The viscosity requirements of a liquid homecare formulation can vary drastically depending on the application and are often critical to a product’s performance and consumer perception. Thickeners and rheology control additives are ingredients in homecare formulations that provide formulators precise control over the viscosity and feel of the final product.
Considerations When Choosing a Thickener
Compatibility
Thickening homecare products provides a unique challenge for formulators. Often, these formulations are highly acidic or basic and contain oxidizing agents and surfactants that can be incompatible with thickeners. Therefore, selecting a thickener compatible with these challenging environments is crucial to producing a solution with consistent viscosity and good clarity.
Rheology
The rheology, or how a solution behaves under shear stress, is also an important characteristic to consider when selecting a thickening additive. In many homecare applications, a thicker viscosity is required for cling, dwell time, or a more desirable feel. However, higher viscosities can make homecare solutions difficult to dispense or spread on surfaces. Selecting a thickener that provides a pseudoplastic, or shear-thinning, rheology allows for viscous formulations that are easier to dispense and spread.
Usage Rate
The amount of thickener required to achieve the desired viscosity can be a large factor in the formulation cost. Ideally, the selected thickener should provide the targeted viscosity at the lowest usage rate.
CELLOSIZE™ Hydroxyethylcellulose - The Ideal Thickener
CELLOSIZE™ is a line of nonionic, water-soluble hydroxyethylcellulose polymers that are effective thickeners for water-based homecare formulations, including liquid hand soap, toilet cleaners, laundry detergent, vertical surface cleaners, gel fresheners, and various others. The features and benefits of CELLOSIZE™ hydroxyethylcellulose as thickeners in homecare formulations are listed in the table below.
Feature
Benefit
Wide range of molecular weights
Allows for precise viscosity control, creating formulas ranging from thin solutions to gels.
Good chemical compability
Easy to formulate with other ingredients, including surfactants, solvents, gums, and resins. Produces stable solutions with good clarity.
Pseudoplastic rheology
Create viscous solutions with good cling, less dripping, and a more appealing feel that are easy to dispense and spread on surfaces.
Nonionic
Tolerates both cationic and anionic surfactants as well as salts in the formulation.
pH Stability
Stable from pH 2 to 12. Produces stable viscosity in both acidic and basic systems, allowing formulation flexibility.
Viscosity stability
Improved shelf life and reduced disposal of expired or out-of-specification products.
Low usage rate
Recommended use rates range from 0.5% to 2.0%. Improved efficiency and reduced formulation cost.
How to Use CELLOSIZE™
Hydroxyethylcellulose polymers are hygroscopic powders that will agglomerate and clump when exposed to water if improperly dispersed. This can lead to lumpy, inconsistent solutions. To prevent this, CELLOSIZE™ polymers are cross-linked to delay hydration and allow for proper dispersion. A recommended procedure for producing stable homogeneous solutions of CELLOSIZE™ is outlined below.
CELLOSIZE™ should be added under agitation to a solution with a pH of 7.0 or lower, allowing CELLOSIZE™ to be thoroughly dispersed in the solution.
Once dispersion is achieved, hydration and thickening can be accelerated by increasing the temperature to increase the pH.
Once hydration is complete and the target viscosity is achieved, the solution can be adjusted to a pH between 2 and 12 without any significant effect on viscosity.
Selecting a Grade of CELLOSIZE™
CELLOSIZE™ hydroxyethylcellulose polymers range in molecular weight and should be selected based on the desired viscosity and flow properties needed for the solution. The Brookfield viscosities of various CELLOSIZE™ grades at 2% in water are listed below.
The concentration of CELLOSIZE™ can be adjusted to meet the exact viscosity requirements of a liquid formulation. In addition, the same target viscosity can be reached using different concentrations of various grades. For example, a 1% solution of QP-30000H and a 3% solution of QP-300 each provide a viscosity of 1500 cPs. However, the flow properties of these solutions are dramatically different. In general, solutions of large molecular weight grades of CELLOSIZE™ produce solutions that have more of a pseudoplastic rheology.
ChemPoint is here to help you select the right rheology-modifying ingredient for your homecare formulation. Click below to speak to one of our experts and request a sample today.
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