Cationic Polymer Fabric Softener Coacervate Residue Reduction
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Solution Overview
Problem
Conventional fabric softeners often lead to a buildup on fabrics, causing an undesirable heavy feel and fading of colors due to the abrasive damage during washing, and existing formulations face challenges in maintaining the appearance and softness of clothes over time without leaving residues.
Innovation Solution
A fabric treatment composition comprising a cationic polymer with a weight-average molecular weight of 10,000 to 600,000 Daltons and a calculated cationic charge density of 2.1 to 5.5 meq/g, combined with a quaternary ammonium compound as the fabric softening active, applied during the rinse cycle to form a separated phase that deposits on fabrics, improving appearance and softness without residue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If fabric softeners are added during the rinse cycle to provide softness and freshness, then fabric softness and freshness are improved, but fabric softening actives build up on fabrics causing heavy feel and color fading
Solution Approach 1:
The invention changes the chemical parameters of the polymer by controlling molecular weight (10,000 to 600,000 Daltons) and cationic charge density (2.1 to 5.5 meq/g), which modifies how the polymer interacts with fabric and anionic surfactant carry-over to reduce buildup while maintaining softness
Solution Approach 2:
The invention creates a composite system by combining the cationic polymer with anionic surfactant carry-over from the wash cycle, forming coacervates that deposit on fabric to provide softness without the heavy buildup associated with conventional fabric softeners
2Illumination intensity
If cationic polymer is added during the rinse cycle to maintain fabric appearance by resetting fibers, then color intensity is improved, but insufficient anionic surfactant carry-over reduces deposition effectiveness
Solution Approach 1:
The invention adjusts the polymer's cationic charge density to a specific range (2.1 to 5.5 meq/g) that optimizes interaction with the limited anionic surfactant carry-over in rinse water, ensuring reliable coacervate formation and deposition even when surfactant levels are low
Solution Approach 2:
The cationic polymer acts as an intermediary that bridges the gap between limited anionic surfactant carry-over and the need for effective fabric deposition, enabling color maintenance benefits even when direct surfactant-polymer coacervate formation would be insufficient
3Shape
If high molecular weight cationic polymer is used to provide appearance benefits, then fiber resetting capability is improved, but composition viscosity increases making processing difficult
Solution Approach 1:
The invention defines a specific molecular weight range (10,000 to 600,000 Daltons) that balances two opposing requirements: higher molecular weights provide better fiber resetting capability while lower molecular weights maintain lower viscosity for easier processing and dispensing
4Illumination intensity
If cationic polymer and anionic surfactant are combined in wash-added compositions to form coacervates, then fabric appearance is improved, but cleaning effectiveness is reduced due to coacervate interference with surfactant action
Solution Approach 1:
The invention separates the cleaning function (performed by detergent anionic surfactants during the wash cycle) from the appearance enhancement function (performed by cationic polymer coacervates during the rinse cycle), allowing both functions to operate effectively without interfering with each other
Solution Approach 2:
Instead of adding cationic polymer during the wash cycle where it would interfere with cleaning, the invention inverts the timing by adding the polymer during the rinse cycle, allowing cleaning to occur first without interference, then applying the appearance-enhancing coacervates
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 effectively maintains or improves the appearance and softness of fabrics by resetting fibers and fibrils, reducing light scattering, and providing a more intense color perception while avoiding unwanted residue on fabrics or washing machines.
Implementation Method 1
water insoluble, hydrophobic particles formed from cationic polymer and anionic surfactant via a coacervate
Implementation Method 2
particles formed from cationic polymer and anionic surfactant via a coacervate
Implementation Method 3
Protruding fibers or fibrils may scatter light, and produce an optical effect of diminished color intensity
Data Source
AI summary
A fabric treatment composition having a polymer and a fabric softening active. The polymer includes a cationic repeating unit and a non-cationic repeating unit. The polymer has a weight-average molecular weight of from about 10,000 to about 600,000 Daltons. The polymer has a calculated cationic charge density of from about 2.1 to about 5.5 meq/g at a pH of between about 2 and about 8. The polymer includes less than about 0.1% by mole of a cross-linking agent. The fabric softening active includes a quaternary ammonium compound. The composition has less than about 5% by weight of the composition of an anionic surfactant.