, a process for forming a polymer film includes: (a) casting a coating solution, (b) activating the crosslinking precursor using an external stimulus to form at least two reactive amines and crosslink the polymer, and (c) drying the polymer film. The coating solution includes a soluble polymer, including an imide group, and a crosslinking precursor.