Crosslinked Insulating Layer for Flame-Retardant Electric Wire
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Solution Overview
Problem
Conventional non-halogen flame-retardant electric wires and cables face issues with abrasion resistance, terminal processability, and handling in high-temperature environments due to the use of soft polyolefins like EVA, which are prone to deformation and damage, and struggle with clean cuts during terminal stripping, leading to sparks and fusion in high-temperature conditions.
Innovation Solution
A non-halogen flame-retardant insulated electric wire and cable design featuring a crosslinked insulating layer with a tensile elastic modulus of 500 MPa or more, elongation at break of 120% or less, and a storage elastic modulus of 3×106 Pa or more at 125°C, utilizing a coating material with magnesium hydroxide or aluminum hydroxide and a polyolefin with a melting point of 120°C or higher, enhancing abrasion resistance and handling ease.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If soft polyolefin (EVA) is used as base polymer to achieve non-halogen flame retardancy, then flame retardancy is improved, but abrasion resistance and strength deteriorate
Solution Approach 1:
The patent uses a composite material system combining polyolefin base polymer with specific additives (silane coupling agent, crosslinking agent, flame retardant) to create a crosslinked coating material that maintains flame retardancy while achieving high strength and abrasion resistance through crosslinked network structure
Solution Approach 2:
The patent changes the physical and chemical parameters of the coating material by controlling the crosslinking degree (measured by gel fraction), tensile elastic modulus (500-2000 MPa), and elongation at break (100-150%), transforming the material from soft and weak to strong and durable while maintaining flame retardancy
2Reliability
If soft polyolefin coating material is used, then non-halogen flame retardancy is achieved, but terminal processability deteriorates due to stretching and inability to obtain clean cut
Solution Approach 1:
The patent modifies the mechanical parameters of the coating material by implementing crosslinking, which increases tensile elastic modulus to 500-2000 MPa and optimizes elongation at break to 100-150%, enabling the material to be cleanly stripped without stretching while maintaining flame retardant properties
3Ease of manufacture
If conventional coating material with melting point below 120°C is used, then processing is easier, but handling ease in high-temperature environment deteriorates due to fusion and deformation
Solution Approach 1:
The patent elevates the melting point parameter of the coating material to 120°C or higher through crosslinking and material composition optimization, enabling the wire to maintain structural integrity and resist fusion in high-temperature environments (up to 150°C) while remaining processable
Solution Approach 2:
The patent creates different functional zones within the coating material: the crosslinked network structure provides high-temperature stability and resistance to fusion, while the polyolefin base polymer maintains processability and flexibility at lower temperatures
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 excellent abrasion resistance, improved terminal processability, and ease of handling in high-temperature environments, while maintaining high flame retardancy and preventing fusion and deformation, thus addressing the limitations of existing technologies.
Implementation Method 1
the insulating layer has a tensile elastic modulus of 500 MPa or more and an elongation at break of 120% or less
Implementation Method 2
a crosslinked single-layer or multilayer insulating layer on an outer periphery of the conductor
Implementation Method 3
the insulating layer has an outermost layer formed of a coating material that contains magnesium hydroxide and/or aluminum hydroxide
Data Source
AI summary
A non-halogen flame-retardant insulated electric wire includes a conductor and a crosslinked single-layer or a multilayer insulating layer on an outer periphery of the conductor. The insulating layer has a tensile elastic modulus of 500 MPa or more and an elongation at break of 120% or less in a tensile test performed at a displacement rate of 200 mm/min, and has a storage elastic modulus at 125° C. of 3×106 Pa or more in a dynamic viscoelasticity test.