Electrodeposition Coating for Potable Water Pipes

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Solution Overview

Problem

Existing anti-corrosive coatings for potable water pipes, particularly those using epoxy resin derived from bisphenol A, pose health concerns due to bisphenol A's estrogenic properties, and they often result in non-uniform thickness at pipe joints, leading to potential leakage and poor sealing.

Innovation Solution

A method of electrodeposition using a coating composition comprising a (meth)acrylic polymer dispersed in an aqueous medium with a cationic salt group-containing polymeric dispersant, an electrodepositable cationic resinous vehicle, and a curing agent, which is free from bisphenol A and its derivatives, ensuring uniform thickness and enhanced corrosion resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If epoxy resin derived from bisphenol A is used in electrodeposition composition, then corrosion resistance is improved, but health safety deteriorates due to estrogenic properties of bisphenol A

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidhealth safety
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes bisphenol A and its derivatives from the electrodeposition composition while maintaining corrosion resistance through alternative resin systems. The harmful substance is extracted from the formulation, replacing it with safe alternatives that achieve the same protective function without health risks.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the chemical composition parameters by substituting bisphenol A-based epoxy resins with alternative resins such as phenolic resins, amino resins, or carboxylic resin systems. This parameter change maintains the functional performance (corrosion resistance) while eliminating the harmful substance.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If conventional coating methods are used, then application is simple, but coating thickness uniformity deteriorates especially at pipe joints

Engineering Contradiction:
Improvecoating application simplicityVSAvoidcoating thickness uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent replaces conventional mechanical coating methods (brushing, rolling, spraying) with electrodeposition, an electrochemical process. This substitution uses electrical current to deposit coating material uniformly across the pipe surface, including complex joint geometries, eliminating thickness variation problems while maintaining ease of application through automated immersion coating.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 uniform, bisphenol A-free anti-corrosive coating with excellent corrosion resistance, preventing leakage and ensuring the safety of potable water while maintaining the structural integrity of the pipes.

Implementation Method 1

applying by electrodeposition a coating composition to a segment of pipe

Methodology Applied
Scientific EffectElectrodeposition: Electrodeposition

Implementation Method 2

polymerizing in the presence of a cationic salt group containing polymeric dispersant a polymerizable ethylenically unsaturated monomer composition

Methodology Applied
Scientific EffectPolymerization: Photopolymerisation

Implementation Method 3

a curing agent reactive with the active hydrogen groups

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentEP3122823B1Method for coating pipe segments
Publication Date: 2019.05.08 PPG INDUSTRIES OHIO INC

AI summary

A method for coating a segment of pipe is disclosed. The method comprises applying by electrodeposition a coating composition to the segment of pipe wherein the coating composition comprises: (i) a (meth)acrylic polymer dispersed in aqueous medium prepared by polymerizing in the presence of a cationic salt group containing polymeric dispersant a polymerizable ethylenically unsaturated monomer composition comprising a mixture of ethylenically unsaturated monomers at least one of which contains at least two ethylenically unsaturated groups per molecule; (ii) an electrodepositable cationic resinous vehicle containing active hydrogen groups; and (iii) a curing agent reactive with the active hydrogen groups.