Wet-mixed mortar is cement, fine aggregate, admixture, water and various components determined according to performance. According to a certain proportion, after being measured and mixed in the mixing station, it is transported to the place of use by a mixer truck, and put into a special The wet mix is stored in the container and used within the specified time.
Hydroxypropyl methylcellulose is used as a water-retaining agent and retarder of cement mortar to make the mortar pumpable. Used as a binder in plastering plaster, it improves spreadability and prolongs the working time. The water retention performance of hydroxypropyl methylcellulose HPMC prevents the slurry from cracking due to drying too fast after application, and enhances the strength after hardening. Water retention is an important performance of hydroxypropyl methylcellulose HPMC, and it is also a performance that many domestic wet-mix mortar manufacturers pay attention to. Factors affecting the water retention effect of wet-mixed mortar include the amount of HPMC added, the viscosity of HPMC, the fineness of particles, and the temperature of the use environment.
The important role of hydroxypropyl methylcellulose HPMC in wet-mix mortar mainly has three aspects, one is excellent water retention capacity, the other is the influence on the consistency and thixotropy of wet-mix mortar, and the third is the interaction with cement. The water retention effect of cellulose ether depends on the water absorption of the base layer, the composition of the mortar, the thickness of the mortar layer, the water demand of the mortar, and the setting time of the setting material. The higher the transparency of hydroxypropyl methylcellulose, the better the water retention.
Factors affecting the water retention of wet-mix mortar include cellulose ether viscosity, addition amount, particle fineness and use temperature. The greater the viscosity of cellulose ether, the better the water retention performance. Viscosity is an important parameter of HPMC performance. For the same product, the viscosity results measured by different methods are very different, and some even have doubled differences. Therefore, when comparing viscosity, it must be carried out between the same test methods, including temperature, rotor, etc.
Generally speaking, the higher the viscosity, the better the water retention effect. However, the higher the viscosity and the higher the molecular weight of HPMC, the corresponding decrease in its solubility will have a negative impact on the strength and construction performance of the mortar. The higher the viscosity, the more obvious the thickening effect on the mortar, but it is not directly proportional. The higher the viscosity, the more viscous the wet mortar will be, that is, during construction, it is manifested as sticking to the scraper and high adhesion to the substrate. But it is not helpful to increase the structural strength of the wet mortar itself. During construction, the anti-sag performance is not obvious. On the contrary, some modified hydroxypropyl methylcellulose with medium and low viscosity has excellent performance in improving the structural strength of wet mortar.
The greater the amount of cellulose ether HPMC added in the wet-mixed mortar, the better the water retention performance, and the higher the viscosity, the better the water retention performance. Fineness is also an important performance index of hydroxypropyl methylcellulose.
The fineness of hydroxypropyl methylcellulose also has a certain impact on its water retention. Generally speaking, for hydroxypropyl methylcellulose with the same viscosity but different fineness, the finer the finer the finer the The water retention effect is better.
In wet-mixed mortar, the addition amount of cellulose ether HPMC is very low, but it can significantly improve the construction performance of wet-mixed mortar, and it is a main additive that affects the construction performance of mortar. Reasonable selection of the correct hydroxypropyl methylcellulose has a great influence on the improvement of the performance of wet-mixed mortar.
Post time: Mar-31-2023