Metalworking Fluid pH Buffer System for Corrosion Prevention

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Solution Overview

Problem

Metalworking fluids containing boric acid pose safety concerns due to their toxic nature, and existing pH buffering systems are not adequately effective in preventing corrosion and maintaining optimal pH levels without causing skin and metal surface irritation.

Innovation Solution

A metalworking fluid composition using a pH buffer system comprising organic acids like phthalic acid, isophthalic acid, and terephthalic acid in combination with organic amines such as monoethanolamine and methylpentamethylenediamine, which maintains a pH range of 8.5 to 10.0, replacing boric acid and providing effective corrosion prevention and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If boric acid and its salts are used as pH buffers in metalworking fluids, then the fluid can maintain optimal pH levels and prevent corrosion, but the fluid becomes toxic and harmful to human health

Engineering Contradiction:
Improvecorrosion preventionVSAvoidtoxicity
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes boric acid and its salts from the metalworking fluid composition entirely, extracting the harmful substance while maintaining the essential pH buffering function through alternative organic acids and organic amine combinations that provide corrosion protection without toxicity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces organic acid/organic amine buffer systems as intermediary substances that perform the same pH control and corrosion prevention functions as boric acid but without its toxic effects, serving as safe mediators between the metalworking fluid and the metal surfaces

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If highly alkaline fluids with pH 9.5 or higher are used, then emulsifier performance and corrosion prevention are improved, but skin irritation and metal surface damage occur

Engineering Contradiction:
Improvecorrosion preventionVSAvoidskin irritation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent optimizes the pH range to 8.5-10.0, moving away from highly alkaline conditions (pH 9.5+) while maintaining effective corrosion protection through carefully selected organic acid and organic amine concentrations, thereby reducing skin irritation and mist-related health hazards

Inventive Principle:
Principle #35Parameter changes

3Reliability

If pH is maintained above 8.0, then steel alloy corrosion is reduced, but aluminum and yellow metals begin to stain or dissolve

Engineering Contradiction:
Improvesteel corrosion preventionVSAvoidmetal surface damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies different buffering components and concentrations tailored to specific metal types being processed, using organic acid/organic amine combinations that provide appropriate pH control for each metal category (steel, aluminum, yellow metals) to prevent both corrosion and surface damage

Inventive Principle:
Principle #3Local quality

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 buffers the pH of metalworking fluids, preventing corrosion and reducing skin irritation while eliminating the hazards associated with boric acid, ensuring safer and more stable metalworking processes.

Implementation Method 1

a pH buffer system, the pH buffer system comprising one or more organic acids selected from the group consisting of phthalic acid, isophthalic acid, and terephthalic acid and one or more organic amines selected from monoethanolamine, methylpentamethylenediamine, and mixtures thereof

Methodology Applied
Scientific EffectpH buffering:

Implementation Method 2

Because these two fluids are immiscible, an emulsifier is commonly incorporated into the metalworking composition to ensure that the fluid remains well-mixed

Methodology Applied
Scientific EffectEmulsion: Emulsion

Implementation Method 3

The metalworking fluid also acts as a lubricant, which provides the advantage of reducing friction and tool wear

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 4

In order to remove the heat generated during metalworking processes, a fluid is applied to the tool/workpiece contact surfaces to efficiently and rapidly cool the tool and workpiece

Methodology Applied
Scientific EffectHeat transfer:

Data Source

PatentEP3394230B1Metalworking fluid
Publication Date: 2020.10.21 HENKEL KGAA

AI summary

A metalworking fluid includes a pH buffer system having one or more organic acids and one or more organic amines. The organic acids, which include aromatic carboxylic acids and C10 or higher aliphatic carboxylic acids, may replace boric acid, such that boric acid may be excluded from the metalworking fluid. The organic acids may include at least one of phthalic acid, isophthalic acid, and terephthalic acid. The one or more organic amines include aliphatic and aromatic amines having an amine value of at least 50 mg KOH/g. A method of using the metalworking fluid includes shaping a metal by contacting the metal surface with a tool while cooling and lubricating at least one of the metal surface or tool with the metalworking fluid.