In this article we introduce HEC in the Coating Industry.
Hydroxyethyl cellulose (HEC) is a white or light yellow, odourless, non-toxic fibrous or powdered solid. Prepared by etherification of basic cellulose and ethylene oxide (or chloroethanol), a non-ionic soluble cellulose ether.
Due to its good thickening, suspending, dispersing, emulsifying, bonding, film forming, moisture protection and protective colloid properties.HEC has been widely used in oil extraction, coatings, construction, pharmaceuticals and food, textiles, paper and polymerisation reactions.
As a non-ionic surfactant, hydroxyethyl cellulose (HEC) also has the following properties in addition to the properties mentioned above:
Hydroxyethyl cellulose (HEC) is soluble in hot or cold water. And it does not precipitate at high temperature or boiling. So it has a wide range of solubility and viscosity.
The water retention capacity of hydroxyethyl cellulose (HEC) is double that of methyl cellulose (MC). And it has better flowing adjust-ability.
Hydroxyethyl cellulose (HEC) is an excellent colloidal thickener with high-concentration electrolyte solutions. Which can coexist with a wide range of other products like water-soluble polymers, surfactants and salts, etc.
Compared with methyl cellulose (MC)and hydroxypropyl methyl cellulose (HPMC). Hydroxyethyl cellulose (HEC) has the worst dispersing power but the strongest colloid protective capability.
How to apply HEC ?
Adding HEC directly in the production process is the simplest method, which takes a shorter.
First, please add clean water into a large bucket equipped with a high-shear mixer.
Second, please stir continuously at a low speed. And slowly sift hydroxyethyl cellulose (HEC) into the solution uniformly. And continue to stir until all the particles are soaked in the solution.
Then, please add various additives such as pigments, dispersing aids, ammonia and preservative into the solution. Then stir the solution until all hydroxyethyl cellulose (HEC) is completely dissolved (the solution viscosity is significantly increased) before adding other components to the formula to react.
Hydroxyethyl cellulose (HEC) can also be used to make mother solution for preparation use.
First, please prepare a higher-concentration mother solution. And then add it to the product. This method is more flexible because it can be directly added to the finished product. But it must be stored for an appropriate time. This method does not need a high-strain stirrer but a stirrer with normal power to keep the hydroxyethyl cellulose (HEC) uniformly dispersing in the solution.
Then, please continue stirring until it is completely dissolved into a viscous solution. However, please be noted that the anti-fungal agent must be added to the mother solution as soon as possible.
When equipping the master batch of hydroxyethyl cellulose, the following points should be noted.
(1) Before and after adding the hydroxyethyl cellulose, it must be stirred continuously until the solution is completely transparent and clarified.
(2) It must be sieved slowly into the mixing drum and not in large quantities or in lumps or spheres or directly into the drum.
(3) The temperature of the water and the pH value of the water have a clear relationship with the dissolution of hydroxyethyl cellulose and special attention must be paid to this.
(4) Never add alkaline substances to the mixture before the hydroxyethyl cellulose powder has been wetted with water. Increasing the pH value after wetting will help dissolution.
(5) Whenever possible, add mould inhibitors in advance.
(6) When using a high viscosity type of hydroxyethyl cellulose, the concentration of the master batch should not be higher than 2.5-3% (by weight) otherwise the master batch is difficult to work with.
That’s about HEC in the Coating Industry introduction.