Hydroxyethyl cellulose (HEC).
Structural Formula:
Quality Standard Project Indicators.
Degree of molar substitution (m.).s） 1.8-2.0
Moisture (%): 10
Water insoluble matter ( ) 05
pH 60-8.5
Heavy metals (ugg) 20
Ash ( ) 5
Viscosity (mpa.)s)2 20 aqueous solution 5-60000
Lead ( ) 0001
Hydroxyethyl cellulose (HEC) is a white or light yellow, odorless, non-toxic fibrous or powdered solid, prepared by etherification reaction of alkaline cellulose and ethylene oxide (or chloroethanol), which belongs to the non-ionic soluble cellulose ethers. Due to its good thickening, suspension, dispersion, emulsification, bonding, film formation, moisture protection and protective colloidal properties, HEC has been widely used in oil extraction, coatings, construction, medicine and food, textile, papermaking and polymer polymerization reactions. 40 mesh screening rate 99%;Softening temperature: 135-140;Performance density: 035-0.61g/ml;Decomposition temperature: 205-210;Burns slower;Equilibrium temperature content: 23;6% at 50% RH and 29% at 84% RH.
It is soluble in cold water and hot water, and generally insoluble in most organic solvents. The pH value changes little in viscosity in the range of 2-12, but decreases beyond this range.
As a non-ionic surfactant, hydroxyethyl cellulose has the following properties in addition to thickening, suspension, bonding, floating, film-forming, dispersing, water retention and providing protective colloidal effects
1. HEC can be 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, as well as non-thermal gelatinity
2. The non-ionic type can coexist with other water-soluble polymers, surfactants and salts in a wide range, and is an excellent colloidal thickener containing high concentration electrolyte solution
3. The water holding capacity is twice as high as that of methyl cellulose, and it has better flow regulation, 4. The dispersion capacity of HEC is the worst compared with the recognized methyl cellulose and hydroxypropyl methyl cellulose, but the colloidal protection ability is the strongest.
1 Added directly at the time of production.
1 Add clean water to a large vat with a high-cut agitator.
2. Start stirring at low speed and slowly sieve the hydroxyethyl cellulose into the solution.
3 Continue stirring until all particles are soaked through.
4. Then add lightning protection agents, alkaline additives, etc. such as pigments, dispersion additives, and ammonia.
5. Stir until all hydroxyethyl cellulose is completely dissolved (the viscosity of the solution increases significantly) before adding other components in the formula and grinding until the finished product is finished.
2. Equipped with mother liquor for use.
This method is to first prepare a mother liquor with a higher concentration, and then add it to the latex paint. The advantage of this method is that it is more flexible and can be directly added to the finished lacquer, but it should be stored appropriately. The procedure is similar to Part 4 of Method 1, except that it does not need to be mixed until it completely dissolves into a viscous solution.
3. Prepare for porridge phenology.
Since organic solvents are undesirable solvents for hydroxyethylcellulose, these organic solvents can be used to prepare the porridge. The most commonly used organic solvents are organic liquids such as ethylene glycol, propylene glycol and film formers such as ethylene glycol or diethylene glycol butyl acetate in lacquer formulations. Ice water is also a bad solvent, so it is often used together with organic liquids to prepare porridge. The hydroxyethyl cellulose of the porridge can be directly added to the lacquer, and the hydroxyethyl cellulose has been soaked in the porridge. When added to the lacquer, it dissolves immediately and has a thickening effect. After addition, it is still necessary to stir continuously until the hydroxyethyl cellulose is completely dissolved and homogeneous. Generally, the porridge is made by mixing six parts of organic solvent or ice water with one part of hydroxyethyl cellulose, and after about 6-30 minutes, the hydroxyethyl cellulose will hydrolyze and swell significantly. In summer, the water temperature is too high, so it is not suitable to use porridge.
Since surface-treated hydroxyethyl cellulose is a powder or cellulose solid, it is easy to handle and dissolve in water as long as the following precautions are taken.
1 Before and after adding hydroxyethylcellulose, stirring must be kept until the solution is completely transparent and clear.
2 It must be sifted into the mixing drum slowly, and do not add a large number of hydroxyethyl cellulose that has been formed into lumps and balls directly into the mixing drum.
3 Water temperature and pH value in water have a significant relationship with the dissolution of hydroxyethyl cellulose, so special attention should be paid to it.
4 Do not add some alkaline substances to the mixture before the hydroxyethylcellulose powder is warmed in water. Raising the pH level after warming will help with dissolution.
5 As far as possible, add antifungal agents as early as possible.
6 When using high-viscosity hydroxyethyl cellulose, the concentration of the mother liquor should not be higher than 25-3%, otherwise the mother liquor is difficult to operate. Post-treated hydroxyethyl cellulose is generally not easy to form lumps or globules, nor does it form insoluble globular colloids when added to water.
7. Uses: Generally used as thickeners, protective agents, adhesives, stabilizers and additives for the preparation of emulsions, gels, ointments, lotions, eye clearers, suppositories and tablets, and also used as hydrophilic gels, skeleton materials, preparation of skeleton-type sustained-release preparations, and can also be used as stabilizers in food.