Anti-redeposition agent and detergent composition

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Solution Overview

Problem

Existing detergent compositions lack effective antiredeposition ability, particularly in polyaspartate salts, where the weight-average to number-average molecular weight ratio (polydispersity) is not optimized, leading to inadequate prevention of dirt redeposition during washing.

Innovation Solution

A detergent composition incorporating a polyaspartic acid alkali metal salt with a polydispersity of 1.4 to 1.7, specifically lithium, potassium, or sodium polyaspartate, is used, which enhances antiredeposition ability by optimizing the molecular weight ratio and pH range from 6 to less than 9.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional polyaspartate salts are used as antiredeposition agents, then the detergent composition can prevent dirt redeposition to some extent, but the antiredeposition ability is insufficient when the polydispersity is outside the specific range

Engineering Contradiction:
Improveantiredeposition abilityVSAvoidmolecular weight distribution adaptability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies parameter changes by optimizing the polydispersity (Mw/Mn ratio) of polyaspartate salt to a specific range of 1.4-1.7, and controlling the weight-average molecular weight to be 10,000-100,000. This precise parameter optimization transforms the antiredeposition ability from insufficient to excellent, resolving the technical contradiction between reliable performance and adaptability to molecular weight variations.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If polyaspartate salt with arbitrary molecular weight distribution is used, then the detergent composition can be manufactured easily, but the antiredeposition effect is inadequate

Engineering Contradiction:
Improveantiredeposition effectVSAvoidmolecular weight control precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent specifies precise parameter ranges for polyaspartate salt: polydispersity of 1.4-1.7 and weight-average molecular weight of 10,000-100,000. These controlled parameters ensure both excellent antiredeposition effect and feasible manufacturing precision, as the ranges are narrow enough to guarantee performance but broad enough to allow practical production.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If detergent composition with pH outside the specific range is used, then the composition can be formulated with simpler ingredients, but the antiredeposition ability is significantly reduced

Engineering Contradiction:
Improveantiredeposition abilityVSAvoiddetergent composition complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent optimizes the pH parameter to the range of 6-8, which is the isoelectric point range of polyaspartate salt. This parameter optimization enhances antiredeposition ability while maintaining relatively simple composition formulation, as the pH control can be achieved through standard buffer systems without requiring complex ingredient combinations.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3778846B1Anti-redeposition agent and detergent composition
Publication Date: 2023.10.25 MITSUI CHEMICALS INC
  • EP3778846B1 patent drawingFigure 1
  • EP3778846B1 patent drawing

AI summary

An antiredeposition agent includes a polyaspartic acid alkali metal having a polydispersity, represented by the ratio (Mw/Mn) of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn), of 1.4 or more and being selected from the group consisting of lithium polyaspartate, potassium polyaspartate, and sodium polyaspartate.