Today, we will talk to you about the common use of hydroxyethyl cellulose in paint and coatings. Paint, traditionally called coatings in China. The so-called coating is coated on the surface of the object to be protected or decorated, and can form a continuous film that is firmly attached to the object to be coated.
What is hydroxyethyl cellulose?
Hydroxyethyl cellulose (HEC), a white or light yellow, odorless, non-toxic fibrous or powdery solid, prepared by etherification of alkaline cellulose and ethylene oxide (or chlorohydrin), belonging to the genus Nonionic soluble cellulose ethers. Because HEC has good properties of thickening, suspending, dispersing, emulsifying, bonding, film-forming, protecting moisture and providing protective colloids, it has been widely used in oil exploration, coatings, construction, medicine and food, textiles, papermaking and polymers. 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, flotation, film-forming, dispersing, water retention and providing protective colloids:
HEC is soluble in hot or cold water, and does not precipitate at high temperature or boiling, making it have a wide range of solubility and viscosity characteristics, as well as non-thermal gelling;
The water retention capacity is twice that of methyl cellulose, and it has better flow regulation;
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;
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.
How to use hydroxyethyl cellulose? How to add it?
Add directly at the time of production – this method is the easiest and takes less time.
Add clean water to the vat equipped with a high-shear blender. Begin stirring continuously at low speed and slowly sift the hydroxyethyl cellulose evenly into the solution. Continue stirring until all particles are soaked through. 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 to carry out the reaction.
Equipped with mother liquor.
It is to prepare a mother liquor with a 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 used, and continue to Stir until completely dissolved into a viscous solution. However, it must be noted that the antifungal agent must be added to the mother liquor as soon as possible.
Since the surface-treated hydroxyethyl cellulose is a powder or fibrous solid, Shandong Heda reminds you to pay attention to the following points when preparing the hydroxyethyl cellulose mother liquor:
(1) Before and after adding hydroxyethyl cellulose, it must be kept stirring until the solution is completely transparent and clear.
(2) It must be slowly sieved into the mixing barrel, and do not directly connect the hydroxyethyl cellulose and hydroxyethyl cellulose into the mixing barrel in large quantities or in the form of lumps and balls.
(3) The water temperature and the pH value of the water have an obvious relationship to the dissolution of hydroxyethyl cellulose, so special attention should be paid to it.
(4) Never add some alkaline substances to the mixture before the hydroxyethyl cellulose powder is soaked with water. Raising the pH only after wetting will aid in dissolution.
(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 is difficult to handle.
Post time: Nov-03-2022