Cationic Polymer Thickener for Fabric Softeners via Inverse Emulsion
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Solution Overview
Problem
Existing thickeners for fabric softeners and cleaning compositions face challenges in deposition, shear dilution, stability, and viscosity, particularly in maintaining effective performance across multiple washing cycles without residue or graying, and require improvements in rheological properties and redispersion capabilities.
Innovation Solution
A cationic polymer thickener is prepared through inverse emulsion polymerization at a constant temperature of at least 40°C, using a combination of cationic, anionic, and nonionic monomers, along with associative monomers and a crosslinker, which enhances deposition, stability, and shear dilution, and allows for rapid redispersion and thickening without additional energy input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing thickeners are used in fabric softeners and cleaning compositions, then basic thickening function is provided, but deposition performance, stability, and shear dilution properties are insufficient, leading to residue and graying issues
Solution Approach 1:
The patent modifies the chemical structure of the polymer by incorporating specific cationic monomers (such as dimethylaminoethyl methacrylate) and associative monomers with defined alkyl chain lengths (C16-C22). The polymerization is conducted at controlled temperatures (50-90°C) to achieve optimal molecular weight and architecture. These parameter changes in monomer selection, composition ratios, and polymerization conditions result in improved deposition performance and reduced residue formation while maintaining thickening functionality
Solution Approach 2:
The patent creates a composite polymer system by copolymerizing multiple monomer types including cationic monomers, associative monomers, and crosslinkers in specific ratios. This composite structure combines the benefits of each monomer type: cationic monomers provide fabric softening and deposition, associative monomers enhance thickening and stability, and crosslinkers improve structural integrity. The synergistic interaction among different monomer components resolves the contradiction between achieving reliable deposition and preventing harmful residue effects
2Ease of manufacture
If conventional emulsion polymerization is used to prepare thickeners, then polymer synthesis is achieved, but the rheological properties and redispersion capabilities are inadequate
Solution Approach 1:
The patent employs inverse emulsion polymerization methodology where the polymerization occurs in a water-in-oil emulsion system rather than the conventional oil-in-water system. This dynamic approach allows for better control of polymer particle formation and size distribution. The process involves preparing an emulsion with water, monomers, and emulsifiers, then polymerizing at elevated temperatures (50-90°C) to form particles with optimized rheological properties that can readily redisperse in aqueous formulations without requiring additional energy input
Solution Approach 2:
The patent uses specific emulsifiers as intermediaries in the inverse emulsion polymerization process. These emulsifiers facilitate the formation of stable water-in-oil emulsions during polymerization and ensure proper particle dispersion. The emulsifiers act as mediators between the hydrophobic polymer matrix and the aqueous phase, enabling the polymer to maintain stable rheological properties and exhibit excellent redispersion capability in surfactant-containing formulations after synthesis
3Productivity
If high concentrations of thickener are used to achieve sufficient viscosity, then thickening performance is improved, but the formulation becomes less efficient and more costly
Solution Approach 1:
The patent achieves high thickening performance at low concentrations by optimizing the polymer's molecular parameters including degree of polymerization, molecular weight distribution, and monomer composition. The use of associative monomers with specific alkyl chain lengths (C16-C22) and controlled crosslinking creates a polymer architecture that maximizes water interaction and viscosity generation efficiency. This allows the thickener to be effective at concentrations as low as 0.1-5% by weight, significantly reducing the quantity of substance required compared to conventional thickeners
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 resulting thickener exhibits improved deposition of active ingredients, enhanced stability, and efficient shear dilution, reducing residue and graying, while maintaining high thickening performance even at low concentrations, and allowing for rapid redispersion and thickening in surfactant-containing formulations.
Implementation Method 1
a cationic polymer is prepared by inverse emulsion polymerization at a constant temperature of at least 40° C.
Implementation Method 2
the components used in the inverse emulsion polymerization are at least one water-soluble, ethylenically unsaturated monomer comprising at least one cationic monomer, and at least one ethylenically unsaturated associative monomer
Data Source
AI summary
The present invention relates to a thickener preparable by a process which comprises obtaining a cationic polymer by inverse emulsion polymerization ofa) at least one water-soluble ethylenically unsaturated monomer comprising at least one cationic monomer, optionally at least one anionic monomer and/or optionally at least one nonionic monomer,b) at least one ethylenically unsaturated associative monomer,c) optionally at least one crosslinker,d) optionally at least one chain transfer agent,the temperature being kept constant during the inverse emulsion polymerization and being at least 40° C., preferably 50 to 90° C., and after the inverse emulsion polymerization has ended, activator being added to obtain the thickener.