Views: 1 Author: Site Editor Publish Time: 2022-06-10 Origin: Site
Cellulose ether with the used etherifying agent is not the same as methyl cellulose, carboxymethyl cellulose, ethyl cellulose, benzyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, cyanoethyl cellulose, benzyl cyanoethyl cellulose, carboxymethyl hydroxyethyl cellulose and phenyl cellulose. Methyl cellulose and ethyl cellulose are more suitable.
After etherification of cellulose melting function attack obvious change, can dissolve in water, dilute acid, dilute alkali or organic solvent, melting degree of secondary originated from three elements: (1) the characteristics of the groups introduced in the process of etherification, introducing the larger the group, the lower the degree of melting, the introduction of group stronger polarity, cellulose ether more soluble in water; (2) Degree of substitution and dispersion of etherified groups in large members. A large number of cellulose ether can only be certain degree of substitution environment, only to dissolve in water, substitution degree is between 0 -- 3; (3) the aggregation degree of cellulose ether, the higher the aggregation degree, the less easy to dissolve; The lower the convergence degree, the wider the category of substitution degree soluble in water. Cellulose ether category single, high quality function, widely used in construction, lime, alcohol, drugs, dyeing, detergent, paint, medicine, paper and electronic components and other light industry.
Cellulose hydroxyl ether has specificity for hydroxyethyl cellulose and hydroxypropyl cellulose. Etherifying agents are epoxides, such as methane epoxide and propylene epoxide. Use acid or base as xanthan gum catalyst. Light industrial consumption is the reaction of alkali cellulose with etherifying agent:
Hydroxyethyl cellulose with high substitution value is soluble in both cold and hot water. Hydroxypropyl cellulose with high substitution value is soluble in cold water but not in hot water. Hydroxyethyl cellulose can be used as thickener for latex coating, dyeing printing paste, paper making glue, adhesive and screen colloid, etc. Hydroxypropyl cellulose is similar in use to hydroxyethyl cellulose. Hydroxypropyl cellulose with low substitution value can be used as a pharmaceutical excipient and can be used for both adhesion and disintegration.
Hydroxypropyl methyl cellulose
Introduction of use:
1. Construction industry: as a water retention agent and retarder of lime sand slurry, the slurry is being pumped. Mortar, plaster of Paris, putty powder or other building materials are being applied as adhesives to improve the drawing and extension of the operation time. Used for pasting ceramic tile, marble, plastic whitewash, paste strengthening agent, but also can reduce lime dosage. HPMC water retention function so that the slurry is pulled after no drying too fast and cracking, strengthen the strength after softening.
2. Ceramic building industry: widely used as adhesive in ceramic goods building.
3. Coating industry: the coating industry as a thickener, dispersant and stabilizer, is in water or inorganic solvents are stored in a good phase solubility. As a paint remover.
4 ink printing: ink industry as thickener, dispersant and stabilizer, is in water or inorganic solvents are good solubility.
5. Plastic: mold release agent, hardening agent, smoothing agent, etc.
6. PVC: PVC consumption as evacuation agent, suspension set preparation of PVC secondary additives.
7. Other: This product is also widely used in fur, paper industry, fruit and vegetable insulation and dyeing industry and other hydroxyethyl cellulose (HEC)
The name of hydroxyethyl cellulose, as a kind of nonionic surfactant, in addition to the deposit is thickening, suspension, glue, floating, into a film, evacuation, need covering colloid, water retention and also save nature is the following 1, HEC soluble in hot water or cold water, cold or boil without accumulation, to make it melt and viscosity characteristics of the deposit is large category, 2. Its non-ionic type can coexist with other water-soluble aggregates in a large category, nominal active agent and salt. It is a kind of high-quality colloidal thickener containing profound shallow dielectric filtrate. 4, HEC evacuation power compared with the recognized methyl cellulose and hydroxypropyl methyl cellulose evacuation power is the worst, but the shielding colloid power is the strongest.
Use: normally used as thickening agent, screen agent, adhesive, stabilizer and the preparation of emulsion, gel, extract, lotion, eye cleaning agent, medicine and tablet additive, also used as hydrophilic gel, bone data, preparation of bone type sustained release pharmaceutical, can also be used in the drug range as stabilizer, etc.
Hydroxyethyl cellulose (HEC) is a red or light yellow, interesting, non-toxic, fibrous or powdered liquid prepared by etherification reaction of acidic cellulose with methane epoxide (or alcohol chloride). It is a nonionic soluble cellulose ether. Because HEC is excellent thickening, suspension, evacuation, emulsification, bonding, film forming, cover moisture and need to cover colloid and other characteristics, has been widely used in alcohol mining, paint, construction, pharmaceutical products, dyeing, papermaking and high member set response and other related spheres. Screening rate of 40 mesh ≥99%; Hardening measurement: 135-140℃; Manifest density: 0.35-0.61g/ mL; Synthetic measurement: 205-210℃; The extinguishing progress is slow; Unbalanced temperature content: 23℃; 6% at 50% RH and 29% at 84% RH.