Detergent Composition with Dynamic pH Control for Stain Removal

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Solution Overview

Problem

Current detergents face challenges in completely removing difficult stains, particularly those composed of complex mixtures like carbohydrates and plant material, leading to residue buildup, discoloration, and fabric wear, and there is a need for improved cleaning methods that maintain fabric color, tensile strength, and prevent dye transfer.

Innovation Solution

The method involves using a wash liquor with a perhydrolase enzyme, hydrogen peroxide, and a substrate with an ester moiety, where the initial alkaline pH is adjusted to drop to less than 6.5, allowing dynamic pH control to enhance cleaning performance and denature soils.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional detergents are used to clean stains, then cleaning action is provided, but stain removal is incomplete and residue buildup occurs

Engineering Contradiction:
Improvestain removal efficiencyVSAvoidresidue buildup
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The patent employs dynamic pH control by combining an alkaline detergent composition with an acidifying agent that releases acid during the wash cycle. This dynamic adjustment of pH allows the system to optimize cleaning performance at different stages: alkaline conditions for initial stain loosening and surfactant action, then acidic conditions for stain removal and residue prevention, resolving the contradiction between complete stain removal and residue prevention

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the pH parameter dynamically during the washing process. The detergent composition maintains alkaline pH for surfactant effectiveness, while the acidifying agent (such as vitamin C, citric acid, or lactic acid) progressively lowers pH to remove stains and prevent residue buildup. This parameter change strategy enables the system to achieve both complete stain removal and minimal residue

Inventive Principle:
Principle #35Parameter changes

2Productivity

If strong cleaning agents are used to remove difficult stains, then cleaning performance improves, but fabric wear and color loss increase

Engineering Contradiction:
Improvecleaning performanceVSAvoidfabric wear and color loss
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The dynamic pH adjustment from alkaline to acidic conditions provides progressive cleaning action that is effective yet gentle. The alkaline phase loosens stains without aggressive damage, while the subsequent acidic phase removes stains and prevents residue without the need for harsh bleaching agents. This dynamic approach maintains fabric integrity and color while achieving superior cleaning performance

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent converts the typically harmful effect of pH change into a benefit by using controlled acidification to achieve both stain removal and fabric protection. The acidifying agent, when used in controlled amounts, provides stain removal power while simultaneously preventing residue buildup and minimizing fabric damage, turning what could be a damaging factor into a protective mechanism

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Loss of energy

If low wash temperatures are used to conserve energy, then energy consumption decreases, but stain removal capability is reduced

Engineering Contradiction:
Improveenergy consumptionVSAvoidstain removal capability
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The invention compensates for low temperature by optimizing the pH parameter. The alkaline environment enhances surfactant effectiveness and stain loosening at low temperatures, while the subsequent acidification provides potent stain removal action. This parameter optimization allows the system to achieve effective stain removal at energy-saving low wash temperatures without relying on thermal energy

Inventive Principle:
Principle #35Parameter changes

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

This approach provides superior cleaning benefits by utilizing enzymes effectively within their optimal pH range, improving stain removal, maintaining fabric color, and restoring tensile strength, while also preventing dye transfer and residue buildup.

Implementation Method 1

contacting the surface and/or fabric with a wash liquor comprising: a perhydrolase enzyme, hydrogen peroxide and/or a source of hydrogen peroxide, and a substrate for the enzyme, comprising an ester

Methodology Applied
Scientific EffectEnzyme catalysis: Enzyme

Implementation Method 2

the amount of perhydrolase enzyme and substrate is sufficient to drop the pH of the wash liquor to a pH of less than 6.5

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 3

hydrogen peroxide and/or a source of hydrogen peroxide

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 4

there remains a need for compositions that are capable of removing the colored components of stains

Methodology Applied
Scientific EffectBleaching:

Data Source

PatentEP1991651B2Surface active bleach at dynamic ph
Publication Date: 2022.07.06 PROCTER & GAMBLE CO
  • EP1991651B2 patent drawingFigure 1A~1C
  • EP1991651B2 patent drawingFigure 2
  • EP1991651B2 patent drawingFigure 3A~3C

AI summary

The present invention provides methods and compositions for dynamic pH control, particularly in detergent applications. In particularly preferred embodiments, the detergent compositions find use in surface removal of soils from fabrics, including clothing. In some particularly preferred embodiments, the present invention provides combinations of enzymes to provide for dynamic pH control.