Hydroxyethyl Cellulose ( HEC )Used In Coating
Posted by David Li on July 9th, 2019
Cellulose ether materials such as methyl cellulose,hydorxy ethyl cellulose and hydroxypropyl methyl cellulose can be used in coating as thickener . The greatest characteristic of cellulose ether HEC is thickeners also HEC will make the coating has a certain water-retaining effect, which can delay the drying time of the coating to a certain extent.
HEC’s property – thickeners can also make the coating thixotropic to a certain extent and prevent the deposition and stratification in the storage of the coating. However, this kind of thickener can also bring the drawbacks of poor leveling of coatings, especially when using high viscosity products. Cellulose is a nutrient of microorganisms, so it should be used to strengthen anti-mildew measures.
Cellulose ether thickeners can only thicken the water phase, do not increase the thickening effect on other components of waterborne coatings, and do not produce obvious interaction between pigment and emulsion particles in coatings, thus the rheological properties of coatings can not be adjusted. Cellulose ether thickeners generally only increase the viscosity of coatings at low and medium shear rates (commonly known as KU viscosity).
As a protective colloid, HEC can be used in emulsion polymerization of vinyl acetate to improve the stability of the polymerization system in the wide pH range. In the manufacture of finished products, additives such as pigments and fillers are evenly dispersed, stabilized and provided with thickening effect. It can also be used as dispersant for suspended polymers such as styrene, acrylic resin and propylene. It can significantly improve the thickening and leveling properties of latex paint.
HEC Physicochemical Properties:
This product is white or yellowish odorless, odorless, tasteless and flowable powder, which is soluble in cold water and hot water and is insoluble in most organic solvents under normal conditions. The viscosity changes slightly in the range of 2-12 but decreases beyond this range. The surface treated HEC disperses in cold water without condensation, but dissolves slowly. 1. It usually takes about 30 minutes. It can dissolve quickly by heating or adjusting the PH value to 8-10.
40 meshes screening rate ≥99%, softening temperature: 135-140 ℃, apparent density 0.35-0.61g/ml, decomposition temperature 205-210 ℃, slow burning rate, equilibrium moisture content: 23 > C, 50% rh, 6%, 84% rh, 29%.
As a non-ionic surfactant, hydroxyethyl cellulose has the following properties besides thickening, suspension, adhesion, emulsification, film-forming, dispersing, water-holding and protection.
HEC can be dissolved in hot water or cold water. It does not precipitate at high temperature or boiling. It has a wide range of solubility and viscosity characteristics: non thermal gelatinization. Its non-ionic type can coexist with other water-soluble polymers, surfactants and salts in a wide range. It is an excellent gel thickener containing high concentration electrolyte solution.
Water retention capacity is twice as high as that of methyl cellulose and has better flow regulation.
The product has stable viscosity, mildew-proof, better pot opening effect and better leveling performance during construction.
HEC Dissolution Method：
Add a specified amount of clean water to the container.
Add hydroxyethyl cellulose at low stirring speed and stir until all the materials are completely wet.
Stir the other ingredients in the formula.
