Industrial Garment Laundering With HEDP Pre-Wash for Metallic Oily Soils
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for removing hydrocarbon-based oily soils from industrial garments, particularly those with metallic components, often leave residual stains due to limited solubility and effectiveness of oxalic acid, which is the only known acid for treating these soils.
Innovation Solution
A pre-wash step using hydroxy diphosphonic acid, such as 1-hydroxy ethylidene-1,1-diphosphonic acid (HEDP), is employed under acidic conditions followed by a standard alkaline laundering process to effectively remove metallic-based oily soils, utilizing a concentrated liquid form of HEDP with a pH range of 3 to 3.5 to ensure effective soil removal without damaging textiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxalic acid is used to remove metallic-based oily soils, then the metallic component valence is changed to make it more water soluble, but the limited solubility in water (50% liquid) restricts its effectiveness
Solution Approach 1:
The patent changes the chemical parameter from oxalic acid to hydroxy diphosphonic acid (HEDP), which has superior water solubility and effectiveness. HEDP is available in concentrated liquid form with greater than 50% solids, allowing for better dissolution and distribution in the wash liquor, thereby resolving the solubility limitation of oxalic acid while maintaining or enhancing the ability to treat metallic-based oily soils
2Reliability
If oxalic acid is used to treat oily metallic soils, then the metallic component is made more water soluble, but residual stains remain on the garment after processing
Solution Approach 1:
The patent changes the chemical agent from oxalic acid to hydroxy diphosphonic acid (HEDP), which provides superior soil removal performance. HEDP effectively treats the oily metallic soils and prevents residual staining, delivering cleaner garments after the washing process while maintaining the ability to change metal valence for water solubility
3Ease of operation
If concentrated liquid form of HEDP is used, then it is suitable for dispensing using automatic dispensing equipment, but the concentration must be precisely controlled to maintain pH range of 3 to 3.5
Solution Approach 1:
The concentrated liquid form of HEDP is designed to be self-regulating in terms of pH control. When dispensed in the correct amounts by automatic dispensing equipment, the HEDP solution naturally maintains the required pH range of 3 to 3.5, reducing the need for additional pH adjustment steps and simplifying the overall process while ensuring consistent performance
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 HEDP pre-wash significantly reduces metallic-based residual stains, allowing for cleaner garments and maintaining the integrity of reflective tape properties, while being suitable for use with automatic dispensing equipment and effective in removing lead contamination.
Implementation Method 1
oxalic acid to change the valence of the metal to make it more water soluble
Implementation Method 2
Surfactants are used as a means to remove hydrocarbon based oil, lowering the surface tension at the fabric/soil-water interface and creating an emulsion as the oily soils are lifted from the fabric and suspended in the wash liquor
Data Source
AI summary
Metallic based oily soils can be removed from garments by subjecting the garments to a pre-wash in an aqueous solution of a hydroxy diphosphonic acid such as HEDP under acidic conditions. Pre-washing the garments in the aqueous solution of HEDP at about 100 to 212 degrees Fahrenheit for about 15 minutes effectively removes the greasy soils, allowing them to be further laundered with an alkaline detergent composition.