Views: 0 Author: Site Editor Publish Time: 2022-01-22 Origin: Site
HEC Hydroxyethyl cellulose is a white to pale yellow fibrous or powdery solid. Non-toxic, tasteless. It is a nonionic cellulose ether, soluble in cold and hot water due to the hydrophilic hydroxyethyl in the molecule. Its aqueous solution has a pH value of 6.5 ~ 8.5 and is stable to heat. HEC has different solubility according to the degree of substitution (DS). Insoluble in most organic solvents. It has the properties of thickening, suspension, adhesion, emulsification, dispersion and moisture retention, etc., and can prepare solutions with different viscosity ranges. It has unusually good salt solubility to the dielectric, and its aqueous solution is allowed to contain high concentration of salts and remains unchanged.
Hydroxyethyl cellulose HEC production raw materials
Main raw materials: City cellulose (cotton staple or low pulp), liquid alkali, ethylene oxide, ethylene diron (40%)
Alkali fiber system is a natural polymer, each fiber ring contains three hydroxyl groups, the most active hydroxyl reaction to form hydroxyethyl cellulose. Soak the raw cotton staple or refined meal pulp in 30% liquid alkali for half an hour and press it. Crush to 1: 2.8 cases of alkaline water, then crush. The crushed alkali cellulose is put into the reaction kettle, sealed, vacuumized, filled with nitrogen, and repeated vacuumized and filled with nitrogen to replace the air in the case. The pre-cooled ethylene oxide liquid was pressed into the reactor jacket with cooling water, and the reaction was controlled at about 25C for 2h to obtain hydroxyethyl fiber cable crude product. Crude products with alcohol to wash, add acetic acid neutralization to VLL 46, jean add glyoxal crosslinking aging. Then wash with water, centrifugal dehydration, drying, grinding, hydroxyethyl cellulose.
1.1 liquid alkali
Pure product is colorless transparent liquid. Relative density 2. 130, melting point 318.4C, boiling point 1390C. Caustic soda on the market has a cycle state. And liquid two kinds: pure solid caustic soda white, flake, block, granular and rod shape, cytoplasm: pure liquid caustic soda called liquid alkali, colorless transparent liquid. Industrial products contain impurities, mainly sodium chloride and sodium carbonate, and sometimes a small amount of iron oxide.
1.2 ethylene oxide
Ethylene oxide is an organic compound, chemical formula C2H40, is a toxic carcinogen. Epoxy cane is flammable and explosive, not easy to transport over long distances, so there is a strong regional. It is widely used in washing, pharmaceutical, printing and dyeing industries. 3 oxyethane (E0) is the simplest ring ether, belongs to heterocyclic compounds, is an important petrochemical products. Ethylene oxide is a colorless transparent liquid at low temperature and a colorless gas with pungent smell of legs at room temperature. The vapor pressure of the gas is high and can reach 141kPa at 30C. This high vapor pressure determines the strong penetration of epoxy z.alkane when steaming. Melting point (C): -112.2. Relative density (water -1) : 0.8711
Yellow ribbed or irregularly flaky, turning white on cooling.
Hydroxyethyl cellulose HEC manufacturing process
Put cotton staple or refined pulp in 30% lye. Remove and press. It is then crushed and reacted with pre-cooled ethylene oxide to produce crude hydroxyethyl cellulose. Then wash with alcohol and add acetic acid to wash and neutralize. Then add glyoxal crosslinking aging, quick washing with water. Finally, after centrifugation dehydration, drying and grinding, the finished HEC product is obtained.
A method for producing low ash HEC hydroxyethyl cellulose by continuous washing process belongs to the technical field of materials. The technical problem to be solved is to provide a continuous washing process with high production efficiency, small loss of washing solvent and material and low cost to produce low ash HEC hydroxyethyl cellulose. The method of continuous washing process to produce low ash HEC hydroxyethyl cellulose is characterized in the following steps: A, the crude hydroxyethyl cellulose and crosslinking agent mixed, crosslinking treatment to get slurry A; B. Add washing solvent to the slurry A obtained in step A to obtain slurry B; C. Add the slurry C obtained in step B into a rotary pressure centrifuge and obtain low ash hydroxyethyl cellulose after continuous washing. The method can significantly improve the working efficiency, significantly improve the loss of washing solvent and material, and significantly reduce the ash content of the product, which is worthy of popularization and application.