Multilayer Polyethylene Pipe With Hard Outer Layer for Termite Resistance
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Solution Overview
Problem
Polyethylene pipes used for water or gas distribution in certain regions, such as Asia, are vulnerable to termite attacks, leading to severe damage, and existing solutions like adding termite-resistant additives are time- and cost-consuming.
Innovation Solution
A multilayer pipe structure is proposed, featuring a polyethylene inner layer protected by an outer layer with a propylene polymer that has a shore D hardness of at least 60, incorporating a heterophasic propylene copolymer with specific comonomer content and amorphous phase characteristics to resist termite attacks while maintaining mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If termite resistant additives are added to polyethylene, then termite resistance is improved, but development time and cost increase
Solution Approach 1:
The invention extracts the termite resistance function from the polyethylene material itself and places it in a separate outer layer. This allows the polyethylene to maintain its original properties while the outer layer provides termite protection, avoiding the need to modify and re-test polyethylene formulations.
Solution Approach 2:
The outer layer acts as an intermediary between termites and the polyethylene pipe. This mediator layer contains the termite resistance properties while the polyethylene core maintains its structural and mechanical functions, separating the termite protection requirement from the material development process.
2Reliability
If termite resistant additives are added to polyethylene, then termite resistance is improved, but production cost increases
Solution Approach 1:
The pipe is segmented into two functional layers: an inner polyethylene layer for structural integrity and fluid transport, and an outer layer for termite resistance. This segmentation allows each layer to be optimized independently and manufactured using standard extrusion processes without requiring expensive additive development.
Solution Approach 2:
The outer layer serves multiple functions: providing termite resistance, protecting the polyethylene surface, and maintaining compatibility with existing manufacturing processes. This multi-functionality reduces the need for specialized materials and extensive testing.
3Reliability
If an outer layer is added for termite protection, then termite resistance is improved, but pipe structure complexity increases
Solution Approach 1:
The invention uses a composite structure with an inner polyethylene layer and an outer termite-resistant layer. This composite approach combines the advantages of both materials while maintaining a simple two-layer architecture that is easy to manufacture and install.
4Strength
If polyethylene is used for pipes, then mechanical properties are improved, but vulnerability to termite attacks increases
Solution Approach 1:
The pipe structure applies different properties to different regions: the inner polyethylene layer provides superior mechanical properties for pressure resistance and durability, while the outer layer provides termite resistance. Each layer is optimized for its specific function without compromising the other.
Data Source
AI summary
Provided is a termite resistant multilayer pipe. The pipe is a polyethylene pipe comprising: a) at least one layer (A) comprising an ethylene polymer, and b) at least one outer layer (B) comprising the polymer, said polymer being different to the ethylene polymer of the at least on layer (A), wherein the outer layer (B) has a shore D hardness measured according to ISO 868 of at least 60.