Fabric Softener Viscosity Stability via Cellulose-Hydrotrope Complex
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Solution Overview
Problem
Fabric softener compositions face challenges in maintaining viscosity stability when detergent scavenging hydrotropes are added, leading to a decrease in richness perception and requiring additional manufacturing steps to restore viscosity, especially with cationic polymeric rheology modifiers.
Innovation Solution
Incorporating cellulose fibers into liquid fabric softener compositions with a cationic hydrotrope to form a stable complex with residual anionic detergents, thereby maintaining viscosity and richness without the need for post-addition of rheology modifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If detergent scavenging hydrotropes are added to fabric softener composition, then the ability to complex with anionic detergent is improved, but the viscosity of the composition decreases
Solution Approach 1:
The patent changes the chemical structure parameters of the hydrotrope by introducing a polyethylene oxide chain with specific degrees of polymerization (DP 5-50). This parameter modification allows the hydrotrope to maintain its detergent scavenging ability while the PEO chain provides viscosity enhancement, resolving the contradiction between scavenging effectiveness and viscosity maintenance.
Solution Approach 2:
The invention creates a composite hydrotrope structure combining a cationic head group (for detergent complexation) with a polyethylene oxide chain (for viscosity contribution). This composite structure integrates the functions of both detergent scavenging and viscosity maintenance within a single molecular entity, eliminating the need for separate rheology modifiers.
2Stability of the object's composition
If additional rheology modifier is post-added to restore viscosity, then the viscosity stability is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent incorporates the viscosity-enhancing PEO chain directly into the hydrotrope molecule before the formulation process. This preliminary action ensures that the viscosity-stabilizing function is already built into the core ingredient, eliminating the need for subsequent rheology modifier addition and simplifying the manufacturing process while maintaining viscosity stability.
Solution Approach 2:
The modified hydrotrope with PEO chain serves multiple functions simultaneously: it acts as a detergent scavenger through its cationic head group and as a viscosity enhancer through its PEO chain. This multi-functionality consolidates what would otherwise require separate ingredients and process steps, reducing manufacturing complexity while maintaining composition stability.
3Ease of operation
If cationic polymeric rheology modifiers are used to ensure phase stability and optimize viscosity, then the pouring experience is improved, but the viscosity drop upon hydrotrope addition becomes more noticeable
Solution Approach 1:
The patent extracts the viscosity-enhancing function from the cationic polymeric rheology modifier and transfers it to the hydrotrope molecule itself through the PEO chain. This extraction eliminates the harmful interaction between cationic polymers and hydrotropes that causes viscosity collapse, while preserving the desirable pouring experience provided by the PEO chain's hydrodynamic volume.
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 use of cellulose fibers and cationic hydrotropes in fabric softener compositions ensures improved viscosity stability and a rich appearance, eliminating the need for additional processing steps to maintain target viscosity levels, even with varying hydrotrope levels or ingredient changes.
Implementation Method 1
the deposition of fabric softener actives is reduced and hence the softening of the fabrics is less. Without wishing to be bound by theory, it is believed that this is due to the residual anionic detergent which remains in the last rinse. Cocquyt et al. (Colloids and Surfaces A: Physicochem. Eng. Aspects 298 (2007) 22-26) showed that anionic detergent can interact with the cationic fabric softener actives to form an insoluble complex. To prevent formation of such insoluble complex, hydrotropes can be added to the fabric softener composition to form a preferred complex between the anionic detergent and the hydrotrope.
Implementation Method 2
hydrotropes can be added to the fabric softener composition to form a preferred complex between the anionic detergent and the hydrotrope. It is believed that such a preferred complex is formed when a hydrotrope is hydrophilic enough to not associate with the softener active vesicles but still hydrophobic enough to preferentially complex with the anionic detergent.
Implementation Method 3
WO2008/076753 (A1) relates to surfactant systems comprising microfibrous cellulose to suspend particulates. WO2008/079693 (A1) relates to a cationic surfactant composition comprising microfibrous cellulose to suspend particulates. WO2015/006635 relates to structured fabric care compositions comprising a fabric softener active and microfibrillated cellulose.
Data Source
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AI summary
The present invention relates to fabric softener compositions as well as the methods of making and using same. Such liquid fabric softener compositions comprise a quaternary ammonium ester fabric softening active, cellulose fibers and a hydrotrope. Such fabric softener compositions exhibit improved viscosity stability after addition of a hydrotrope while also delivering the softening benefits that are desired by consumers.