hydroxypropyl methylcellulose HPMC in Plastering MortarFebruary 2nd 2023
HPMC manufacturer-the impact of tile adhesive opening time
When the rubber powder and the cellulose ether coexist in the wet mortar. Some data models show rubber powder. Has a stronger kinetic energy attached to the cement hydration product.Lignite is more present in the tissue fluid, which more affects the viscosity and setting time of the mortar.
The surface tension of the cellulose ether is greater than the surface tension of the rubber powder. More cellulose ether is enrich at the mortar interface.It will be advantageous to form a hydrogen bond between the matrix and the cellulose ether.
In the wet mortar, the water in the mortar evaporates and the cellulose ether concentrates on the surface. A film is formed on the surface of the mortar within 5 minutes, which reduces the subsequent evaporation rate.
As more and more water migrates from the thicker portion of the mortar to the thinner portion of the mortar layer.The film opening portion of the initial stage is partially dissolve. And the migration of water results in more cellulose ether, which is concentrate on the surface of the mortar.Therefore, the formation of cellulose ether on the surface of the mortar has a great influence on the performance of the mortar.
1) The form film is too thin and will dissolve twice. Unable to limit water evaporation and reduce strength.
2) The form film is too thick, and the concentration of the cellulose ether in the mortar tissue liquid is high and the viscosity is large.
When the tile passes, it is not easy to break the film on the surface. From this, it is understood that the film form ability of the cellulose ether greatly affects the opening time.
The type of cellulose ether (HPMC, HEMC, MC, etc.) and the degree of etherification (degree of substitution) directly affect the film form ability of the cellulose ether. And the hardness and toughness of the film.