Acidic Flush Removes Chlorhexidine Stains from Fabric
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Solution Overview
Problem
Chlorhexidine and avobenzone pose significant staining challenges for fabric materials in institutional laundry settings, as they bind to fibers during the flush cycle, especially with chlorine-based oxidants, and current laundry processes either mask or fade these stains rather than effectively removing them.
Innovation Solution
Conducting the flush cycle with an acidic detergent composition containing phosphoric acid and a surfactant, which creates a pH of less than 5, frees chlorhexidine and avobenzone from fabric fibers, allowing them to be carried away with the flush solution, thereby reducing or eliminating staining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flush cycle uses chlorine-based oxidants (high chlorine content liquid), then the disinfection effectiveness is improved, but chlorhexidine and avobenzone bind to fabric fibers causing irreversible staining
Solution Approach 1:
The patent applies preliminary action by conducting the flush cycle with acidic detergent composition before the main wash and bleach cycles. This preliminary acidic flush frees chlorhexidine and avobenzone from fabric fibers before they can bind during subsequent chlorine-based washing, thereby preventing staining while maintaining disinfection effectiveness in later cycles
Solution Approach 2:
The patent changes the pH parameter during the flush cycle by using acidic detergent composition (pH < 5) instead of neutral or basic cleaners. This parameter change prevents chlorhexidine and avobenzone from binding to fabric fibers, while subsequent chlorine-based cycles maintain disinfection effectiveness
2Productivity
If the flush cycle uses high basic pH cleaners, then the cleaning power is improved, but chlorhexidine and avobenzone set or bind to fabric fibers making stain removal difficult
Solution Approach 1:
The patent uses preliminary action by performing an acidic flush cycle before the main cleaning cycles. This preliminary acidic treatment prevents chlorhexidine and avobenzone from setting in fabric fibers, allowing subsequent basic pH cleaners to effectively remove stains without causing the chemicals to bind permanently
Solution Approach 2:
The patent changes the pH parameter sequence by using acidic conditions (pH < 5) during the flush cycle and then transitioning to basic pH conditions during wash and bleach cycles. This parameter change sequence prevents chemical binding during flush while maintaining cleaning effectiveness during later cycles
3Reliability
If chlorine-based oxidants are used in subsequent wash and bleach cycles, then the disinfection and stain removal capability is improved, but the cost and process complexity increase
Solution Approach 1:
The patent applies preliminary action by using acidic detergent composition in the flush cycle to prevent chlorhexidine and avobenzone binding before the main wash and bleach cycles. This prevents the need for additional special treatment steps later, simplifying the overall process while maintaining effective stain removal
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 acidic detergent composition effectively removes or reduces chlorhexidine and avobenzone from fabric materials, preventing irreversible staining and allowing for cleaner laundry cycles with minimal risk of chemical residue.
Implementation Method 1
the flush cycle is conducted with an acidic detergent composition including phosphoric acid and a surfactant which, when mixed with the flush liquid, provides a flush solution at a pH of less than about 5
Implementation Method 2
chlorhexidine and avobenzone, when present, are typically becoming set or otherwise bound to the fibers of the fabric material during the flush cycle
Implementation Method 3
an acidic detergent composition including phosphoric acid and a surfactant which, when mixed with the flush liquid, provides a flush solution at a pH of less than about 5
Implementation Method 4
there is also a fair amount of iron in the water, which tends to further aggravate problems with avobenzone
Data Source
AI summary
A method for removing chlorhexidine and/or avobenzone from fabric materials utilizes an acidic detergent composition including phosphoric acid and a surfactant in a flush cycle of a washing machine adapted to perform separate flush, wash, and bleaching cycles. The acidic detergent composition is present in the flush solution in a sufficient quantity to provide a pH less than about 5 and, advantageously, above about 2. The acidic detergent composition is advantageously substantially free of a chlorine-based oxidant.