Recycled Cable Coating Composition for Strength and Surface Quality
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Solution Overview
Problem
Recycled polymer materials typically provide cable coating layers with poor mechanical properties, surface appearance, and can have a sticky surface, which are exacerbated when mixed with virgin polymers, reducing environmental and economic benefits.
Innovation Solution
A cable coating layer composition comprising 70-95% recycled linear low density polyethylene (r-LLDPE) and 5-30% ethylene-vinyl acetate copolymer (EVA) provides improved mechanical properties and surface appearance, with optional additives like detackifiers and carbon black.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If recycled polymer materials are used for cable coating layers, then environmental sustainability and cost reduction are improved, but mechanical properties and surface appearance deteriorate
Solution Approach 1:
The patent uses composite materials by blending recycled linear low density polyethylene (r-LLDPE) with ethylene-vinyl acetate copolymer (EVA) in specific proportions (70-95% r-LLDPE and 5-30% EVA). This composite approach allows the recycled polymer to maintain its environmental benefits while the EVA component compensates for mechanical property deficiencies, achieving tensile strength and elongation at break comparable to virgin polymers.
2Reliability
If recycled polymer materials are used for cable coating layers, then environmental sustainability and cost reduction are improved, but surface appearance and stickiness deteriorate
Solution Approach 1:
The EVA component in the composite blend improves surface appearance and reduces stickiness. The vinyl acetate groups in EVA provide better surface properties and compatibility, preventing the sticky surface issue commonly associated with recycled polyethylene while maintaining a smooth, professional appearance.
Solution Approach 2:
The patent optimizes the compositional parameters by controlling the ratio of r-LLDPE to EVA within specific ranges (70-95% and 5-30% respectively). This parameter optimization ensures that the recycled polymer content remains high for environmental benefits while the EVA content is sufficient to prevent stickiness and provide good surface appearance.
3Strength
If virgin polymer material is mixed with recycled polymer material to improve mechanical properties, then mechanical properties are improved, but environmental and economic advantages are reduced
Solution Approach 1:
The patent changes the material parameter by using ethylene-vinyl acetate copolymer (EVA) instead of virgin polyethylene to blend with recycled material. This allows achieving adequate mechanical properties (tensile strength 15-35 MPa, elongation at break 300-600%) with up to 95% recycled content, thereby maintaining environmental advantages while meeting performance requirements.
Data Source
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AI summary
Cable comprising: a core comprising a transmissive element, and a coating layer made of a coating material, said coating material comprising: (i) a recycled linear low density polyethylene (r-LLDPE) in an amount of from 70% to 95% by weight, for example from 80% to 90% by weight; and (ii) an ethylene-vinyl acetate copolymer (EVA) in an amount of from 5 to 30% by weight, for example from 10% to 20% by weight; the weight percentages being expressed with respect to the total weight of polymeric materials present in the composition. The coating layer shows mechanical properties comparable to those of a virgin polymer composition and better, both before and after ageing, than recycled polymer-based compositions comprising recycled LLDPE but free from EVA. The EVA may be added to the r-LLDPE or, alternatively, be already contained in the r-LLDPE as a result of the previous LLDPE use. The cable may further comprise a skin layer placed around and in direct contact with the coating layer based on r-LLDPE.