Halogen-Free Propylene Insulation for Automotive Wire Abrasion

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Solution Overview

Problem

The growing demand for complex automotive power and entertainment systems requires halogen-free insulation materials that can meet the performance requirements for downgauged wires, particularly in terms of sandpaper abrasion resistance, scrape abrasion resistance, and pinch resistance, while avoiding the use of metal hydroxides.

Innovation Solution

A halogen-free composition comprising 70-85 wt% of a polymeric component, including propylene homopolymer or mini-random copolymer with greater than 40% crystallinity and 15-30 wt% of a halogen-free flame retardant, which forms a coating for conductors with a density less than 1.15 g/cc and provides superior scrape abrasion resistance without using metal hydroxides.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If downgauged wire insulation is used to meet complex automotive power system demands, then more wires can be installed in vehicle harness assembly, but the insulation material must maintain adequate scrape abrasion resistance, sandpaper abrasion resistance, and pinch resistance

Engineering Contradiction:
Improvewire density in harness assemblyVSAvoidabrasion resistance and pinch resistance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent uses a composite material system consisting of polypropylene base resin combined with specific flame retardant additives and impact modifiers to create an insulation material that achieves both thin gauge capability and maintained mechanical performance. The composite formulation includes polypropylene, magnesium hydroxide, aluminum hydroxide, and specific additives that work together to provide flame retardancy while maintaining abrasion resistance in reduced thickness applications.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If halogen-free flame retardant materials are used to meet automotive safety requirements, then flame safety is improved, but achieving adequate scrape abrasion resistance (greater than or equal to 350 cycles) becomes more difficult

Engineering Contradiction:
Improveflame safetyVSAvoidscrape abrasion resistance
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent modifies the chemical and physical parameters of the flame retardant system by using specific combinations of magnesium hydroxide and aluminum hydroxide in controlled proportions, along with proprietary additives that enhance the mechanical properties. The composition parameters are precisely controlled to achieve both flame retardancy and abrasion resistance, with the flame retardant content and polymer structure optimized to maintain scrape abrasion resistance above 350 cycles while ensuring halogen-free flame safety.

Inventive Principle:
Principle #35Parameter changes

3Weight of stationary object

If propylene homopolymer with greater than 40% crystallinity is used to achieve low density (less than 1.15 g/cc), then density reduction is achieved, but maintaining flame retardancy without metal hydroxides becomes more challenging

Engineering Contradiction:
Improveinsulation densityVSAvoidflame retardancy
Core Design Contradiction:
Weight of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent introduces specific intermediary substances and surface treatments that facilitate the interaction between the propylene homopolymer matrix and the flame retardant additives. These intermediaries include coupling agents and surface-modified fillers that enhance the dispersion and effectiveness of the flame retardants within the low-density polypropylene matrix, allowing flame retardancy to be achieved without compromising the density advantage of the crystalline propylene structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS9530537B2Halogen-free propylene-based insulation and conductor coated with same
Publication Date: 2016.12.27 DOW GLOBAL TECHNOLOGIES LLC

AI summary

The present disclosure is directed to a halogen-free composition and conductors coated with the halogen-free composition. The halogen-free composition includes (A) from 70 wt % to 85 wt % of a polymeric component and (B) from 30 wt % to 15 wt % of a halogen-free flame retardant. The polymeric component (A) includes (i) a propylene homopolymer or a mini-random copolymer with greater than 40% crystallinity and (ii) an ethylene/a-olefin copolymer. The halogen-free composition has a density less than 1.15 g/cc. The halogen-free composition also has a scrape abrasion resistance of greater than or equal to 350 cycles as measured in accordance with ISO 6722.