Silane-Grafted Polyolefin Wire Coating for Heat Resistance
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Solution Overview
Problem
Existing electric wire coating materials for automotive applications face challenges in achieving high heat resistance, mechanical characteristics, and productivity due to the use of electron beam cross-linking, which is costly, and silane cross-linking, which can lead to decreased cross-linking density and die lip build-up, while halogen-based organic flame retardants compromise gelation and wear resistance.
Innovation Solution
A silane-grafted polyolefin-based electric wire coating material composition incorporating a bromine-based flame retardant, antimony trioxide, and a cross-linking catalyst batch, along with zinc oxide and imidazole-based compounds, to enhance heat resistance and prevent die lip build-up, without using metal hydroxides, thereby improving cross-linking density and productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If halogen-based organic flame retardants are used to reduce blend amount and maintain mechanical characteristics, then flame retarding effect is improved, but gelation rate and wear resistance decrease
Solution Approach 1:
The patent changes the chemical composition parameters by using bromine-based flame retardant in combination with specific cross-linking agents and catalysts. This parameter change allows achieving flame retardancy while maintaining wear resistance through optimized chemical interactions in the coating material system.
Solution Approach 2:
The patent creates a composite material system combining polyolefin resin, silane cross-linking agent, bromine-based flame retardant, and metal deactivator. This composite approach allows each component to contribute its strengths: the flame retardant provides fire resistance, the silane provides cross-linking for mechanical strength, and the metal deactivator protects against degradation, achieving overall improvement in both flame retardancy and wear resistance.
2Ease of manufacture
If silane cross-linking is used to reduce equipment cost compared to electron beam cross-linking, then manufacturing cost is improved, but cross-linking density decreases and die lip build-up occurs
Solution Approach 1:
The patent introduces a metal deactivator as an intermediary substance that mediates between the silane cross-linking agent and metal ions in the system. This intermediary prevents unwanted side reactions that would otherwise reduce cross-linking density and cause die lip build-up, allowing silane cross-linking to proceed effectively at lower cost while maintaining high cross-linking density.
Solution Approach 2:
The patent optimizes the chemical parameters by selecting specific combinations of silane cross-linking agents, catalysts, and metal deactivators. This parameter optimization ensures that cross-linking proceeds with high density and uniformity, preventing die lip build-up while maintaining the cost advantage of silane cross-linking over electron beam methods.
3Temperature
If cross-linking density is increased to improve heat resistance and mechanical characteristics, then heat resistance is improved, but die lip build-up and abnormal substance generation increase
Solution Approach 1:
The metal deactivator serves as a protective intermediary that prevents excessive cross-linking reactions and formation of abnormal substances. By controlling the interaction between cross-linking agents and metal ions, it enables achieving high heat resistance through proper cross-linking density while preventing die lip build-up that would reduce productivity.
Solution Approach 2:
The patent carefully controls the parameters of cross-linking by selecting appropriate catalysts and cross-linking agents in specific combinations. This parameter control allows achieving optimal cross-linking density that provides high heat resistance while avoiding excessive cross-linking that would cause die lip build-up and abnormal substance generation, thus maintaining productivity.
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 effectively enhances heat resistance and mechanical characteristics while maintaining productivity by improving cross-linking density and preventing die lip build-up, ensuring compliance with automotive standards without compromising chemical resistance.
Implementation Method 1
silane cross-linking that can be performed with inexpensive equipment has been attracting attention
Implementation Method 2
a gelation rate, which is an index of the degree of cross-linking
Implementation Method 3
a bromine-based flame retardant and antimony trioxide (D)
Implementation Method 4
a cross-linking catalyst batch (E) obtained by dispersing a cross-linking catalyst in a binder resin
Implementation Method 5
zinc oxide and imidazole-based compounds, to enhance heat resistance
Data Source
AI summary
A flame-retardant electric wire coating material composition that can improve heat resistance without using electron beam cross-linking, has no risk of reducing the mechanical characteristics and chemical resistance due to no metal hydroxides being added thereto as flame retardants, and can suppress the formation of die lip build-up and the like during manufacturing to achieve favorable productivity, and an insulated electric wire and a wire harness. The electric wire coating material composition may include:a silane-grafted polyolefin (A);an unmodified polyolefin (B);a modified polyolefin (C);a bromine-based flame retardant and antimony trioxide (D);a cross-linking catalyst batch (E);zinc oxide and an imidazole-based compound modified with a mercapto group, or zinc sulfide (F);an antioxidant, a metal deactivator, and a lubricant (G);silicone oil (H); andno metal hydroxides.