1. The quality of hydroxypropyl methylcellulose produced in horizontal and vertical kettles
Hydroxypropyl methyl cellulose is a cellulose ether derivative, and its production currently has two process routes: the horizontal kettle dry method and the vertical kettle solvent method;
1. The horizontal kettle dry production process is a production process developed in the early stage. The main production process is that the cotton fiber is kneaded and alkalized in a liquid alkali, and then an etherification agent is introduced for etherification reaction. This dry production process is not conducive to the diffusion and penetration of the etherification agent, so the etherification reaction time is short, the efficiency is low, the cost is relatively low, the reaction is unstable, the uniformity is poor, the side reactions are many, and the quality of the obtained product is relatively poor.
2. The production process of the vertical kettle solvent method is to carry out the alkalization and etherification of cotton fibers in an inert organic solution, thus increasing the diffusion and penetration rate of the reagent, which is beneficial to the mass and heat transfer of the reaction process, and makes the reaction stable. The etherification is uniform, the consumption of the etherification agent is low, the etherification efficiency is high, the cost is relatively high, and the quality of the obtained product is high and stable. At present, the advanced production process of the solvent method is mostly adopted at home and abroad, and different companies use different solvents, and the reaction mechanism is basically the same.
2. Now due to the improvement of the production process of the horizontal kettle dry method, the output is large and the cost is slightly lower. As a new traditional craft. Also recognized by new cellulose companies