Flexible Cable Double-Layer Polypropylene Sheath
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Solution Overview
Problem
Flexible cables with outer sheaths made of polyurethane resin, silicone rubber, or styrene-based compounds are unsmooth to handle manually due to stickiness, while those made of plasticized polyvinyl chloride have low thermal resistance and are prone to damage during autoclave sterilization.
Innovation Solution
A flexible cable with a double-layer outer sheath comprising an inner layer of elastomer-containing polypropylene resin and an outer layer of polypropylene resin, featuring a thin outer layer with numerous cracks for reduced friction and high thermal resistance, which is fusion-bonded with the inner layer for durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the outer sheath is made of polyurethane resin, silicone rubber, or styrene-based rubber compound, then the cable maintains high flexibility and thermal resistance, but the surface becomes sticky causing unsmooth manual handling
Solution Approach 1:
The outer sheath is divided into two distinct layers: an inner layer made of elastomer containing polypropylene resin (providing flexibility and thermal resistance) and an outer layer made of polypropylene resin (providing non-sticky surface). This segmentation allows each layer to perform its specific function independently, resolving the contradiction between flexibility and surface stickiness.
Solution Approach 2:
The outer sheath uses a composite structure combining elastomer-containing polypropylene resin in the inner layer with pure polypropylene resin in the outer layer. This composite material approach integrates the advantages of both materials: the elastomer provides flexibility and heat resistance while the polypropylene outer layer provides a non-sticky surface for smooth handling.
2Ease of operation
If the outer sheath is made of plasticized polyvinyl chloride to eliminate surface stickiness, then manual handling becomes smooth, but thermal resistance decreases causing damage during autoclave sterilization
Solution Approach 1:
The outer sheath is segmented into two layers where the inner layer (elastomer-containing polypropylene resin) provides the necessary thermal resistance for autoclave sterilization, while the outer layer (polypropylene resin) provides the non-sticky surface. This segmentation allows the cable to withstand sterilization temperatures without becoming sticky or damaged.
Solution Approach 2:
The composite structure combines polypropylene resin (high thermal resistance, non-sticky) with elastomer (flexibility, thermal resistance). This composite material achieves both smooth handling and autoclave resistance, eliminating the need for plasticized polyvinyl chloride which lacks sufficient thermal stability.
3Ease of operation
If a thin outer layer is added to reduce surface friction, then manual handling becomes smooth, but the layer may become too thin causing structural weakness
Solution Approach 1:
The thickness of the outer polypropylene resin layer is optimized to a specific range (5-50 μm, preferably 10-30 μm). This parameter optimization ensures the layer is thin enough to provide smooth handling through surface cracks but thick enough to maintain structural integrity and protect the inner layer during autoclave sterilization.
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 flexible cable provides a smooth handling experience and enhanced resistance to autoclave sterilization without stickiness or damage, ensuring both flexibility and thermal stability.
Implementation Method 1
the outer layer has a large number of cracks in a surface of the outer layer
Implementation Method 2
the outer layer is fusion-bonded with the inner layer
Implementation Method 3
the outer layer made of polypropylene resin... having high thermal resistance
Data Source
AI summary
A flexible cable includes an outer sheath at an outermost portion. The outer sheath includes an inner layer made of an elastomer containing polypropylene resin, and an outer layer surrounding the inner layer and made of polypropylene resin.