With the development of China’s national economy, the fast dissolving HPMC is widely used, and the annual demand is increasing. It can be used as an emulsifier, thickener, dispersant, stabilizer, sizing agent, film forming agent, water retaining agent, etc., in petroleum, textile, daily chemical, cigarette, paper, construction, food, medicine and other industrial fields.
The traditional HPMC ether production process is: alkalized cellulose refined cotton with sodium hydroxide under certain conditions to form cellulose sodium, and then etherified with propylene oxide and methyl chloride. The reaction is carried out to form HPMC ether, which is neutralized, recovered, washed, and dried to obtain a dry finished product. The shortcoming of this kind of process is that the production of HPMC ether is poor desperation in the practical application, and it is easy to coagulation, the dissolution is slow, which limited the application field. For example, in the pasty plaster of building materials, the cluster is difficult to dissolve in the water and cannot be used normally. Therefore, in practical applications, it is necessary to dissolve in advance, which increases the construction difficulty and construction time.
The purpose of this process is to solve the technical problem that the existing HPMC ether is not easy to dissolve, easy to coagulation and the dispersion effect is poor, and a production process of fast dissolving HPMC ether is provided.
The reaction principle is: converting the carbonyl compound of the cellulose ether into an acetal by using an aldehyde group (-CH0) of glyoxal and after completion of the reaction, fast-dissolving HPMC ether having the same structural formula as the prior art is obtained. .
The fast dissolving HPMC ether prepared by the process introduces an aldehyde group in the preparation process. The aldehyde and the ketone all contain a carbonyl group, and the carbonyl group is a relatively active group, especially the aldehyde is extremely sensitive to alkali, easy to be oxidized, but the acetal is equivalent to cytidine diphosphate ether ,therefore, it is relatively stable. The acetal can be hydrolyzed to the original carbonyl compound, that is, when the carbonyl group in the molecule coexists with other functional groups, only other functional groups are expected to react, and the carbonyl group is not affected, then the carbonyl compound can be converted into an acetal, after the reaction is completed, hydrolyze it. Under the premise that other indicators meet the requirements, the production does not coagulation when dissolving, disperses and dissolves quickly, which solves the restriction in practical application, and expands the application field, such as application in paste putty and construction glue. The dispersion can reach 100%.
It can be seen from the above that the main physical and chemical indicators of the fast dissolving HPMC ether prepared by this process meet the requirements, while satisfy the market demand.
In order to further prove the advantages of this process, the fast dissolving HPMC ether prepared by this process was compared with the HPMC ether prepared by the traditional process under the same conditions; Proved that the fast dissolving HPMC of the process is immediately dispersed in cold water and can be dissolved and thickened in one hour for application. However, the conventional HPMC ether is in cold water, which is difficult to disperse. It takes 3-5 hours constantly stirred to dissolve and thicken, then put into application. Compared with that, the fast dissolving HPMC can improve the work efficiency significantly based on actual dissolution time.
Post time: Mar-20-2019