The encounter between hydroxyethyl cellulose and water-based coatings

What is Hydroxyethyl Cellulose?
Hydroxyethyl cellulose (HEC), a white or light yellow, odorless, non-toxic fibrous or powdery solid, prepared by etherification reaction of alkaline cellulose and ethylene oxide (or chlorohydrin), belongs to Nonionic soluble cellulose ethers. Since HEC has good properties of thickening, suspending, dispersing, emulsifying, bonding, film-forming, protecting moisture and providing protective colloid, it has been widely used in oil exploration, coatings, construction, medicine, food, textile, papermaking and polymer Polymerization and other fields.

Hydroxyethyl cellulose is widely used in the coating industry, let us take a look at how it works in coatings:

What happens when hydroxyethyl cellulose meets water-based paint?

As a non-ionic surfactant, hydroxyethyl cellulose has the following properties in addition to thickening, suspending, binding, floating, film-forming, dispersing, water retention and providing protective colloid:

HEC is soluble in hot water or cold water, high temperature or boiling without precipitation, so that it has a wide range of solubility and viscosity characteristics, and non-thermal gelation;

The water retention capacity is twice as high as that of methyl cellulose, and it has better flow regulation;

It is non-ionic and can coexist with a wide range of other water-soluble polymers, surfactants, and salts. It is an excellent colloidal thickener for high-concentration electrolyte solutions;

Compared with the recognized methyl cellulose and hydroxypropyl methyl cellulose, the dispersing ability of HEC is the worst, but the protective colloid ability is the strongest.

Since the surface-treated hydroxyethyl cellulose is a powdery or fibrous solid, the following points should be followed when preparing the hydroxyethyl cellulose mother liquor:

(1) Before and after adding hydroxyethyl cellulose, it must be stirred continuously until the solution is completely transparent and clear.
(2) It must be slowly sieved into the mixing tank, and do not put a large amount or directly put hydroxyethyl cellulose into the mixing tank.
(3) Water temperature and PH value in water have a significant relationship with the dissolution of hydroxyethyl cellulose, so special attention must be paid.
(4) Do not add some alkaline substances to the mixture before the hydroxyethyl cellulose powder is soaked with water. Raising the pH after wetting helps to dissolve.
(5) As far as possible, add antifungal agent in advance.
(6) When using high-viscosity hydroxyethyl cellulose, the concentration of the mother liquor should not be higher than 2.5-3% (by weight), otherwise the mother liquor will be difficult to handle.