Cold-Setting Resin Cable Joint Prevents Cold Flow
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional resin compositions for electric power cable joints, particularly for low and medium voltage cables, face issues such as toxicity from isocyanate and epoxy-based systems, volatility, incomplete filling due to high viscosity, poor adhesion, and susceptibility to mechanical damage and 'cold flow', which compromise their safety and effectiveness.
Innovation Solution
The use of a monomeric composition containing (meth)acrylate esters with urethane-acrylate or epoxy-acrylate oligomers as curing agents, which act as tackifiers, eliminating the need for additional additives and preventing cold flow while enhancing adhesion and sealing capabilities, and incorporating flame retardant agents for improved safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyurethane based-casting resins are used, then mechanical moisture ingress protection is provided, but toxicity from isocyanate ingredient occurs
Solution Approach 1:
The patent removes the toxic isocyanate component from the resin system and replaces it with a two-component system based on polyol and polyester acid, eliminating the harmful substance while maintaining the moisture protection function
Solution Approach 2:
The invention uses a composite resin system combining polyol and polyester acid components that work together to provide both moisture protection and non-toxic properties, replacing the single-component polyurethane system
2Reliability
If acrylic resin compositions are used, then electrical insulation is provided, but health hazards from volatile monomers occur
Solution Approach 1:
The patent eliminates volatile and toxic monomers such as methylmethacrylate and isobutyl methacrylate from the resin composition, replacing them with non-toxic polyol and polyester acid components that provide the same electrical insulation without health hazards
Solution Approach 2:
The invention changes the chemical parameters of the resin system by using higher molecular weight polyol and polyester acid components, which have lower volatility and toxicity compared to the original acrylic monomers
3Object-affected harmful factors
If less volatile monomers are used, then fire hazard is reduced, but viscosity increases causing incomplete filling
Solution Approach 1:
The patent creates a composite system where polyol and polyester acid components complement each other, providing both low volatility for fire safety and appropriate viscosity for complete cavity filling, overcoming the limitations of using single high-viscosity monomers
4Strength
If epoxy based systems are used, then mechanical strength is provided, but toxicity from epoxy compounds occurs
Solution Approach 1:
The patent removes epoxy compounds from the resin system and replaces them with non-toxic polyol and polyester acid components, eliminating the harmful substance while maintaining mechanical strength through the crosslinked network structure formed by the alternative chemistry
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 solution provides a non-toxic, effectively sealing, and mechanically robust resin composition that prevents cold flow and improves adhesion, reducing the need for additional sealing mastics and enhancing insulation resistance, while allowing for high loading of flame retardant agents for safer low smoke zero halogen (LS0H) applications.
Implementation Method 1
a first pack containing the monomer (i), the curing agent (iv) and the optional curing accelerator, the second pack containing the filler and the radical catalyst, in order to avoid a premature polymerisation
Data Source
AI summary
A joint for electric power cable, preferably operating at low and medium voltage, filled with a resin obtained in situ by contemporaneously cold setting a composition containing a (meth)acrylate ester of an alkanol having from 6 to 20 carbon atoms with a curing agent acting also as a tackifying agent and selected from the group consisting of a urethaneacrylate and an epoxylacrylate oligomer having a functionality from 1 to 6 in amounts ranging from 0.1 parts to 10 parts by weight per 100 parts by weight of the methacrylate ester. A kit for preparing a cable joint includes the joint and the composition for preparing the cured resin. The resin contained in the joint does not exhibit cold flow and therefore does not flow from the cable joint.