Liquid Detergent Composition with Cationic Polysaccharide for Fabric Softening

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Solution Overview

Problem

Current laundry softening systems fail to provide consistently improved softness and stability to fabrics across multiple wash cycles, leading to harsh fabric feel and color loss.

Innovation Solution

A liquid detergent composition comprising nonionic surfactant, anionic surfactant, fatty acid or salt, and cationic polysaccharide-based polymer, with a specific weight ratio of nonionic to anionic surfactant between 1.25:1 and 2.25:1, and a total surfactant level of at least 25 wt.%, which is applied during the main wash and allows fabrics to dry or tumble-dry for enhanced softening and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional laundry softening systems are used, then some softening effect is achieved, but the softness is not consistent across multiple wash cycles and fabric stability deteriorates

Engineering Contradiction:
Improvefabric stabilityVSAvoidconsistent softness
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent combines cationic polysaccharide-based polymer with anionic surfactant to form a composite softening system. This composite approach creates synergistic effects where the cationic polymer provides consistent softening across wash cycles while the anionic surfactant enhances stability, resolving the contradiction between consistent softness and fabric stability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent specifies precise parameter ranges: cationic polysaccharide polymer at 0.1-5% by weight, anionic surfactant at 1-20% by weight, and a weight ratio of cationic polymer to anionic surfactant from 1:10 to 5:1. These controlled parameter changes ensure both consistent softness and fabric stability across multiple wash cycles.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If higher levels of softening agents are used, then improved softening is achieved, but fabric wear and color loss increase

Engineering Contradiction:
Improvefabric softnessVSAvoidfabric wear and color loss
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent optimizes the concentration parameters of softening agents to achieve the softest fabric feel without excessive wear. The cationic polysaccharide polymer is used at 0.1-5% and anionic surfactant at 1-20%, with specific weight ratios that maximize softness while minimizing harmful effects on fabric integrity and color retention.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes the electrostatic attraction between cationic polysaccharide polymer and anionic surfactant, which normally could cause instability, to create a stable complex that deposits evenly on fabric. This converts the potential harmful interaction into a beneficial mechanism for consistent softness application without increased wear.

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

3Ease of operation

If cationic polymer and anionic surfactant are combined, then softening effect is enhanced, but formulation stability becomes difficult to maintain

Engineering Contradiction:
Improvesoftening effectVSAvoidformulation stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent defines specific parameter ranges and ratios that stabilize the cationic-anionic combination: cationic polysaccharide polymer at 0.1-5% by weight, anionic surfactant at 1-20% by weight, and a weight ratio from 1:10 to 5:1. These controlled parameters prevent phase separation and maintain formulation stability while preserving the enhanced softening effect.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a stable composite system where cationic polysaccharide polymer and anionic surfactant form a compatible combination. This composite approach, with specifically controlled ratios and concentrations, resolves the instability issue while maintaining the synergistic softening effect of the combined components.

Inventive Principle:
Principle #40Composite materials

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 composition delivers superior fabric softening, reduces wear and pilling, and provides antistatic benefits, maintaining fragrance and color retention, while maintaining stability and effectiveness over multiple washes.

Implementation Method 1

a liquid detergent composition comprising nonionic surfactant, anionic surfactant, fatty acid or salt, and cationic polysaccharide-based polymer

Methodology Applied
Scientific EffectElectrostatic attraction: Ion Repulsion/Attraction

Implementation Method 2

nonionic surfactant, anionic surfactant

Methodology Applied
Scientific EffectSurface tension reduction: Surfactant

Data Source

PatentEP2366008B1Laundry compositions
Publication Date: 2012.09.05 UNILEVER PLC

AI summary

The present invention relates to a liquid detergent composition comprising at least 25 wt.% surfactant, comprising (a) nonionic surfactant, (b) anionic surfactant, (c) fatty acid or salt thereof and (d) a cationic polysaccharide-based polymer, wherein weight ratio of (a) to (b) is from 1.25:1 to 2.25:1; the composition being useful in providing fabric softness during laundering.