Silane-Crosslinked Polyolefin Flame-Retardant Composition

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Solution Overview

Problem

Conventional insulated wires have a maximum allowable temperature limit of 120° C, which is insufficient for high-temperature environments like automobile engine rooms, necessitating the development of materials with enhanced heat resistance up to 150° C.

Innovation Solution

A flame-retardant composition comprising silane-crosslinked polyolefin, magnesium hydroxide or aluminum hydroxide, phenolic antioxidant, sulfurous antioxidant (benzimidazole compound), zinc oxide, and copper inhibitor, with specific mass ratios, is used to create an insulated wire with improved heat resistance, flexibility, and oil resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional crosslinked polyvinylchloride or crosslinked polyethylene is used as covering material, then heat resistance is improved with allowable temperature limit of 120°C, but the material cannot achieve the required 150°C heat resistance for modern automobile engine rooms

Engineering Contradiction:
Improveallowable temperature limitVSAvoidheat resistance performance
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters by incorporating silane-crosslinked polyolefin as the base resin and adding specific combinations of antioxidants (phenolic and sulfurous types), copper inhibitors, and zinc oxide. This compositional parameter change enables the material to withstand temperatures up to 150°C, resolving the contradiction between conventional material limitations and required heat resistance performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite flame-retardant composition by combining silane-crosslinked polyolefin with multiple functional additives including magnesium hydroxide or aluminum hydroxide (28-190 parts by mass), phenolic antioxidants (0.5-9.5 parts by mass), sulfurous antioxidants (0.5-9.5 parts by mass), zinc oxide (0.5-9.5 parts by mass), and copper inhibitors (0.1-4.7 parts by mass). This composite approach achieves both the required 150°C heat resistance and flame retardancy that conventional single-material solutions cannot provide.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If halogen-containing materials like polyvinyl chloride are used to achieve flame retardancy, then flame resistance is improved, but environmental harm increases due to halogen reduction requirements

Engineering Contradiction:
Improveflame resistanceVSAvoidenvironmental harm from halogen
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent replaces harmful halogen-containing materials with non-halogenated silane-crosslinked polyolefin combined with metal hydroxides (magnesium hydroxide or aluminum hydroxide at 28-190 parts by mass). This substitution eliminates environmental harm from halogen while maintaining flame resistance through the decomposition endothermic reaction of metal hydroxides and the formation of protective char layers, converting the limitation into a beneficial environmental solution.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the chemical composition from halogen-based to non-halogenated silane-crosslinked polyolefin system. This parameter change in chemical composition achieves flame retardancy through alternative mechanisms (metal hydroxide decomposition, carbon char formation) without the environmental harm associated with halogen release, resolving the contradiction between flame resistance and environmental compatibility.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If polyolefin content is increased to maintain flexibility and processability, then ease of operation is improved, but flame retardancy and heat resistance may be compromised

Engineering Contradiction:
Improveflexibility and processabilityVSAvoidflame retardancy
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent creates a balanced composite system where silane-crosslinked polyolefin serves as the continuous matrix providing flexibility and processability, while metal hydroxides (28-190 parts by mass), zinc oxide (0.5-9.5 parts by mass), and antioxidant packages provide flame retardancy and heat resistance. This composite structure allows high polyolefin content for ease of operation while the dispersed flame-retardant particles maintain safety performance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent distributes flame-retardant additives (metal hydroxides, zinc oxide, antioxidants) as discrete particles within the polyolefin matrix, creating local flame-retardant zones that do not compromise the overall flexibility and processability of the material. This local quality approach allows the bulk material to remain processable while specific regions provide flame protection.

Inventive Principle:
Principle #3Local quality

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 composition achieves heat resistance exceeding 150° C, enabling the insulated wire to perform effectively in high-temperature environments while maintaining flexibility and resistance to gasoline exposure.

Implementation Method 1

silane-crosslinked polyolefin

Methodology Applied
Scientific EffectSilane crosslinking: Chemical Bonding

Implementation Method 2

a metal hydroxide such as a magnesium hydroxide is often added to the material as a flame retardant

Methodology Applied
Scientific EffectDecomposition reaction: Decomposition (biological)

Implementation Method 3

a phenolic antioxidant, the phenolic antioxidant content being 0.5 to 9.5 parts by mass with respect to 100 parts by mass of the polymer component, a sulfurous antioxidant that is a benzimidazole compound

Methodology Applied
Scientific EffectAntioxidation: Oxidation

Implementation Method 4

a zinc oxide, the zinc oxide content being 0.5 to 9.5 parts by mass with respect to 100 parts by mass of the polymer component

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 5

a copper inhibitor, the copper inhibitor content being 0.1 to 4.7 parts by mass with respect to 100 parts by mass of the polymer component

Methodology Applied
Scientific EffectCorrosion inhibition: Oxidation

Data Source

PatentUS8895857B2Flame-retardant composition and insulated wire, and method for producing flame-retardant composition
Publication Date: 2014.11.25 AUTONETWORKS TECH LTD

AI summary

A flame-retardant composition that is more excellent in heat resistance than a conventional flame-retardant composition. The flame-retardant composition contains silane-crosslinked polyolefin, polyolefin, a metallic hydrate, a phenolic antioxidant, a sulfurous antioxidant, a metallic oxide, and a copper inhibitor. The sulfurous antioxidant is preferably a benzimidazole compound, and the metallic oxide is preferably a zinc oxide. The silane-crosslinked polyolefin is preferably polyethylene having a density of 0.880 to 0.910 g/cm3 that is silane-crosslinked. The polyolefin is preferably polyethylene having a density of 0.880 to 0.910 g/cm3, or an olefin elastomer having a melting point of 140° C. or more.