Dishwasher Composition Scale Reduction via pH and Chelant Control
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Solution Overview
Problem
Commercially available dishwasher liquid products are ineffective in reducing scale build-up on dishes, particularly glassware and plasticware, during shortened wash cycles due to high alkalinity and interaction with calcium and magnesium ions, leading to increased water usage and energy consumption.
Innovation Solution
A dishwasher composition comprising a strong chelant, a weak chelant, a primary polymer with sulfonic acid monomers, and a structuring component, which maintains a pH range of 7.0 to 9.5 to sequester calcium and magnesium ions, reducing scale formation and improving cleaning performance without using silicates, carbonates, or bicarbonates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If shortened wash cycles are used, then washing time is reduced, but scale build-up on dishes increases due to higher water usage and interaction with calcium/magnesium ions
Solution Approach 1:
The patent changes the chemical parameters of the dishwasher composition by using a lower pH range (7.0-9.5) compared to conventional high pH formulations. This parameter change prevents the formation of insoluble calcium carbonate and magnesium hydroxide scale deposits that occur with traditional alkaline cleaners, thereby reducing scale build-up during shortened wash cycles
Solution Approach 2:
The patent employs a composite formulation combining multiple chelating agents (citric acid, EDTA, GLDA) with surfactants and polymers. This composite approach creates synergistic effects where the chelants bind calcium and magnesium ions, preventing scale formation while the surfactants maintain cleaning efficacy during shortened wash cycles
2Reliability
If highly alkaline chemistry is used, then cleaning performance is improved, but scale formation and filming on glassware increases
Solution Approach 1:
The patent fundamentally changes the pH parameter from conventional high alkaline (pH >10) to a moderate range (pH 7.0-9.5). This parameter change eliminates the chemical reactions between high pH and calcium/magnesium ions that cause scale formation, while maintaining effective cleaning through optimized surfactant and chelant combinations
Solution Approach 2:
The patent converts the potentially harmful interaction between alkaline chemistry and hard water ions into a beneficial system. By using chelating agents that selectively bind calcium and magnesium ions, the formulation prevents scale formation while the released alkalinity continues to provide effective grease and food soil removal
3Reliability
If conventional alkaline chemistry with silicates and carbonates is used, then cleaning effectiveness is maintained, but water usage increases in shortened cycles
Solution Approach 1:
The patent changes the chemical composition parameters by eliminating silicates and carbonates from the formulation. This parameter change prevents the formation of insoluble precipitates with calcium and magnesium ions that occur during shortened wash cycles with conventional formulations, thereby maintaining cleaning effectiveness with reduced water usage
Solution Approach 2:
The patent extracts and removes problematic ingredients (silicates, carbonates, bicarbonates) from the dishwasher formulation. This extraction eliminates the source of scale formation and filming issues that occur with conventional alkaline chemistries, allowing for effective cleaning in shortened cycles without excessive water consumption
Data Source
AI summary
A dishwasher composition includes at least one strong chelant, at least one weak chelant, a structural constituent, at least one surfactant, and a primary polymer. The primary polymer includes a copolymer having sulfonic acid monomer units and monomer units comprising one or more supplemental monomers, wherein the primary polymer comprises from 10 wt. % to 50 wt. % sulfonic acid monomer units and has a weight average molecular weight of less than or equal to 20,000 g/mol. The dishwasher composition can be a liquid or a gel and has a pH of from 7.0 to 9.5. Methods of washing articles include preparing a wash solution that includes water and the dishwasher composition, and contacting at least one article with the washing solution during at least a portion of a wash cycle of a commercially-available dishwasher.