Carboxylmethyl cellulose sodium (CMC) is an anionic polymer compound synthesized from refined short cotton.Molecular weight of 6400 (soil 1000), with excellent water solubility and film formation, widely used in petroleum, daily chemical, light industry, food, medicine and other industries, known as the “industrial monosodium glutamate”.
In April 1989, the Ministry of Chemical Industry listed CMC-Na as the “eighth Five-Year plan product of fine chemical industry in new fields”. CMC.
Na production development to today, there are mainly two synthetic methods, kind is water coal direct method (alkali injection method), the other is the use of organic soluble media dissolution method, because the latter has the characteristics of less alkali, etherification time, etherification agent utilization rate, so it has been widely used.
However, at present, CMC-Na used in China generally has problems such as low qualified rate, greatly rising cost and slow development of new products.
The main measures of CMC-Na quality are substitution (DS) and viscosity, and the properties of CMC-Na from DS; as the substitution increases, the better the transparency and stability of the solution.
It is reported that the CMC-Na substitution degree is better transparent at 0. 7-1.2, and the aqueous solution viscosity of pH is maximum at 6-9. In order to ensure its quality, in addition to choosing the etherification agent, some factors affecting the substitution degree and viscosity, such as the dosage relationship between alkali and etherification agent, etherification time, system water content, temperature, pH value, solution concentration, etc.