Multi-Layer Cable Covering with Halogen-Free Flame Retardant

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Solution Overview

Problem

Halogen-free flame retardant polymer systems for cable coverings often exhibit poor surface quality, chemical resistance, and weathering resistance, making them unsuitable for consumer electronics applications due to high amounts of non-halogen flame retardants, which can cause rough surfaces, staining, and undesirable color changes.

Innovation Solution

A multi-layer cable covering with an inner sheath layer comprising halogen-free flame retardants and an outer sheath layer made of styrenic block copolymers essentially free of flame retardants, achieving desirable chemical and weathering resistance while passing the VW-1 flame test according to UL 1581, section 1080.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If halogen-free flame retardant polymer systems are used to achieve flame retardant performance, then flame retardance is improved, but surface quality deteriorates (rough or non-smooth surfaces)

Engineering Contradiction:

Improveflame retardanceVSAvoidsurface quality

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The cable covering is divided into two distinct sheath layers: an inner sheath layer containing halogen-free flame retardant polymer and flame retardant materials to achieve flame retardant performance, and an outer sheath layer made of smooth polymer material to provide excellent surface quality. This segmentation allows each layer to optimize its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the cable covering are assigned different material properties: the inner sheath layer is designed with flame retardant characteristics while the outer sheath layer is designed with smooth surface qualities. This local differentiation resolves the contradiction by allowing flame retardant materials to be present only where necessary for safety, while the outer surface maintains aesthetic and tactile quality.

Inventive Principle:

Principle #3Local quality

2Reliability

If high amounts of non-halogen flame retardants are used to meet flame retardant standards, then flame retardance is improved, but chemical resistance deteriorates

Engineering Contradiction:

Improveflame retardanceVSAvoidchemical resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The outer sheath layer acts as an intermediary protective barrier between the environment and the inner sheath layer containing flame retardant materials. This outer layer provides chemical resistance and protects the inner layer from chemical degradation, while the inner layer maintains flame retardant properties.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If halogen-free flame retardant polymer systems are used to achieve flame retardant performance, then flame retardance is improved, but weathering resistance deteriorates

Engineering Contradiction:

Improveflame retardanceVSAvoidweathering resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inventive Principle:

Principle #24Intermediary (Mediator)

4Reliability

If halogen-free flame retardant polymer systems are used to achieve flame retardant performance, then flame retardance is improved, but surface aesthetics deteriorate (staining by skin oil and household products)

Engineering Contradiction:

Improveflame retardanceVSAvoidsurface aesthetics

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS10839979B2Cable with flame retardant multi-layer covering

Publication Date: 2020.11.17 TEKNOR APEX COMPANY

AI summary

A cable comprising a covering having two or more different sheath layers, with the covering providing superior chemical and weathering resistance, and excellent surface feel. In a preferred embodiment, the outermost sheath layer of the covering is a thermoplastic elastomer essentially free of a flame retardant material, yet the covering achieves desirable flame retardant performance due to the presence of an inner sheath layer comprising a thermoplastic elastomer and a flame retardant, preferably halogen-free flame retardant. The outermost sheath layer also exhibits sought-after surface qualities. Methods for producing the coverings and flame retardant cables are disclosed.