Copper Refrigerant Pipe Anticorrosive Coating for Acidic Environments
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Solution Overview
Problem
Existing refrigerant pipes made of copper are prone to corrosion, which can lead to leaks, and existing solutions focus on benzotriazole compounds, with no studies on alternative materials for corrosion suppression.
Innovation Solution
A copper-containing refrigerant pipe with an anticorrosive film formed using organic sulfonate compounds, polyhydric alcohol-organic acid ester compounds, and aliphatic amine compounds, specifically with amounts and combinations that enhance corrosion resistance, applied in a coating agent and dried under controlled temperatures to ensure film fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If copper is used for refrigerant pipes, then good thermal conductivity and ease of manufacture are achieved, but corrosion resistance deteriorates leading to leaks
Solution Approach 1:
The patent applies a coating film comprising multiple anticorrosive agents (benzotriazole compound, carboxylic acid compound, and sulfur compound) on the copper pipe surface. This creates a composite structure where the copper base material provides thermal conductivity and manufacturability, while the multi-component coating film provides enhanced corrosion resistance against both general and acidic corrosion.
Solution Approach 2:
The patent optimizes the concentration ratios of different anticorrosive agents in the coating film. Specifically, it controls the ratio of carboxylic acid compound to benzotriazole compound within 0.01 to 10 by mass, and sulfur compound to benzotriazole compound within 0.01 to 10 by mass. This parameter optimization ensures effective corrosion suppression while maintaining coating film integrity and preventing refrigerant leakage.
2Reliability
If benzotriazole compound coating is applied, then general corrosion is suppressed, but acidic corrosion resistance is insufficient
Solution Approach 1:
The patent combines multiple types of anticorrosive agents with different mechanisms of action: benzotriazole compound (forms protective complex with copper), carboxylic acid compound (provides acid neutralization and additional passivation), and sulfur compound (enhances corrosion resistance through sulfide layer formation). This combination synergistically addresses both general corrosion and acidic corrosion that cannot be effectively suppressed by benzotriazole alone.
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 effectively suppresses corrosion in copper-containing refrigerant pipes, preventing leaks and maintaining pipe integrity, even in acidic environments, and can be used in heat exchangers to reduce refrigerant leakage.
Implementation Method 1
an anticorrosive film is formed on the outer surface of a copper-containing refrigerant pipe by applying a coating agent including a specific benzotriazole compound and a metalworking fluid to thereby suppress corrosion of the refrigerant pipe
Data Source
AI summary
Provided are a copper-containing refrigerant pipe whose corrosion can be suppressed, a heat exchanger, and a method for producing a refrigerant pipe. A refrigerant pipe includes a pipe body including copper or copper alloy and an anticorrosive film formed on the outer surface of the pipe body. The anticorrosive film is obtained by applying a coating agent to the outer surface of the pipe body. The coating agent contains one or more anticorrosive agents selected from (A) an organic sulfonate compound, (B) a polyhydric alcohol-organic acid ester compound, and (C) an aliphatic amine compound having 8 to 24 carbon atoms. When the coating agent includes an anticorrosive agent of (C) the aliphatic amine compound having 8 to 24 carbon atoms, (C) the aliphatic amine compound having 8 to 24 carbon atoms is included in an amount of 2.0 wt % or more and 10.0 wt % or less in the coating agent.