What is Hydroxyethyl Cellulose?

Hydroxyethyl cellulose is a non-toxic and odorless powder with excellent adhesion and film-forming properties. It has many uses. It can be used in medicine and health, combined with medicines, and can also be used in food. It can make objects more adhesive. It can also be used in building materials in daily life, as well as papermaking and other purposes. It is a relatively good alkaline substance.

preparation

1. Alkali cellulose is a natural polymer. Each fiber-based ring contains three hydroxyl groups. The most active hydroxyl group reacts to form hydroxyethyl cellulose. Soak the raw cotton linters or refined pulp in 30% liquid alkali, take it out and squeeze it after half an hour. Press until the alkaline-water ratio reaches 1:2.8 and then crush. The crushed alkaline cellulose is put into a reaction kettle, which is sealed, vacuumed, and filled with nitrogen. The vacuuming and nitrogen filling are repeated to completely replace the air in the kettle. Pre-cooled ethylene oxide liquid was pressed in, cooling water was passed into the jacket of the reactor, and the temperature was controlled at about 25°C to react for 2 hours to obtain crude hydroxyethyl cellulose. The crude product was washed with alcohol, neutralized with acetic acid to pH 4-6, and then cross-linked and aged with glyoxal. Then wash with water, centrifuge and dehydrate, dry and grind to obtain hydroxyethyl cellulose. Raw material consumption (kg/t): cotton linters or low-gluten pulp: 730-780, liquid alkali (30%): 2400, ethylene oxide: 900, alcohol (95%): 4500, acetic acid: 240, glyoxal (40%): 100-300.

2. Gas phase method: The gas phase method is to add additives or diluents during the reaction process, and the alkali fiber and EO react in the gas phase. The cotton fibers were immersed in 18.5% NaOH solution, activated, squeezed, crushed and placed in a reactor. The reactor was evacuated and filled with nitrogen twice, EO was added, and the reaction was carried out at a vacuum degree of 90.64 kPa and 27-32°C for 3-3.5 hours to obtain the product.

3. Liquid phase method: The liquid phase method is to carry out the etherification reaction in the presence of a diluent. After alkalization and pressing, the cotton linters are reacted with EO at 20-60°C for 1-3h in the presence of a diluent to obtain crude hydroxyethyl cellulose. Commonly used diluents are acetone, isopropanol, tert-butyl alcohol or mixtures thereof. The product remained insoluble in the diluent.

Both the gas phase method and the liquid phase method require the pre-preparation of alkaline cellulose, that is, the cellulose is immersed in an 18% NaOH solution at about 20°C for degreasing. After the etherification reaction, it is neutralized, washed, dried, and crushed to obtain the final product.

Application Areas

Used as adhesive, surfactant, colloid protective agent, dispersant, emulsifier and dispersion stabilizer, etc. It has a wide range of applications in coatings, inks, fibers, dyeing, papermaking, cosmetics, pesticides, mineral processing, oil production and medicine.

1. It is generally used as a thickener, protective agent, adhesive, stabilizer, and additive for the preparation of emulsions, jellies, ointments, lotions, eye cleansers, suppositories and tablets. It is also used as a hydrophilic gel, skeleton material, and for the preparation of skeleton-type sustained-release preparations. It can also be used in food as a stabilizer.

2. Used as sizing agent in textile industry, bonding, thickening, emulsifying, stabilizing and other auxiliary agents in electronics and light industry sectors.

3. Used as thickener and filtrate reducer for water-based drilling fluid and completion fluid, with obvious thickening effect in salt water drilling fluid. It can also be used as a fluid loss reducer for oil well cement. It can be cross-linked with multivalent metal ions to form a gel.

4. This product is used as a dispersant for water-based gel fracturing fluid for petroleum extraction by fracturing method, and for polymers such as polystyrene and polyvinyl chloride. It can also be used as a latex thickener in the paint industry, a hygroscopic resistor in the electronics industry, and a cement retarder and moisture retainer in the construction industry. Glazing in ceramic industry and toothpaste adhesive. It is also widely used in printing and dyeing, textiles, papermaking, medicine, hygiene, food, cigarettes, pesticides and fire extinguishing agents.

5. As surfactant, colloid protective agent, emulsion stabilizer for vinyl chloride, vinyl acetate and other emulsions, as well as thickener, dispersant and dispersion stabilizer for latex. It is widely used in coatings, fibers, dyeing, papermaking, cosmetics, medicine, pesticides, etc. It also has many uses in oil extraction and machinery industries.

6. Hydroxyethyl cellulose has surface activity, thickening, suspension, bonding, emulsification, film-forming, dispersion, water retention and protection effects in solid and liquid pharmaceutical preparations.

7. Used as dispersant for the extraction of water-based gel fracturing fluid for petroleum, polyvinyl chloride, polystyrene and other polymers. It can also be used as a latex thickener in the paint industry, a cement retarder and moisture retainer in the construction industry, a glazing agent in the ceramic industry, and a toothpaste adhesive. It is also widely used in printing and dyeing, textile, papermaking, medicine, sanitation, food, cigarettes and pesticides and other industrial fields.