Preparation Method Of Carboxymethyl Hydroxypropyl Cellulose

This paper explains the maufacturing technology of carboxymethyl hydroxypropyl cellulose taking natural cotton linters as main raw material using alkalization and etherification.There are three methods to prepare carboxymethyl hydroxypropyl, which are carboxymethylation followed by hydroxypropylation, hydroxypropylation followed by carboxymethylation and hydroxypropylation simultanuously with carboxymethylation. The two formers have such disadvantages as long production cycle, high consumption of solvents and energy and low viscosity for product because its etherification is conducted stepwisely and also the intermediates have to be purified.The paper supposes that carboxymethyl hydroxypropyl cellulose composite ether can be produced by single-step etherification instead of two-step etherification process. The method has uniform reaction so that the product has high vicosity, good acid and salt resistances. Carboxymethyl hydroxypropyl cellulose product containing different amount of carboxymethyl and hydroxypropyl is made by adjusting relative amount of epoxy propane and chloroethanoic acid.The test results show carboxymethyl hydroxypropyl cellulose using single-step method has short production cycle, low solvent consumption and good salt and acid resistances. The product is applicable in many industries as coating,toothpaste, food & drinks and petrol drilling etc. Comparing with other cellulose ethers, it is poiwerfully competitive.