Ethyl cellulose (Ethyl cellulose ether), also known as cellulose ether, referred to as EC.
Molecular composition and structural formula: [C6H7O2(OC2H5)3] n.
1.Using
This product has the functions of bonding, filling, film forming, etc. It is used for resin synthetic plastics, coatings, rubber substitutes, inks, insulating materials, and also used as adhesives, textile finishing agents, etc., and can be used as animal in agriculture and animal husbandry Feed additive, used as adhesive in electronic products and military propellants.
2. Technical requirements
According to different uses, commercialized EC can be divided into two categories: industrial grade and pharmaceutical grade, and are generally soluble in organic solvents. For pharmaceutical grade EC, its quality standard should meet the standards of Chinese Pharmacopoeia 2000 edition (or USP XXIV/NF19 edition and Japanese Pharmacopoeia JP standard).
3. Physical and chemical properties
1. Appearance: EC is white or light gray fluid powder, odorless.
2. Properties: commercialized EC is generally insoluble in water, but soluble in different organic solvents. It has good thermal stability, extremely low ash content when burned, and rarely sticks or feels astringent. It can form a tough film. It can still maintain flexibility. This product is non-toxic, has strong anti-biological properties, and is metabolically inert, but it is prone to oxidative degradation under sunlight or ultraviolet light. For special-purpose EC, there are also types that dissolve in lye and pure water. For EC with a degree of substitution above 1.5, it is thermoplastic, with a softening point of 135~155°C, a melting point of 165~185°C, a pseudo specific gravity of 0.3~0.4 g/cm3, and a relative density of 1.07~1.18 g/cm3. The degree of etherification of EC affects solubility, water absorption, mechanical properties and thermal properties. As the degree of etherification increases, the solubility in lye decreases, while the solubility in organic solvents increases. Soluble in many organic solvents. Commonly used solvent is toluene/ethanol as 4/1 (weight) mixed solvent. The degree of etherification increases, the softening point and hygroscopicity decrease, and the use temperature is -60°C~85°C. Tensile strength 13.7~54.9Mpa, volume resistivity 10*e12~10*e14 ω.cm
Ethyl cellulose (DS: 2.3-2.6) is a non-ionic cellulose ether that is insoluble in water but soluble in organic solvents.
1.Not easy to burn.
2.Good thermal stability and excellent thermos-plasticity.
3.Does not change color to sunlight.
4.Good flexibility.
5.Good dielectric properties.
6.It has excellent alkali resistance and weak acid resistance.
7.Good anti-aging performance.
8.Good salt resistance, cold resistance and moisture absorption resistance.
9.It is stable to chemicals and will not deteriorate in long-term storage.
10.It can be compatible with many resins and has good compatibility with all plasticizers.
11.It is easy to change color under strong alkaline environment and heat.
4. Dissolution method
The most commonly used mixed solvents for ethyl cellulose (DS: 2.3~2.6) are aromatic hydrocarbons and alcohols. Aromatics can be benzene, toluene, ethylbenzene, xylene, etc., with a amount of 60-80%; alcohols can be methanol, ethanol, etc., with an amount of 20-40%. Slowly add EC to the container containing the solvent under stirring until it is completely wetted and dissolved.
CAS No.： 9004-57-3
5. Application
Because of its water insolubility, ethyl cellulose is mainly used as a tablet binder and film coating material, etc., and can also be used as a matrix material blocker to prepare various types of matrix sustained-release tablets;
Used as a mixed material to prepare coated sustained-release preparations and sustained-release pellets;
It is used as an encapsulation auxiliary material to prepare sustained-release microcapsules, so that the drug effect can be released continuously and prevent some water-soluble drugs from taking effect prematurely;
It can also be used as a dispersant, stabilizer, and water-retaining agent in various pharmaceutical dosage forms to prevent moisture and deterioration of medicines and improve the safe storage of tablets.