Hydroxyethyl cellulose (HEC)
Hydroxyethyl cellulose (HEC)
It is a white or light yellow, odorless, non-toxic fibrous or powdery solid.
Because HEC has good properties of thickening, suspending, dispersing, emulsifying, bonding, film forming, protecting moisture and providing protective colloids. Has been widely used in oil extraction, coatings, construction, pharmaceutical and food, textile, paper and polymer polymerization.
40 mesh screening rate ≥99%; softening temperature: 135-140 ° C; performance density: 0.35-0.61 g / ml; decomposition temperature: 205-210 ° C, slow burning rate; equilibrium temperature: 23 ° C, 50% Rh is 6%, and 84% is 29% rh.
It is soluble in cold water and soluble in hot water. Generally, it is insoluble in most organic solvents. The pH value changes little in the range of 2-12, but the viscosity decreases beyond this range.
Important nature
As a nonionic surfactant, hydroxyethyl cellulose has the following properties in addition to thickening, suspending, binding, bubbling, film forming, dispersing, water retention and providing protective colloid:
1. HEC is soluble in hot or cold water, and does not precipitate at high temperature or boiling, so that it has a wide range of solubility and viscosity characteristics, so non-thermogelability;
2. The non-ionic type itself can coexist with other water-soluble polymers, surfactants and salts in a wide range, so is an excellent colloid thickener containing a high concentration of electrolyte solution;
3, water retention capacity is twice as high as methyl cellulose, with good flow regulation;
4. The dispersing ability of HEC is the worst dispersing ability compared with the recognized methyl cellulose and hydroxypropyl methyl cellulose, but the protective colloid is the strongest.
Precautions
Since the surface-treated hydroxyethyl cellulose is a powdery or cellulose solid, it is easy to handle and dissolve it in dissolve water as long as the following matters are note.
1. Before and after the addition of hydroxyethylcellulose, it must be stirred continuously until the solution is completely clear and clear.
2. It must be slowly sieved into the mixing tank. Do not add the hydroxyethyl cellulose which has been formed into a block and a spherical shape directly into the mixing tank.
3. The water temperature and pH value in water have a significant relationship with the dissolution of hydroxyethyl cellulose, so special attention must be paid.
4. Never add some alkaline substances to the mixture before the hydroxyethyl cellulose powder is warm by water. Increasing the pH after warming up will help dissolve.
5, as far as possible, add anti-fungal agents early.
6. When using the high viscosity type hydroxyethyl cellulose, the concentration of the mother liquor should not be higher than 2.5-3%, otherwise the mother liquor is difficult to handle.
The post-treated hydroxyethyl cellulose generally does not easily form a block or a globular shape, and does not form water to form a poorly soluble globular colloid.