Analysis of the thickening effect of hypromellose
Hydroxypropyl methyl cellulose has good viscosity to wet mortar, can significantly improve the bonding performance between the wet mortar and the base layer, and improve the anti-sagging performance of the mortar. It is widely used in mortar, external wall insulation and surface bonding mortar.
The thickening effect of cellulose ether can also increase the uniformity and anti-dispersion ability of fresh cement-based materials, and prevent the delamination, segregation and seepage of mortar and concrete. It can be used for fiber concrete, underwater concrete and self-compacting concrete.
Hydroxypropyl methylcellulose increases the viscosity of cement-based materials from the viscosity of the cellulose ether solution. The viscosity of cellulose ether solutions is usually evaluated by the “viscosity” index. The viscosity of cellulose ether usually refers to the measured value of the specified viscosity of a certain concentration of cellulose ether solution under a predetermined temperature condition using a measuring instrument.
Viscosity is an important parameter for evaluating the properties of cellulose ethers. Hydroxypropyl methyl cellulose is a kind of non-ionic cellulose mixed ether. The higher the viscosity of the hydroxypropyl methylcellulose solution, the better the viscosity of the cement-based material and the better the adhesion to the substrate.
The stronger the anti-sagging and anti-dispersion ability, but if the viscosity is too large, it will affect the fluidity and operability of cement-based materials. Therefore, the viscosity of the cellulose ether used in dry-mix mortar is usually 15,000 to 60,000 mPa. S-1, self-leveling mortar and self-compacting concrete that require relatively high fluidity require low viscosity of cellulose ether.
In addition, the thickening effect of hydroxypropyl methylcellulose increases the water consumption of cement-based materials and increases the output of mortar.