Silane-Grafted Polyolefin Wire Coating Reduces Filler Content
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric wire coating materials for automotive applications face challenges in achieving high heat resistance, flexibility, and reduced filler content without using expensive electron beam crosslinking, while maintaining mechanical properties and workability.
Innovation Solution
A composition comprising silane-grafted polyolefin, unmodified polyolefin, modified polyolefin, bromine-based flame retardant, antimony trioxide, crosslinking catalyst, zinc oxide, imidazole-based compound, antioxidant, metal deactivator, and lubricant, which are mixed and subjected to water crosslinking to create a coating material with enhanced gel fraction and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inorganic flame retardant (metal hydroxide) is added to achieve flame retardancy, then flame retardant effect is improved, but mechanical characteristics of coating material decrease
Solution Approach 1:
The patent changes the type of flame retardant from inorganic metal hydroxide to bromine-based organic flame retardant, altering the chemical composition parameters to achieve both flame retardancy and maintained mechanical properties. This parameter change allows effective flame protection without the mechanical degradation caused by inorganic fillers.
Solution Approach 2:
The patent creates a composite coating material system combining silane-grafted polyolefin with bromine-based flame retardant and other additives. This composite approach enables synergistic effects where the organic flame retardant provides fire protection while the silane crosslinked polyolefin matrix maintains mechanical integrity.
2Reliability
If halogen-based organic flame retardant is used to achieve high flame retardant effect, then flame retardancy is improved, but gel fraction (degree of crosslinking) decreases
Solution Approach 1:
The patent applies preliminary silane grafting to the polyolefin before adding the bromine-based flame retardant. This preliminary modification creates reactive sites that enable subsequent crosslinking, ensuring high gel fraction is achieved before flame retardant incorporation, thus preventing the flame retardant from interfering with crosslinking.
Solution Approach 2:
The silane-grafted polyolefin acts as an intermediary between the bromine-based flame retardant and the crosslinking process. The grafted silane groups facilitate crosslinking while the bromine-containing compounds provide flame retardancy, with the modified polyolefin serving as the connecting medium that allows both functions to coexist without compromising gel fraction.
3Ease of manufacture
If non-silane resin is added to create master batch for flame retardant mixing, then ease of manufacture is improved, but degree of crosslinking decreases
Solution Approach 1:
The patent changes the base resin parameter from non-silane resin to silane-grafted polyolefin in the master batch formulation. This parameter change ensures that the resin itself possesses crosslinking capability, so that even when used as a processing aid and carrier for flame retardants, it contributes to the final crosslinked network rather than diluting it.
4Ease of operation
If soft resin is used for coating material to improve workability, then flexibility and workability are improved, but affinity to organic solvent increases causing swelling
Solution Approach 1:
The patent creates a composite system where silane-grafted polyolefin provides the base matrix with good flexibility, while crosslinking agents and specific additives enhance chemical resistance. The composite structure allows the material to maintain softness and workability while developing resistance to organic solvent swelling through the crosslinked network.
Solution Approach 2:
The patent modifies the polyolefin parameters by introducing silane grafts and controlling the density and molecular weight characteristics. These parameter changes enable the resin to achieve an optimal balance between flexibility for workability and crosslinking potential for chemical resistance, reducing affinity to organic solvents while maintaining softness.
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 high heat resistance, flexibility, and reduced filler content, while maintaining mechanical properties and workability, thus meeting automotive standards without the need for expensive electron beam crosslinking equipment.
Implementation Method 1
silane crosslinking, with which crosslinking is possible with inexpensive equipment
Implementation Method 2
Crosslinking of the silane crosslinking material is promoted by moisture in the air during hot molding, and thus is also called 'water crosslinking'
Data Source
AI summary
Provided is an insulated electric wire, a wire harness, and a composition for an electric wire coating material with which the amount of a filler, which is the flame retardant, can be reduced as much as possible without using electron beam crosslinking, the composition having a high heat resistance, a high gel fraction, flexibility, and good workability of assembling a wire harness. An electric wire coating material is made of a composition comprising (A) a silane-grafted polyolefin obtained by grafting a silane coupling agent onto a polyolefin having a density of 0.855 to 0.885 g/cm3, (B) an unmodified polyolefin having a density of 0.890 to 0.955 g/cm3, (C) a modified polyolefin modified by one or more functional groups selected from a carboxylic acid group, an acid anhydride group, an amino group, an acrylic group, a methacrylic group, and an epoxy group, (D) a bromine-based flame retardant and antimony trioxide, (E) a crosslinking catalyst batch, (F) zinc oxide and an imidazole-based compound, or zinc sulfide, (G) an antioxidant, (H) a metal deactivator, and (I) a lubricant.