Polyethylene Pipe with Bisphenol Monoester for Chlorinated Water
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Solution Overview
Problem
Pipes made from bimodal polyethylene compositions have a shortened lifetime when exposed to chlorinated disinfectants commonly used in water treatment, such as chlorine dioxide, chloramine, and chlorine, leading to material degradation.
Innovation Solution
A pipe produced with a polymer composition comprising multimodal polyethylene and a bisphenol monoester, specifically formulated to enhance resistance to chlorinated disinfectants, with a preferred composition of higher than 95.0 wt% polyethylene and lower than 1.0 wt% bisphenol monoester, which provides improved protection against chlorine dioxide and extends the pipe's service lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pipes are made from bimodal polyethylene compositions, then they have very good resistance to water, but their lifetime is shortened when exposed to chlorinated disinfectants
Solution Approach 1:
The patent uses a composite material system consisting of multimodal polyethylene (combining different molecular weight distributions) with specific stabilizer packages ( hindered phenols, phosphites, and thioesters) to achieve both water resistance and improved resistance to chlorinated disinfectants. This composite approach allows the pipe material to maintain its excellent water resistance while gaining protection against degradation from chlorine dioxide and other chlorinated compounds through the synergistic action of multiple stabilizers.
Solution Approach 2:
The patent changes the molecular parameters of the polyethylene by using multimodal distributions with specific weight average molecular weights (Mw) and number average molecular weights (Mn), along with controlled density ranges. These parameter changes in the base polymer, combined with optimized stabilizer concentrations, improve the overall resistance to chlorinated disinfectants while maintaining good water resistance properties.
2Reliability
If additives such as antioxidants and stabilizers are applied to prevent degradation, then protection against chlorinated disinfectants is improved, but the complexity of additive selection and combination increases
Solution Approach 1:
The patent applies different types of stabilizers at specific concentration ranges to address different degradation mechanisms caused by chlorinated disinfectants. Hindered phenols (0.01-0.5 wt%) provide radical scavenging, phosphites (0.01-0.5 wt%) offer phosphorus-based stabilization, and thioesters (0.01-0.5 wt%) provide sulfur-based protection. This localized optimization of different stabilizer types at appropriate concentrations reduces the complexity of selection while achieving comprehensive protection.
Solution Approach 2:
The patent merges multiple stabilizer functions into a coordinated package where hindered phenols, phosphites, and thioesters work synergistically together. This combination approach consolidates the protection against various degradation pathways (oxidation, chlorination, hydrolysis) into a single integrated stabilizer system, simplifying the overall additive selection process while maintaining effective protection against chlorinated disinfectants.
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 pipe exhibits improved resistance to chlorinated disinfectants, resulting in a longer service lifetime and ability to transport both drinking and waste water, with specific bisphenol monoester concentrations between 0.05 and 0.4 wt% offering optimal protection against chlorine dioxide.
Implementation Method 1
a bisphenol monoester... which provides improved protection against chlorine dioxide and extends the pipe's service lifetime
Data Source
AI summary
The invention relates a pipe for drinking water distribution with improved resistance to chlorinated disinfectants characterised in that the pipe is produced with a polymer composition comprising a polyolefin and a bisphenol monoester.