Non-halogen Flame-Retardant Insulated Wire with Dual-Layer Structure
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Solution Overview
Problem
Existing non-halogen flame-retardant insulated wires face challenges in meeting the requirements for flame retardance, mechanical properties, oil resistance, fuel resistance, and cold resistance, with increased metal hydroxide addition degrading mechanical properties and not fully satisfying the latest resistance levels.
Innovation Solution
A non-halogen flame-retardant insulated wire design featuring a two-layered insulating coating with an inner layer composed of 50-95 parts polyethylene and 5-50 parts ethylene copolymer, and an outer layer comprising 60-95 parts ethylene-vinyl acetate copolymer with 60% vinyl acetate and 5-40 parts maleic acid-modified ethylene-α-olefin copolymer, crosslinked with 80-200 parts metal hydroxide, enhancing mechanical and resistance properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the addition amount of metal hydroxide is increased to obtain high flame retardance, then flame retardance is improved, but mechanical properties (e.g., elongation of the insulating coating) are degraded
Solution Approach 1:
The insulating coating is divided into two layers: an inner layer containing metal hydroxide for flame retardance and an outer layer without metal hydroxide for mechanical properties. This segmentation allows each layer to optimize its function independently, resolving the contradiction between flame retardance and mechanical strength.
Solution Approach 2:
Different regions of the insulating coating are assigned different compositions and properties. The inner layer has high metal hydroxide content (80-200 parts by weight per 100 parts base polymer) for flame retardance, while the outer layer has no metal hydroxide for mechanical strength, creating local quality differentiation.
2Reliability
If existing resin compositions are used to meet flame retardance requirements, then flame retardance is achieved, but the latest required levels of oil resistance, fuel resistance, and cold resistance are not satisfied
Solution Approach 1:
The invention changes the chemical composition parameters of the resin system. The outer layer uses ethylene-vinyl acetate copolymer with 60-95 parts by weight and vinyl acetate content of 40-65% by weight, which provides superior oil resistance, fuel resistance, and cold resistance compared to conventional compositions.
Solution Approach 2:
The insulating coating uses a composite structure with two different resin systems: inner layer with polyethylene and metal hydroxide for flame retardance, and outer layer with ethylene-vinyl acetate copolymer for multi-resistance properties, achieving comprehensive performance.
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 provides improved tensile strength, elongation, oil resistance, fuel resistance, cold resistance, and flame retardance while maintaining insulating properties, satisfying all required properties for insulated wires without using halogen compounds.
Implementation Method 1
At least the outer layer resin composition is crosslinked
Implementation Method 2
a metal hydroxide (e.g., magnesium hydroxide, aluminum hydroxide)
Implementation Method 3
80 to 200 parts by weight of a metal hydroxide
Data Source
AI summary
A non-halogen flame-retardant insulated wire includes a conductor and an insulating coating layer including an inner layer and an outer layer. The inner layer includes a composition in which 50 to 95 parts by weight of a polyethylene with a density of 0.930 g/cm3 or more and 5 to 50 parts by weight of an ethylene copolymer are mixed. The outer layer has a composition including a base polymer in which 60 to 95 parts by weight of an ethylene-vinyl acetate copolymer containing 60% by weight or more of vinyl acetate and 5 to 40 parts by weight of a maleic acid-modified ethylene-α-olefin copolymer are mixed, and including 80 to 200 parts by weight of a metal hydroxide. The outer layer resin composition is crosslinked.