EVA Insulated Wire Coating for Heat Resistance and Flexibility
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Solution Overview
Problem
Insulated wires used in automobiles require improved flexibility, heat resistance, crosslinkability, and passing properties under high-temperature environments to meet stringent standards and ensure effective terminal sealing and assembly efficiency.
Innovation Solution
A resin composition comprising an ethylene-vinyl acetate copolymer resin blended with specific amounts of imidazole, phenol, thioether compounds as antioxidants, and bromine and antimony compounds as flame retardants, along with optional components like maleic acid-modified polyethylene resin, is used to form an insulating film, enhancing heat resistance and passing properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional resin compositions are used to achieve flame retardancy and heat resistance, then these properties are improved, but flexibility and passing properties under high-temperature environments deteriorate
Solution Approach 1:
The patent optimizes the content ranges of specific additives (benzimidazole-based antioxidant: 5-15 parts, phenol-based antioxidant: 2-6 parts, thioether-based antioxidant: 1-3 parts per 100 parts of ethylene-vinyl acetate copolymer) to achieve a balance between heat resistance and flexibility. This parameter optimization allows the resin composition to maintain passing properties at high temperatures while achieving the required heat resistance level.
Solution Approach 2:
The patent uses a composite resin composition based on ethylene-vinyl acetate copolymer combined with multiple types of antioxidants (benzimidazole-based, phenol-based, and thioether-based) and flame retardants. This composite approach creates synergistic effects that improve both heat resistance and flexibility simultaneously, resolving the contradiction between these properties.
2Reliability
If crosslinking is enhanced to improve terminal sealing characteristics, then sealing performance is improved, but assembly efficiency and passing properties deteriorate
Solution Approach 1:
The patent optimizes the crosslinking degree by controlling the content of crosslinking agents and curing conditions to achieve a gel fraction of 30-80%. This optimized crosslinking level provides sufficient terminal sealing characteristics while maintaining the flexibility and passing properties needed for efficient assembly operations.
Solution Approach 2:
The patent applies partial crosslinking rather than complete crosslinking, achieving a gel fraction in the range of 30-80% rather than 100%. This partial action approach provides adequate terminal sealing performance while preserving enough flexibility for assembly efficiency, avoiding the excessive crosslinking that would cause brittleness and poor passing properties.
3Duration of action of stationary object
If resin composition is optimized for heat resistance, then heat-resistant life is improved, but processing adhesion and flexibility worsen
Solution Approach 1:
The patent optimizes the content of vinyl acetate groups in the ethylene-vinyl acetate copolymer (10-40 mass%) and the amounts of specific antioxidants to achieve a balance between heat-resistant life and processing adhesion. This parameter optimization ensures good adhesion to conductors during processing while maintaining long-term heat resistance.
Solution Approach 2:
The patent combines ethylene-vinyl acetate copolymer with multiple types of antioxidants and flame retardants to create a composite material that maintains processing adhesion properties while achieving extended heat-resistant life. The composite formulation ensures both manufacturing ease and long-term durability.
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 resulting insulated wires exhibit excellent heat resistance, crosslinkability, and improved passing properties, meeting high-temperature performance requirements and ensuring efficient assembly in vehicle wire harnesses.
Implementation Method 1
by crosslinking the resin composition, an insulated wire can be obtained that exhibits desired excellent characteristics
Implementation Method 2
irradiating the resin composition layer with an electron beam of 80 to 250 kGy
Data Source
AI summary
A resin composition including an ethylene-vinyl acetate copolymer resin as a resin component, an imidazole compound, a phenol compound, and a thioether compound as an antioxidant, and a bromine compound and an antimony compound as a flame retardant. The resin composition has a content of the imidazole compound of 14 to 24 parts by mass, a content of the phenol compound of 1.0 to 2.0 parts by mass, a content of the thioether compound of 0.3 to 0.9 parts by mass, a content of the bromine compound of 15 to 30 parts by mass, and a content of the antimony compound of 5 to 15 parts by mass with respect to 100 parts by mass of a total content of the resin component in the resin composition.