Insulated Wire Coating for Thick Void-Free Insulation
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Solution Overview
Problem
Existing insulated wires with insulating films made from polyimide or polyamide-imide require multiple thin applications and firing steps to achieve desired thickness, leading to high environmental and cost burdens, and use solvents like NMP and DMAc that are harmful to health and the environment, while also facing challenges in achieving excellent insulation performance with reduced thickness and lower firing temperatures.
Innovation Solution
A compound represented by Formula (1) is used, which does not generate water during sintering, allowing for a single thick application and firing without voids or pinholes, and can be cured at 250°C or lower with a radical polymerization initiator, using solvents like toluene, cyclohexanone, or cyclopentanone for improved workability and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating coating material is thickly applied and fired to form an insulating film of 40-65 μm thickness, then the insulation performance is improved, but voids or pinholes are generated in the insulating film due to water vapor trapped during sintering
Solution Approach 1:
The patent extracts and eliminates the water-generating step from the sintering process by using a sol-free coating material. This prevents water vapor formation during heating, allowing thick coating application without trapped vapor that would create voids or pinholes, thus resolving the contradiction between achieving sufficient thickness for insulation and maintaining film quality.
Solution Approach 2:
The patent changes the chemical composition parameters of the coating material by removing the solvent component entirely and using a sol-free system. This parameter change eliminates water generation during sintering, enabling thick coating application (40-65 μm) to be fired without generating voids or pinholes, thereby resolving the contradiction between insulation performance and film quality.
2Reliability
If an insulating coating material is applied thinly about 1 μm and fired repeatedly 40-65 times to achieve 40-65 μm thickness, then the insulation performance is improved, but the environmental load and manufacturing cost increase significantly
Solution Approach 1:
The patent merges multiple thin coating and firing steps into a single thick coating and firing operation. By using a sol-free coating material that does not generate water vapor, the process combines what would otherwise require 40-65 repetitive cycles into one step, dramatically reducing manufacturing complexity and cost while achieving the same 40-65 μm thickness for insulation performance.
Solution Approach 2:
The patent enables continuous thick coating application and single-step firing to achieve the target thickness, eliminating the need for repeated cyclic operations. This continuous process approach maintains the useful action of building insulating thickness without the interruption and resource consumption of 40-65 repetitive cycles, reducing manufacturing burden while ensuring insulation performance.
3Ease of operation
If NMP or DMAc is used as a solvent for dissolving the precursor of polyimide or polyamide-imide, then the workability is improved, but human health and environment are adversely affected
Solution Approach 1:
The patent extracts and removes the harmful solvent component (NMP or DMAc) from the coating material system entirely, adopting a sol-free approach. This elimination of toxic solvents removes the health and environmental hazards while maintaining workability through the use of reactive precursors that can be applied and cured without conventional solvents, thus resolving the contradiction between ease of operation and harmful factors.
Solution Approach 2:
The patent replaces persistent harmful solvents with a sol-free system that uses reactive precursors forming the insulating film directly upon curing. This substitution eliminates the need for harmful chemical carriers that require special handling and disposal, reducing health and environmental impact while maintaining practical workability through direct coating and curing 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 insulated wire achieves high insulation performance with reduced thickness and lower manufacturing costs, minimizing environmental impact and enabling smaller, lighter electronic devices with enhanced safety by preventing short circuits and electrical leakage.
Implementation Method 1
a compound represented by Formula (1) does not generate water during sintering, and thus can form a cured product having no voids or pinholes caused by water even when the compound is thickly applied and fired
Implementation Method 2
When a radical polymerization initiator is used in combination, the curing initiation temperature of Compound (1) can be lowered (for example, lowered to a temperature of 250° C. or lower)
Implementation Method 3
Toluene, cyclohexanone, or cyclopentanone has a boiling point lower than that of NMP or DMAc and has a large difference from the curing initiation temperature of Compound (1), and thus can be volatilized while suppressing curing of Compound (1)
Data Source
AI summary
Provided is an insulated wire including a coating film excellent in insulation performance even with a small thickness. An insulated wire of the present disclosure includes a conductor wire and an insulating film covering the conductor wire. The insulating film contains a cured product of a compound represented by Formula (1). In Formula (1). R1 and R2 each represent a group represented by Formula (r-1), D1 and D2 each represent a single bond or a linking group. L represents a divalent group having a repeating unit containing a structure represented by Formula (1) and a structure represented by Formula (II),