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.
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.
How to use hydroxyethyl cellulose? How to add it?
1. Add directly in production
This method is the simplest and takes the shortest time.
Add clean water to a large bucket equipped with a high shear mixer. Start to stir continuously at low speed and slowly sieve the hydroxyethyl cellulose into the solution evenly. Continue to stir until all particles are soaked. Then add preservatives and various additives. Such as pigments, dispersing aids, ammonia water, etc. Stir until all the hydroxyethyl cellulose is completely dissolved (the viscosity of the solution increases significantly) before adding other components in the formula for reaction.
2. Equipped with mother liquor waiting
It is to prepare the mother liquor with higher concentration first, and then add it to the product. The advantage of this method is that it has greater flexibility and can be directly added to the finished product, but it must be properly stored. The steps of this method are similar to most of the steps in method 1; the difference is that there is no need for a high-shear agitator, and only some agitators with sufficient power to keep the hydroxyethyl cellulose uniformly dispersed in the solution can be continued without stopping Stir until completely dissolved into a viscous solution. However, it must be noted that the fungicide must be added to the mother liquor as soon as possible.
Kind tips
Since the surface-treated hydroxyethyl cellulose is a powdery or fibrous solid, when preparing hydroxyethyl cellulose mother liquor, remind you to pay attention to the following points:
(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 sifted into the mixing tank, and do not pour the hydroxyethyl cellulose into the mixing tank in large quantities or directly into lumps and balls.
(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 soaking will aid in dissolution.
(5) Add antifungal agent as much as possible 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.