Polypropylene Wire Protective Member for High Voltage Harnesses
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Solution Overview
Problem
Current wire protective members for high voltage wires in vehicles face challenges with heat resistance, flame retardancy, and resistance against calcium chloride and braided wires, particularly when using polyolefin-based corrugate tubes, which deteriorate upon contact with braided copper wires.
Innovation Solution
A composition for a wire protective member comprising polypropylene with specific properties, combined with bromine-based flame retardants, antimony trioxide, phenol-based antioxidants, and metal deactivators, providing enhanced heat resistance, flame retardancy, and resistance against calcium chloride and braided wires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If polyolefin is used for wire protective member, then resistance against calcium chloride is improved, but heat resistance deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters by using polypropylene with specific properties (melt flow rate of 0.5 to 5 g/10 min, melting point of 150°C or more, tensile strength of 20 to 35 MPa, Charpy impact strength of 10 kJ/m2 or more) instead of conventional polyolefin, thereby achieving both heat resistance and resistance against calcium chloride simultaneously
Solution Approach 2:
The patent creates a composite material system by combining polypropylene with flame retardants (bromine-based flame retardant and antimony trioxide), antioxidants (phenol-based antioxidant), and metal deactivators, achieving multiple properties including heat resistance, flame retardancy, and resistance against calcium chloride and braided wires in a single composition
2Temperature
If polyamide 6 is used for wire protective member, then heat resistance is improved, but resistance against calcium chloride deteriorates
Solution Approach 1:
The patent changes the base polymer from polyamide 6 to polypropylene with specific parameters (melt flow rate of 0.5 to 5 g/10 min, melting point of 150°C or more), thereby achieving both heat resistance comparable to polyamide 6 and resistance against calcium chloride that polyamide 6 lacks
3Reliability
If braided wire is added to improve shielding ability, then shielding ability is improved, but heat aging resistance of polyolefin deteriorates
Solution Approach 1:
The patent introduces metal deactivators and phenol-based antioxidants as intermediary substances that prevent direct harmful interaction between the polypropylene and the braided copper wire, thereby maintaining heat aging resistance while allowing the braided wire to provide shielding ability
Solution Approach 2:
The patent creates a composite material system that includes metal deactivators and antioxidants combined with polypropylene, which together provide both the shielding capability (when used with braided wire) and the heat aging resistance that pure polyolefin lacks
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 achieves a wire protective member with improved heat resistance, flame retardancy, and resistance against calcium chloride and braided wires, suitable for high voltage wire applications in vehicles, maintaining performance even when in contact with copper braids.
Implementation Method 1
a phenol-based antioxidant as a heat resistance life improving agent
Implementation Method 2
a bromine-based flame retardant and an antimony trioxide as a flame retarder
Implementation Method 3
a metal deactivator
Data Source
AI summary
A composition for a wire protective member with heat resistance, flame retardancy, and resistance against both a calcium chloride and a braided wire; a wire protective member and a wire harness using the composition. The composition for a wire protective member is produced by including a polypropylene having a propylene monomer constituting 50 to 95 percent by mass of monomers forming a polymer, a melt flow rate of 0.5 to 5 g/10 min, and a melting point of 150 degrees C. or more; a bromine-based flame retardant and an antimony trioxide as a flame retarder; a phenol-based antioxidant as a heat resistance life improving agent; and a metal deactivator, wherein the propylene has a tensile strength of 20 to 35 MPa and a Charpy impact strength of 10 kJ/m2 or more at 23 degrees C.