Ethyl Cellulose (EC) is a chemically modified cellulose derivative widely used in cosmetics, pharmaceuticals, foods and daily chemicals, especially in the thickening of liquid soap. Liquid soap is a common cleaning product, mainly composed of surfactants, water and some thickeners, moisturizers and other ingredients. In order to increase the viscosity of liquid soap, improve the feeling of use and enhance its physical stability, the use of thickeners is one of the common processes. As a thickener, ethyl cellulose has excellent thickening properties and other unique advantages, and has been increasingly used in the production process of liquid soap.

Properties of Ethyl Cellulose
Ethyl cellulose is a non-ionic cellulose derivative obtained by reacting cellulose with ethyl groups. It is a white or slightly yellow powder that is almost insoluble in water, but soluble in organic solvents (such as alcohols, ethers, ketones, etc.). The molecular structure of ethyl cellulose contains many hydroxyl and ethyl substituents, which give it good adhesion, thickening and film-forming properties. Because of its poor solubility in water, it is often used as a dispersant or thickener in the water phase during the thickening process of liquid soap.

The thickening effect of ethyl cellulose is to form a three-dimensional network structure through the interaction of the hydroxyl and ethyl groups in its molecular structure with the water and other ingredients in the liquid soap, thereby increasing the viscosity of the soap. At a certain concentration, ethyl cellulose can effectively increase the consistency of liquid soap, improve its rheological properties, and make it more operable and comfortable to use.

Application of ethyl cellulose in liquid soap
In the formulation of liquid soap, ethyl cellulose is usually used as a thickener or stabilizer. Its main functions are:

Increase viscosity: The viscosity of liquid soap has an important impact on its use experience and quality. The use of ethyl cellulose can significantly increase the viscosity of the soap liquid, making the liquid soap easier to control when using it, while increasing the comfort of use.

Improve rheological properties: The fluidity of liquid soap needs to be controlled within a certain range to ensure the smooth flow of the product in a pump bottle or a press bottle. Ethyl cellulose can form a viscous network structure, which can make liquid soap maintain good rheological properties in various environments and is not prone to “stratification”.

Improve stability: Ethyl cellulose can improve the physical stability of liquid soap and reduce the separation between soap ingredients. Especially when a variety of other ingredients (such as fragrances, moisturizers, etc.) are added to the soap, ethyl cellulose helps prevent these ingredients from stratifying due to density differences.

Improve sensory experience: Ethyl cellulose can sometimes provide a silky touch, making the liquid soap more foamy and smoother when used, improving the user experience.

Formulation design using ethyl cellulose
In the formulation design of liquid soap, the amount of ethyl cellulose used usually depends on the type of soap liquid and the expected viscosity. Generally speaking, the concentration of ethyl cellulose ranges from 0.5% to 2%, and the specific concentration needs to be adjusted according to the production process and target viscosity. The following is a simple liquid soap thickening formula example:

Example formula (per 1000g liquid soap):
Surfactant (such as sodium dodecylbenzene sulfonate): 12-18%
Water: 70-75%
Ethyl cellulose: 0.5-1.5%
Fragrance: appropriate amount
Humectant (such as glycerin): 2-5%
pH adjuster (such as citric acid): appropriate amount
Other ingredients such as humectants, stabilizers and additives can be added to the formula in appropriate amounts as needed to achieve specific product effects.

Precautions when using ethyl cellulose
Dissolution process: Ethyl cellulose dissolves slowly in water, especially in cold water. Therefore, when preparing liquid soap, the dissolution of ethyl cellulose should be carried out at an appropriate temperature, preferably with warm water and sufficient stirring to avoid agglomeration.

Dosage control: The thickening effect of ethyl cellulose depends on its concentration, but too high a dosage may make the soap too thick and affect pumpability. Therefore, the dosage needs to be optimized according to actual needs and test results.

Compatibility with other ingredients: Ethyl cellulose has good compatibility with many common surfactants and moisturizers, but some high concentrations of salts and acids may affect its thickening effect. Appropriate compatibility testing is required in formula development.

As an efficient thickener, ethyl cellulose plays an important role in the production of liquid soap. It can significantly improve the quality and user experience of liquid soap by increasing the viscosity of liquid soap, improving rheological properties, improving stability and improving the feeling of use. However, when using ethyl cellulose, it is also necessary to adjust its dosage and usage method according to product requirements and production conditions to ensure the ideal effect of the final product.